Monograph 24

Lower Back Trauma
(Lumbar Spine and Pelvis)

By R. C. Schafer, DC, PhD, FICC
Manuscript Prepublication Copyright 1997

Copied by Chiro.Org with permission from   ACAPress

Background Initial Assessment     Neurologic Levels     Tenderness Lumbar Subluxation Syndromes   Nerve Root Insults Spinal Cord Injuries   Pathologic Traction   Cord Concussion   Cord Contusions   Common Tests Developmental Defects Screening Fractures By Roentgenography   Avulsions   Fractures Arthrokinematics Functional Anatomy of the Lumbar Spine   The Lumbar Facets   The Lumbar Intervertebral Foramina   The Lumbar Nociceptive Receptor System   Importance of the Spinal Extensors Points of Greatest Spinal Stress   Motion at the Thoracolumbar Transitional Area   Motion of the Transitional Lumbosacral Area Kinesiology of the Lumbar Spine   Testing Muscle Weakness   Testing Muscle Shortening Kinematics of the Lumbar Spine Distortion Patterns   Lumbosacropelvic Rhythm   The Revealing Adams Position     Gross Observation     Segmental Faults     Standing Forward Flexion     Supine Hyperflexion Extension     Standing Hyperextension     Impeded Extension     Standing Extension from Flexion     Recumbent Hyperextension   Standing or Sitting Lateral Flexion   Rotation     Axis of Rotation     Rotation During Flexion   Loading Functional Anatomy of the Bony Pelvis   The Iliac Facets   The Sacrum   The Ischia and Pubic Bones The Sacroiliac Joints   Major Ligaments   Major Muscles     Innervation     Active Sacroiliac Motion?   Innervation and Referred Pain   Sacroiliac Dysfunction     Load Carriage Effects The Sacrococcygeal Joint The Symphysis Pubis Applied Pelvic Kinematics   Coupling Dynamics   Effects of Inhibited Coupling   Pelvic Tilt and Horizontal Rotation     Common Determinants of the Lumbar Curve   Sacroiliac Mobility     Multidirectional Mobility     Sacral Changes from Recumbent to Standing Positions     General Sacroiliac Motion During Pelvic Tipping.     Standing A-P Sacroiliac Motion     Sitting Sacroiliac Rotational Motion     Sacroiliac Motion During Lateral Flexion     Sacroiliac Motion During Gait     Sacral Motion During Respiration     Pelvic Changes During Sitting and Standing Clinical Management Electives for Low Back Strain/Sprain Commentary   Mechanical and Chemical Factors of Traumatic Low Back Pain     Characteristics of Mechanical Pain   Considerations in Adjustive Therapy   Characteristics of Chemical Pain Contusions   Low-Back Contusions   Gluteal Contusions

Management of Low-Back Spasm   General Approach   Passive Stretch   Vapocoolant Technique   Adjuncts Acute Lumbosacral Sprain/Strains   Sprains     Diagnosis     Effects     Lumbosacral Sprain     Segmental Kyphosis   Strains Biomechanical Instability   Segmental Stability   Instability Characteristics   The Role of Axial Ligaments in Static Balance     Primary Straps     The Pelvic Angle Sciatica   Clinical Signs   Classic Orthopedic/Neurologic Tests   Management Thoracolumbar Trigger Points   The Thoracic Area   The Lumbar Area   Management Intervertebral Disc Syndrome   Classes   Profile   Roentgenography Acute Lumbosacral Angle Facet Pain Syndrome   Roentgenography     Fergurson's Angle     Hadley's S Curve   Differentiation Spondylolisthesis   Profile   Roentgenography     Meyerling's Guide     Meschan's Method     The Terrier's Collar Sign Associated Signs Lumbar Spondylolysis and Spondylosis   Profile   Misdirected Terminology   Roentgenography   Management   Prognosis Reverse Spondylolisthesis Spinal Stenosis Anterior and Posterior Pelvic Tilt   Profile   Management Lateral Pelvic Inclination   Profile   Management Pelvic Muscle Considerations   Pelvic Spasm   Piriformis Spasm   Piriformis Myofascitis   Iliopsoas Spasm Trigger Points Sacroiliac Sprain   Etiology Sacroiliac Subluxation   Clinical Features Gluteal and Similar Strains Adductor Strains Pubic Sprain and Subluxation Coccyx Sprain and Subluxation The Use of Lifts in Managing Lumbosacral Distortions   The 1-2-4 Ratio   Common Types of Lifts Sacroiliac Infection Pelvic Bursitis Entrapment Syndromes of the Pelvis   Sciatic Nerve Compression   Obturator Nerve Compression   Femoral Cutaneous Nerve Compression Lumbopelvic Postural Alignment   Muscle Conditioning   Postural Realignment References and Bibliography

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Although it may be easier to teach anatomy by dividing the body into arbitrary parts, a misinterpretation can be created. For instance, we find clinically that the lumbar spine, sacrum, ilia, pubic bones, and hips work as a functional unit. Any disorder of one part immediately affects the function of the other parts. We should also keep in mind that an axial kinematic chain of weight-supporting segments extends from the occipital base to the soles of the feet.

Because the number of professional papers concerning the cause and diagnosis of low-back pain is voluminous, emphasis herein is placed on points that the author believes are important but not often emphasized in popular literature.


BACKGROUND

A wide assortment of muscle, tendon, ligament, bone, nerve, and vascular injuries in this area is witnessed during posttrauma care. As with other areas of the body, the first step in the posttrauma examination process is knowing the mechanism of injury if possible. Evaluation can be rapid and accurate with this knowledge.

Low-back disability rapidly demotivates productivity and athletic participation. The mechanism of injury is usually intrinsic rather than extrinsic. The cause can often be through overbending, a heavy steady lift, or a sudden release --all which primarily involve the muscles. IVD disorders are more often, but not exclusively, attributed to extrinsic blows and intrinsic wrenches. An accurate and complete history is invariably necessary to offer the best management and counsel.

Initial Assessment

A player injured on the field or a worker injured in the shop should never be moved until emergency assessment is completed. Once severe injury has been eliminated, transfer to a backboard can be made and further evaluation conducted at an aid station.

    Neurologic Levels

Neurologic assessment should be made as soon as logical. Muscle tonus (flaccidity, rigidity, spasticity) by passive movements is determined. Voluntary power of each suspected group of muscles against resistance is tested, and the force is compared bilaterally. Check pupil size, ability to follow finger motion, and reaction to light. Cremasteric (L1--L2), patellar (L2--L4), gluteal (L4--S1), suprapatellar, Achilles (L5--S2), plantar (S1--S2), and anal (S5--Cx1) reflexes are evaluated. Patellar and ankle clonuses are noted. Coordination and sensation by gait, heel-to-knee and foot-to-buttock tests, and Romberg's station test are checked. These are typical minimal evaluations.

  Tenderness

Tenderness is frequently found at the apices of spinal curves and not infrequently where one curve merges with another. Tenderness about spinous or transverse processes is usually of low intensity and suggests articular stress. Tenderness noted at the points of nerve exit from the spine and continuing in the pathway of the peripheral division of the nerves is a valuable aid in spinal analysis pointing to a foraminal lesion. However, the lack of tenderness is not a clear indication of lack of spinal dysfunction. Tenderness is a subjective symptom influenced by many individual structural, functional, and psychologic factors that can make it an unreliable sign. An area for clues sometimes overlooked is the presence and symmetry of lower-extremity pulses.

Keep in mind that lumbopelvic tenderness as well as pain can be referred from pelvic and lower abdominal viscera.

LUMBAR SUBLUXATION SYNDROMES

Functional revolts associated with subluxation syndromes can manifest as abnormalities in sensory interpretations and/or motor activities. These disturbances may be through one of two primary mechanisms: direct nerve disorders or be of a reflex nature.

Nerve Root Insults

When direct nerve root involvement occurs on the posterior root of a specific neuromere, it expresses as an increase or decrease in sensory awareness over the dermatome; ie, the superficial skin area supplied by the segment. Typical examples include foraminal occlusion or irritating factors exhibited clinically as hyperesthesia, particularly on the (1) anterolateral aspects of the leg, medial foot, and great toe, when involvement occurs between L4 and L5 and (2) posterolateral aspect of the lower leg and lateral foot and toes when involvement occurs between L5 and S1. In other instances, nerve root involvement may cause hypertonicity and the sensation of deep pain in the muscles supplied by the neuromere. For example, L4 and L5 involvement, with deep pain or cramping sensations in the buttock, posterior thigh and calf, or anterior tibial muscles. In addition, direct pressure over the nerve root or its distribution may be particularly painful.

Reflexes. Nerve root insults from subluxations may also be evident as disturbances in motor reflexes and/or muscle strength. Examples of these reflexes include the deep tendon reflexes such as seen in reduced patella and Achilles tendon reflexes when involvement occurs between L4 and L5. These reflexes should be compared bilaterally to judge whether any hyporeflexia is unilateral. Unilateral hyperreflexia commonly indicates an upper motor neuron lesion.

Atrophy. Prolonged and/or severe nerve root irritation often causes trophic changes in the tissues supplied. This is characterized by obvious atrophy that would be unusual in athletes and physical laborers. Such a sign is particularly objective when the circumference of an involved limb is measured at the greatest girth in the initial stage and this value is compared to measurements taken in later stages.

Kemp's Test. While in a sitting position, the patient is supported by the examiner who reaches around the patient's shoulders and upper chest from behind. The patient is directed to lean forward to one side and then around to eventually bend obliquely backward by placing his palm on his buttock and sliding it down the back of his thigh and leg as far as possible. The maneuver is similar to that used in cervical compression. If this compression maneuver causes or aggravates a pattern of radicular pain in the thigh and leg, it suggests nerve root compression. It may also indicate a strain or sprain and thus be present when the patient leans obliquely forward or may arise at any point in motion.

Senior Citizens. Since the elderly weekend athlete is less prone to an actual herniation of a disc due to lessened elasticity involved in the aging process, other reasons for nerve root compression are usually the cause. Degenerative joint disease, exostoses, inflammatory or fibrotic residues, narrowing from disc degeneration or cord stenosis, tumors --all must be evaluated.

SPINAL CORD INJURIES

Any shade of sensory abnormality, objective or subjective, should immediately raise suspicion of possible injury to the spinal cord or cauda equina. White/Panjabi report studies showing that, with severe spinal trauma, relaxed muscles appear to be associated with less cord injury than when the muscles are strongly tensed.

Injuries to the lumbar cord or its tail occur from vertebral fractures, dislocations, or penetrating wounds in severe accidents. In rare instances, the cord may be damaged from violent falls. The T12--L1 and L5--S1 areas are the common sites of injury, especially those of crushing fractures with cord compression. Neurologic symptoms develop rapidly. The higher the injury, the more fibers will be involved. More common than these occurrences are cord tractions, concussions, and less frequent contusions.

Pathologic Traction

A scoliotic lumbar deviation must always be attended by a commensurate vertebral body rotation to the convex side. If this does not occur, it is atypical and likely pain producing. If the vertebral bodies were not subject to the law of rotation during bending, the spine would have to lengthen during bending, and its contents (ie, cord, cauda equina, and their coverings) would be subjected to considerable stretching. Thus, in a case of scoliotic deviation in the lumbar area without body rotation toward the convex side, signs indicating undue tension within the vertebral canal should be sought. It should also be noted that atlanto-occipital, atlantoaxial, and coccygeal disrelationships with partial fixation place a degree of traction on the cord and dural sleeves in flexion-extension and lateral bending motions.

Cord Concussion

Immediate signs are usually not manifested in mild or moderate cord concussions; but weeks later, lower extremity weakness and stiffness may be experienced. Reason: It takes time for nerve fibers to degenerate. Deep reflexes become exaggerated and originally mild sensory, bladder, and rectal disturbances progress. The picture is cloudy, often mimicking a number of cord diseases (eg, sclerosis, atrophy, syringomyelia). Life is rarely threatened, but full recovery is doubtful. However, a patient's courage and determination can embarrass a doctor's negative prognosis.

Cord Contusions

If laceration occurs, shock is rapid. Deep reflexes, sensation, and sphincter control are lost. The paralysis is flaccid. Obviously, even a prognosis cannot be made until the shock is survived. Cord concussion usually complicates cord contusion.

Common Tests

Kernig's Neck Test. Biomechanically, this test is the cephalad representation of Lasegue's straight-leg-raising test. The supine patient is asked to place both hands behind his head and forcibly flex his head toward the chest. Pain in the neck, lower back, or down the lower extremities indicates meningeal irritation, nerve root involvement, or irritation of the dural coverings of the nerve root. That is, some lesion is being aggravated by tensile forces. When the examiner passively flexes the patient's neck and trunk, it is called the Soto-Hall test.

Kernig's Leg Test. The examiner flexes the thigh at a right angle with the torso and holds it there with one hand. With the other hand, the ankle is grasped and an attempt is made to extend the leg at the knee. If pain or resistance is encountered as the leg extends, the sign is positive provided there is no hip or knee stiffness or sacroiliac disorder.


DEVELOPMENTAL DEFECTS

Genetic factors frequently leave the lumbar spine unstable, and the gross and subtle implications of anterior-posterior, lateral, and rotational balance are manifold. The incidence of low-back disorders of a protracted and recurring nature is much higher in those whose spines show evidence of development defects and anomalies. This is especially true in the young. Such lumbosacral defects and complications as asymmetrical facet facing, imbrication, sacralization (especially the pseudo type), lumbarization, pars defect, discopathy, iliotransverse ligament sclerosing, retrolisthesis and L5-S1 reverse rotation are important concerns.

Body weight during development wedges the sacrum between the innominates because of their peculiar laterally inclined planes. This allows the sacrum to move inferiorly, anteriorly, and medially, coupled with the anteroinferior angulation of the sacral base. Many abnormal orientations found in the lower spine are because the lumbar facet joints are not determined until the secondary curves are developed in the erect position. Severe forces imposed during maturation contribute greatly to the high incidence of asymmetry.

SCREENING FRACTURES BY ROENTGENOGRAPHY

Acute injuries to the supporting soft tissues about a vertebra are rarely demonstrable in x-ray films. Their presence is suggested when the normal relations of bony structures are disturbed. However, when ligament lesions heal, hypertrophic spurs and sometimes bridges may develop locally on the margins of the bones affected.

Direct buttock falls upon a hard surface (eg, ice or roller skating, skateboarding) often result in vertical or sometimes oblique sacral fractures associated with other unilateral pelvic fractures, dislocation of the coccyx, and lumbar subluxations. After pelvic or leg injury, spontaneously reduced hip dislocation or consequent instability is sometimes missed. Note pelvic symmetry, deformity, and carefully palpate for bony crepitus about the ischium, rami, and hip areas.

Rolling injuries are usually at fault in pelvic ring fractures such as seen in horseback riding accidents, falls against a hard surface, and vehicular accidents. Vascular, bladder, and perineal injuries are often associated. Even when the ilium and/or sacrum are fractured, the strong sacroiliac joint usually remains intact.

Avulsions

The lower back and pelvis are common sites for avulsion-type injuries. Severe, sudden muscle contraction can produce fragmented osseous tears near sites of origin and insertion. Avulsions in the lumbar area often occur with transverse-process fragmentation at the site of psoas insertion. Although the transverse processes of the lumbar spine are quite sturdy, multiple fractures are seen in football and similar injuries.

Fatigue and avulsion fractures are far from uncommon, but typical injuries are associated with muscle, tendon, fascia, and cartilage injuries of the lower extremity. The common sites of avulsion fractures in one 2-year study occurred at the ischial tuberosity at the hamstring origin, the ASIS at the sartorius origin, and the AIIS at the origin of the rectus femoris muscle. In running strains, sudden severe pain in the area of the hip or buttock may be traced to an avulsion of the hamstring attachments at the ischial tuberosity. Roentgenography may indicate large crescent-shaped bone masses near the injured ischium.

Fractures

While pelvic fractures are not common, they should never be taken lightly as they are the second most common cause of traumatic death --second only to head injuries. They are usually due to violent injuries, are frequently multiple, and result in severe deformity. The most common area involved is about the sacroiliac joints and the symphysis pubis. A fracture or dislocation of a pubis is frequently associated with separation of a sacroiliac joint or fracture of the adjacent sacrum, ilium, or pubis.

Sources of Error. Colon or rectal gas on film may mimic or obscure a pelvic fracture, but as these shadows are not constant, they can be ruled out on future examination. Other sources of error are the blood-vessel grooves in the ilium, but their branching character and bilaterality help in identification. In examining the young, remember that the pelvic epiphyses are among the last to unite. They are open until 20--25 years of age.

Effects. Pelvic fractures often cause severe internal bleeding difficult to halt even on surgery. Shock is present in 40% of the cases. The patient is unable to stand or walk, complains of pain in the pelvic region or back. If the bladder or a kidney is injured, blood passes in the urine. A pelvic girth injury is suggested by severe low back pain (especially in retroperitoneal bleeding), severe pain with induced compression of the iliac crests, and acute pubic tenderness.

Transverse Process Fractures. Transverse-process fractures are frequently asymptomatic or nearly so and lack symptoms to encourage a most careful examination. As reported previously, lumbar transverse-process fractures are sometimes not evident or are poorly visualized in roentgenography (unless markedly displaced or angulated) because of overlying gas and/or soft-tissue shadows that obscure detail. A cleansing enema or other means of clearing overlying soft-tissue shadows is helpful whenever structures are not well visualized.

Ilium Fractures. Fractures of the ilium appear on film as sharply defined lines of diminished density that are possibly stellate.

Sacral Fractures. Sacral fractures are difficult to visualize unless there is some displacement. Isolated sacral fractures are invariably related to a direct blow from the posterior or the inferior. The mechanism of injury is sometimes associated with shear when a blow to the knee when sitting erect (eg, dashboard injury) drives the femur posterior, superior, and medial; rotation where the hip is severely hyperextended; and/or leverage where the A-P dimension of the pelvis is flattened. Fracture lines are usually through the sacral foramina, weakening the bone at these points.

Pubic Fatigue Fractures. On rare occasions, the adductor muscle attachment area at the inferior pubic ramus may be the site of overstress. This usually occurs from a fall or a sudden stop while delivering a bowling ball or throwing a heavy package in an unbalanced position. Avulsion of the inferior pubic ramus, rupture of the adductor longus' origin, and laceration to scrotal vessels may be associated.


ARTHROKINEMATICS

Static postural support of the lumbar spine in the prolonged relaxed erect or seated postures is provided essentially by the passive elastic tension of the involved ligaments and fascia rather than the spinal muscles whose roles can be considered insignificant during a state of relaxation. This shifting of support from the muscles to the ligaments, however, occurs slowly over a period of several minutes before significant EMG activity can be considered absent.



FUNCTIONAL ANATOMY OF THE LUMBAR SPINE

Body weight is carried in the lower back essentially by the L5 disc and dissipated to the sacral base, sacroiliac joints, and acetabulae. This weight on the L5 disc is forced slightly anterior on the load surfaces. The lateral line of gravity cuts a point just anteroinferiorly to S2. Weight distribution in the lumbar region is governed chiefly by the inclination of each vertebral body articulation. The lateral centerline of gravity falls on the spinal points because of gradual changes in the angles of the inclined planes of the various articular surfaces. This tends to force each lumbar vertebra more inferior, medial, and anterior or posterior until gravity brings the apex of the curve back toward the balancing point.

The Lumbar Facets

When the spine is in good alignment, facet articulation offers minimal friction. In scoliosis, the articular surfaces are no longer parallel and the result is articular scrubbing leading to impingement, erosion, and arthritis. This is the result of normally reciprocal articulating surfaces operating in an oblique position.

Lumbar Planes of Articulation. The lumbar facets are moderately sloped surfaces rather than a single-plane angle as seen in the cervical and thoracic area, and they are fairly parallel to the vertical plane at L1 and L2. The laterally convex inferior facets mate with the concave superior facets. From L1 to L5, the plane of the articular facets changes from mediolateral to anteroposterior and lie, for the most part, in the sagittal plane. There are considerable differences between the plane of articulation and the shape of the vertebral canal that progress from L1 to L5. Rotation and lateral flexion is anatomically inhibited by the articular planes in the L1--L2 segments but not in the L4--L5 segments. The upper lumbar joints appear J-shaped when viewed laterally, thus the anterior aspect of the articulations resists forward displacement.

Lumbosacral Facets. The lumbosacral facet planes are slightly more horizontal than those above, allowing greater A-P and lateral motion but less joint locking as compared to the vertebrae above. This horizontal and anterior inclination of L5, spreading out toward the coronal plane, becomes progressively more vertical upward from L4 to L1.

Facet Angle Variations. Interspinal posture is directed by the facet facing of each posterior intervertebral joint, with altered facings commonly occurring in the lumbar and lower cervical regions. Articular facings are altered more frequently between L4 and L5 than at any other level in the vertebral column. Normal symmetrical facets glide with little friction. However, if the facets deviate in their direction of motion, the unparallel articulations "scrub" upon one another. Over a period of time even in the absence of overt injury at the level of abnormality, articular variations present marginal sclerosis. This hardening is usually followed by hypertrophy or exostosis. Coexistent with this finding, the interarticular spaces gradually become narrowed, hazy, obscured, and even obliterated on x-ray films.


The Lumbar Intervertebral Foramina

Vertebrae move in the planes of their articulations, and it is at the posterior intervertebral articulations that subluxations occur and influence the IVFs. Changes in the diameter of normal IVFs parallel joint dysfunction that predisposes further subluxation and begins altering the curves of the particular region of the spine that this structural defect is found.

IVF Size and Shape. Lumbar IVFs are shaped laterally like inverted teardrops or kidney beans, with the diameter of the vertical axes about double the A-P dimensions. There is normally adequate space for changes in vertical dimension during normal movements without injury to the IVF contents as long as there is adequate fat and fluid present and stenosis and adhesions are absent. However, reduction of the already short transverse diameter can produce noxious effects. For this reason, mild disc collapse anteriorly is often asymptomatic, but a slight posterolateral herniation may protrude upon the IVF and produce severe symptoms.

IVF Contents. Each foramen widens and expands with spinal motion. From one-third to one-half the foraminal opening is occupied by the spinal nerve root and its sheath, with the remaining portion filled essentially by fat, connective tissue, and various vessels. The IVF contains the anterior nerve root, the posterior nerve root, a part of the dorsal nerve root ganglion, a bilaminar sleeve of dura and arachnoid membrane to the ganglion, a short continuation of the subarachnoid space with cerebrospinal fluid that ends just beyond the ganglion, the recurrent meningeal nerve, the spinal ramus artery, the intervertebral vein, and lymphatic vessels.

IVF Diameter Changes. Common factors altering the diameters of the IVFs are the disrelation of facet subluxation, the changes in the normal static curves of the spine, the presence of induced abnormal curves of the spine, degenerative thinning, bulging, or extrusion of the related IVD, the swelling and sclerosing of the capsular ligaments and the interbody articulation, and marginal proliferation of the vertebral bodies and articulations. These factors can insult the viable contents of the IVF. The result can be nerve root pressure, traction, or torque; constriction of the spinal blood vessels; intraforaminal and paraforaminal edema; induration and sclerosing of the periarticular ligaments with trauma to the receptors; forcing of the foraminal contents into protracted constriction and altered position; and such other consequences. It is not well recognized that acute phenomena are usually the result of friction, toxicity, and derangement from severe or repeated trauma, and encroachment from degenerative thickening or exostosis rather than of neurologic origin.

IVF Impingement. Lumbar nerve roots run anterior and superior to their facets. The root is often compressed in the IVF by a subluxated facet and less often by a herniated disc or a spur from the posterior aspect of the vertebral body. These disorders can be worsened by spinal stenosis that narrows the vertebral canal and the tunnel in which the nerve roots exit the IVFs.

Sensory Mechanisms. There are about twice as many sensory fibers than motor fibers in lumbar nerve roots. When the anterior root is irritated, pain is felt in the muscles supplied and often becomes self-perpetuating from the focal spasm produced. In posterior root irritation, pain can be felt in its dermatome, myotome, sclerotome, and possibly in the viscerotome.


The Lumbar Nociceptive Receptor System

The lumbar ligaments and fascia are richly innervated by nociceptive receptors. When the lumbar spine is in a relaxed neutral position, its nociceptive receptor system is relatively inactive. However, any mechanical force that will stress or deform receptors, with or without overt damage, or any irritating chemical of sufficient concentration will depolarize unmyelinated fibers and kindle afferent activity.

Importance of the Spinal Extensors

A strong correlation exists between spinal muscle strength and maximum lifting loads, and the spine withstands greater axial compression (eg, carrying a load) when the normal physiologic curves of the spine are maintained. Prolonged flexion postures and actions are frequently associated with the onset of back pain. It has been found that patients with back pain invariably have significantly weakened extensors as compared to asymptomatic subjects. EMG studies of patients show decreased extensor endurance during postural activities.

Even mild spinal extension unloads involved discs and allows fluid influx. This is important because IVDs need a state of low pressure to imbibe low molecular weight substances for proper nutrition. In addition, strong extensors reach fatigue slowly and are protective of spinal ligaments during light and unloaded activity.

In subjects not complaining of back pain, trunk extensor strength exceeds flexor strength and half of total spinal extension motion is produced by the erector spinae. Thus, this balance (erector strength) should be restored whenever necessary and maintained for both therapeutic and prevention goals.


POINTS OF GREATEST SPINAL STRESS

Motion at the Thoracolumbar Transitional Area

Because of restricted motion in the thoracic spine and the relatively A-P mobile lumbar spine below, the intervening thoracolumbar area must achieve a degree of hypermobility in all three body planes. Because of this, as is true to some extent in all spinal transitional areas, the thoracolumbar junction is more prone to stress from both above and below.

The superior facets of the transitional vertebra resemble thoracic facets and are designed for rotation and lateral flexion, even though these motions are restricted somewhat by the free ribs. While the stiff thoracic spine tends to move as a whole, most rotation takes place in the lower segments that are not restricted by the rib cage. The inferior facets of the transitional vertebra are of the lumbar type and designed for flexion and extension. Although we readily observe great curves in the lumbar area, most of the apparent rotation seen is from distortion of the lumbar spine's base, tipping, and the lumbar lordosis viewed out of its normal plane (ie, viewed obliquely).

It is controversial whether nerve roots are normally fixed to the margins of the IVFs. We can suspect that fibrotic changes following the granulation tissue of irritation, especially in the lumbosacral region, frequently fix the sleeve at one or more points. This contributes to traction on the sheath and its contents during movements such as in a straight-leg-raising test. These abnormal attachments increase in strength with repetitive trauma, aging, and other degenerative changes. Again we see the noxious effects of fibrosis.

Motion of the Transitional Lumbosacral Area

The coupling of L5 and S1 constitutes a rather unique "universal joint." For example, when the sacrum rotates anteroinferiorly on one side within the ilia, L5 tends to rotate in the opposite direction because of the restraint of the iliolumbar ligament. The effect is a mechanical accommodation of the lumbar spine above assuming a posterior rotation on the side of the unilateral sacral anteroinferiority. It also tends to assume an anteroflexed position, thus producing the three-dimensional movements of the lumbar spine. In view of the intricacy of the lumbosacral junction, anomalies such as asymmetrical facets have a strong influence on predictable movements in this area.

The iliolumbar ligaments connect the transverse processes of L5 to the crests of the ilia and sacral base. Aside from the articular facets, the iliolumbar ligaments appear to be the most important structures limiting axial rotation of L5 on the sacrum and preventing forward gliding of L5 on the sacrum. Because of its deep position below the iliac crests and the strong strapping by the iliolumbar ligaments and spinal extensors, L5 is only as movable as the sacral base will allow. Thus, when lipping of or spurs at the inferior L5 body are seen, a history of instability can be presumed.

KINESIOLOGY OF THE LUMBAR SPINE

Testing Muscle Weakness

The trunk is held erect by the flexors and extensors of the spine and the extensors of the hip. The muscles and ligaments holding the trunk erect are much stronger as a whole than those of the pelvis. After a long illness, for example, a patient can sit erectly long before he can stand unaided.

Flexion. Leg raising from the supine position is a two-phase combination between strong abdominals and strong hip flexors.

Extension. Because A-P trunk motions are the common movements used in daily living and as flexion is assisted by gravity, the spinal extensors are important muscles of the trunk from a biomechanical viewpoint. It is also for this reason that back muscles are rarely weak unless paralysis is present. Kendall places the incidence of weak spinal erectors at less than 1% in the nonparalytic. When signs of extension weakness are evident, differentiation must be made between weak spinal extensors and weak hip extensors.

Lateral Flexion. Trunk raising from the lateral recumbent position exhibits the strength of trunk lateral flexors and hip abductors.

Testing Muscle Shortening

The postural patterns exhibited in forward flexion from the supine position can offer distinct clues to shortening of specific muscles and muscle combinations.



KINEMATICS OF THE LUMBAR SPINE

If active lumbar motions are normal, there is no need to test passively. A patient may be observed, however, who replaces normal lumbar motion by exaggerated hip motion, or vice versa. The range of motion of the restricted lumbar or hip joints should then be passively tested. Any disorder of the hip joint itself (eg, fracture, tuberculosis, osteoarthritis, advanced necrosis, slipped plate) or of hip muscles may result in limited hip motion.

The range of lumbar motion is determined by the disc's resistance to distortion, its thickness, and the angle and size of the articular surfaces. As in the thoracic spine, the movements of the lumbar spine are flexion, extension, lateral bending, and rotation (minimal). While lumbar motion is potentially greater than that of the thoracic spine because of the lack of rib restriction, facet facing and heavy ligaments check the range of rotation.

Distortion Patterns

A feature of any spinal and pelvic distortion is that the segment or segments can be carried into the deviation of the distortion pattern more readily than out of the gravitational pattern of the deviation. Two examples illustrate this: (1) If there is a right structural scoliotic deviation of the lumbar area, the patient sitting, to fix the pelvis, will find it easier to rotate the torso to the right than to the left. (2) If there is a left wedging of L5, L4, or L3, lateral flexion to the left is noticeably easier than lateral flexion to the right.

The apices of curves and transition areas are logical points for spinal listings since they are frequently the location of maximum vertebral stress. Subluxations may occur at other points in curves and rotations, particularly at the beginning point of a primary defect in balance such as in the lower lumbar and upper cervical sections. Subluxations frequently occur also at the point where a primary curve merges into its compensatory curve.

A posterior L3 is rare when the apex of the lumbar curve is too high or too low, but common at L4, L5, and the sacral base. When the apex of the lumbar curve is too low, a posterior subluxation will most likely be found in the upper lumbar area.

Lumbosacropelvic Rhythm

Forward flexion takes place in two phases. During the first 60° of flexion, the pelvis is locked by the posterior pelvic muscles. About 70% of this motion occurs at the lumbosacral joint, 20% between L5--L4, and 10% between the L1 and L3 vertebrae. This motion is smoothed by the counterforce of the spinal extensors. During the second phase, from 60° to 85° , the hip releases and the pelvis rotates bilaterally forward around the transverse axis of the hip joints. Near the end of spinal flexion, the sacral base slightly follows L5 anteroinferiorly as the sacral apex pivots posterosuperiorly.

Synchronization of these lumbar-sacral-pelvic motions must be achieved to obtain minimal biomechanical stress. Abnormalities in these mechanisms will quickly point out and help differentiate sites of lumbar, sacral, or hip restrictions or instability.

The Revealing Adams Position

This important test should never be supervised casually. It was a crucial tool in pioneer chiropractic that appears to be depreciated in today's education. The reader should weigh the large array of clinical clues brought out below.

The patient assumes the Adams position by standing erect with the heels together, then bending forward with the fingers as near the floor as possible without straining. For an indication of gross spinal flexibility, the distance between the fingertips and the floor can be measured or at least observed. In bending, the knees should not flex. As a patient advances in age and the spine settles, there will of course be less flexibility. Stiffness would also occur with taut or spastic paravertebral muscles.

During lower back flexion or extension, there is far less vertebral gliding than seen in other areas of the spine during A-P motion. Opening of the anterior disc space on extension or of the posterior disc space on flexion does not occur until movement nears its full range of motion. Even then, it is much less than that seen in other areas of the spine. The anterior longitudinal ligament relaxes during flexion, and the supraspinal and interspinal ligaments stretch. Forward flexion in the adult will not normally result in a kyphosis of the lumbar area as it does in the cervical area. While a number of disorders result in decreased flexion, paraspinal muscle spasm is the prime suspect.

Gross Observation

While the patient moves in and out of the flexed Adams position, the following points are noted:
(1) Is flexion unrestricted?
(2) Is flexion straight forward or deviated laterally?
(3) Do spinous processes line up straight during forward flexion and extension from flexion? This is more easily determined by dotting the spinous processes with a skin pencil when in the standing position.
(4) Are there abnormal prominences or movements of the angles of the ribs during A-P motion? Is the pelvis level?

The two most common clinical signs that appear are (1) restriction of end motion (motion block, with or without pain) in which the patient's fingers stop far above the floor, and/or (2) scoliotic rotation of the spine in which the vertebral bodies follow the plane of least resistance (structural or antalgic).

Segmental Faults

As the patient moves into and out of the Adams position, the vertebral column should be examined for individual segments that flatten or arch at the wrong time or do not move evenly with their neighbors. Palpation should be done with the fingerpads on the interspinous spaces. With motion by the patient, the various segments of the spine can be felt to glide closer together or further apart. Should an area be found that remains rather immobile or without the normal gliding action, further tests and x-ray studies should be made of this section of the spine.

Standing Forward Flexion

During the first stage of flexion, the normal lumbar lordosis gradually flattens and then gradually develops a smooth curved kyphosis. The degree of lumbar flexion in many people is up to and only slightly over the flattening of the normal lordosis, thus total possible flexion must be achieved by hip rotation. In fact, some people can bend forward to touch the floor with little change in the spinal curves. This is usually due to hypermobile ilia and hips adapting to lumbar fixation. If the lumbar curve fails to flatten during trunk flexion, the first suspicions should be restriction of the posterior elements from muscle contraction, ligament shortening, or abnormal articular planes.

Unilateral facet asymmetries will often be revealed by a distinct scoliosis exhibited in the Adams position that is not apparent in the erect position. If pelvic rotation fails to occur, the first suspicions should be effects of sciatic irritation, hip restriction, or tight hamstrings. If a hamstring fails to elongate unilaterally, distinct contralateral lumbar rotation will be seen during flexion as L5 follows the low sacrum.

Supine Hyperflexion

In this adaptation to the standing test, the supine patient is asked to grasp his flexed knees, pull them toward his abdomen, and flex his neck forward in an attempt to touch his forehead between his knees. In this position, flexion should occur from below upward and a greater stretch is placed on the lumbosacral area than can be achieved in the standing position. The examiner's fingertips can be placed in the lumbar interspinous spaces to evaluate segmental motion. At the same time, the examiner should note the maximum range of motion and the production, increase, or reduction of pain and its distribution. Before concluding this part of the examination, the examiner should test the effects of repetitive loading.

In contrast to forward flexion in the standing position, flexion in the supine position places little tension on the sciatic nerve. Thus, sciatica aggravated by both standing and supine flexion suggests a disc involvement. Sciatica aggravated in the standing but not the supine position suggests a nerve root involvement.

Extension

Extension occurs from above downward. The maximum range of motion, and the production, increase, or reduction of pain and its distribution should be noted. Testing can be considered a reversed Adams maneuver.

The posterior portion of the anulus is the weakest. The anterior and lateral aspects are almost twice as thick as the posterior aspect. The anular fibers at the posterior aspect of the disc are less numerous, narrower, and more parallel to each other than at any other portion of a lumbar disc. If a person must work habitually in a prolonged forward flexed position, periodic lumbar extension will relieve the stress of the posterior anulus and tend to shift a loose nucleus pulposus anteriorly; ie, away from the spinal cord and IVF. Many manual workers do this maneuver unconsciously.

Standing Hyperextension

To test lumbar extension, the standing patient bends backward as far as possible and given support by the examiner placing one hand firmly on the patient's sacrum and the other hand on the patient's anterior chest. The degree of extension is controlled by stretching of the anterior longitudinal ligament and rectus abdominis, relaxation of the posterior ligaments, and contraction of the spinal extensor muscles. The examiner's fingertips can be placed in the lumbar interspinous spaces to note segmental motion. If posterior disc protrusion, facet inflammation, or spondylolisthesis exist, pain will be increased during extension. Before concluding this part of the examination, the examiner should test the effects of repetitive loading.

Impeded Extension

Loss of lumbar extension is often the result of poor sitting posture and/or inadequate extension mobilization following injury in which shortened scar tissue prevents a full range of extension. Reduced extension (1) causes chronic posterior stress on the soft tissues of the vertebral motion unit and an increased intradisc pressure during sitting; (2) restricts a fully upright posture during relaxed standing, leading to a stooped appearance in stance and gait; and (3) produces a premature fully stretched lumbar posture when arising from a forward flexed posture. Restricted extension is usually the result of fixation at the posterior aspect of the motion unit that prevents facet gliding. Increased pain during hyperextension suggests a rotational subluxation. When a posterolateral herniation is present, the patient will have restricted extension with deviation away from the side of pain.

Standing Extension from Flexion

Just as much information can be gathered as the patient returns to the neutral position as during flexion. If a load is being lifted, the majority of the force is on the posterior lumbar ligaments until about 60° when the back muscles become active and the abdominals serve to smooth the action. The main function of the longitudinal ligaments is to restrict abnormal motion. If there is segmental restriction, excessive motion is forced on the adjacent segments and the hips. Hip restriction forces excessive motion on the lumbar spine and sacrum. If there is excessive joint laxity, subluxation with or without sprain or strain may occur.

The most common fault recognized in extension from full flexion is premature return of the lumbar lordosis. If this occurs, the first suspicion should be weak hamstrings and/or other pelvic extensors. Associated weak abdominals will contribute to faulty pelvic stabilization.

Recumbent Hyperextension

A patient's spine is automatically placed in extension when the prone position is assumed on a flat surface. The prone patient is asked to lift his trunk upward by extending his elbows, yet keeping his lower pelvis firm against the examining table. This is similar to a push-up where the pelvis is not raised.

A much greater degree of lumbosacral hyperextension can be achieved in the prone position than in the standing position. As in the other tests, the examiner's fingertips can be placed in the lumbar interspinous spaces to note segmental motion and the maximum range of motion and the production, increase, or reduction of pain and its distribution should be evaluated.

A small disc protrusion would be reduced by segmental extension, thus extension should relieve pain. However, an entrapped fragment or protrusion would not be benefited and may be aggravated. Before concluding this part of the examination, the examiner should test the effects of repetitive loading.

Standing or Sitting Lateral Flexion

In the lumbar spine as a whole, lateral flexion is relatively free, followed in order of mobility by extension, flexion, and minimal rotation. Most significant to movements in the lumbar spine is that all movements are to some degree three dimensional; ie, when the lumbar spine bends laterally, it tends to also rotate posteriorly on the side of convexity and assume a hyperlordotic tendency. Testing can be considered a lateral Adams maneuver.

In evaluating lateral flexion of the lumbar spine, the standing or seated patient's right iliac crest should be stabilized as he leans to the left as far as possible. Then the same maneuver is repeated for the other side, and the degree of lateral flexion is noted. The standing patient is asked to flex sideward and move his hand on the side of bending distally down the side of his thigh as far as possible. This point should be recorded. Lateral flexion should occur from above downward. The examiner's fingertips can be placed in the lumbar interspinous spaces to evaluate segmental motion.

The maximum range of motion and the production, increase, or reduction of pain and its distribution should also be evaluated. It is not unusual to find that one side is unrestricted and the other side is blocked. This suggests a degree of scoliosis, with restricted movement on the side of convexity. A laterally displaced nucleus pulposus would have the same effect. Before concluding this part of the examination, the examiner should test the effects of repetitive loading.

During lateral bending in the erect position, considerable rotation accompanies abduction motion if there is a significant degree of lordosis. However, if the lumbar spine is relatively flat or if the lateral bending is performed in the sitting position, the amount of rotation is minimal. The intertransverse spaces of the normal spine open on the convex side and approximate on the concave side. In distinct lordosis, however, the facets are relatively locked and lateral flexion is so restricted that the vertebrae must severely rotate to allow significant lateral bending.

Rotation

To grossly screen trunk rotation, the standing or sitting patient's pelvis is stabilized and he is asked to turn his shoulders as far as possible to the left and then to the right. Only a slight degree of rotational fixation is necessary to affect A-P and lateral bending motions. Because the facial planes are no longer reciprocal, normal motion becomes restricted.

Axis of Rotation

If the axis of rotation of lumbar vertebrae were at the tips of the spinous processes, as sometimes is taught, the spinous process of L1 would be directly in line with the process of L5 during rotation while the vertebral bodies rotate to a greater degree toward the direction of movement. But because the center of rotation of T12 is distinctly anterior, it must pull L1 with it during rotation. This forces the lumbar region into rotation and flexion that jams the facets on the side moving posteriorly and opens the facets on the side moving anteriorly. This lumbar effect is continued to the sacrum, which also flexes and rotates with the lumbars.

Rotation During Flexion

When the spine does not bend straight forward during flexion (Adams position) but deviates to one side, even slightly, a search should be instituted for contractured, thickened, or shortened muscles, tendons, and/or ligaments of the column existing on one side and not on the other. If the spine shows rotation to the right, the patient in a forward bent position can swing his torso into right rotation more readily than to the left.

In common pelvic mechanical pathologies on the side of involvement, there are an observable slanting and anteriority of the pelvis in the forward bending position. There will be a noticeable lumbar scoliosis to the side of involvement. Elevation or prominence of the ribs on either side denotes a rotation of the vertebrae on their axes. Shortening of the ligaments with contracture of the muscles of the spine exhibit as abnormal stiffness or hardness of the muscles on the side of the spine that suffers from contractures. The examiner should compare the position of the dots over the spinous processes with their appearance when the patient was in the anatomical position.

Loading

The importance of spinal load is underscored with weight lifters, bowlers, oarsmen from lifting the shell, and even in lordotic long-distance runners. When an object is held 14 inches away from the spine, the load on the lumbosacral disc is 15 times the weight lifted. Lifting a 100-lb weight at arms' length theoretically places a 1,500-lb load on the lumbosacral disc. This load, of course, must be dissipated, otherwise the L5 vertebra would crush. The load is dispersed through the paraspinal muscles and, importantly, by the abdominal cavity acting as a hydraulic chamber absorbing and diminishing the load applied. This emphasizes the vulnerability of the spine to the mechanical stresses placed on it, especially in people with poor muscle tone. Bony compression of the emerging nerve roots arises as a result of subarticular entrapment, pendicular kinking, or foraminal impingement due to posterior vertebral subluxation.

Effects of Repetitive Loading. Repetitive loading has beneficial effects on shortened tissues and adverse effects on the disc or an area of inflammation (eg, sciatic neuritis). To test the effects of repetitive lumbar flexion loading, the standing patient is asked to flex forward to the maximum and return to normal ten times in succession. If the patient's pain increases, a disc involvement or area of inflammation is presumably the factor involved. If the patient's pain reduces, shortened tissues are most likely the origin of the patient's pain.



FUNCTIONAL ANATOMY OF THE BONY PELVIS

The pelvic basin is the anatomical link between the axial skeleton and the lower extremities. Although the hip joint is anatomically considered part of the lower extremity, it is so closely linked biomechanically to the sacrum and lumbar spine that it must be considered in any discussion of the pelvis.

The common pelvic landmarks are the anterior superior iliac spine (ASIS), posterior superior iliac spine (PSIS), and the anterior inferior iliac spine (AIIS). The summits of the iliac crests are normally on a level with the L4 spinous process, and the PSISs are on a level with the S2 spinous and near the midline of the lower third of the sacroiliac articulation. However, pelvic design differs greatly among sexes and biotypes. In addition, there are wide individual variations, and asymmetry is more the rule than the exception. Thus, static palpation alone can lead to many erroneous conclusions.

The Iliac Facets

Anterolateral to the PSISs and PIISs of the ilium are the convex facets that articulate with the sacrum bilaterally. As they resemble rough bony ears facing backward, they are called auricular surfaces. Some call them boot-shaped, with the toes pointing backward. Regardless, they are slightly wider than their mates on the sacrum. Boorsma describes this boot-shaped articular design as relatively deep, oblique, mobile, and especially related to a hyperlordotic spine. When associated with a chronically flattened lumbar spine, the sacroiliac articulations are more bean-shaped, vertical, shallow, and less mobile.

The short arm or foot of each articulation allows a sliding motion anterior-inferiorly or posterior-superiorly and a rotating action about the pit. The foot of the boot articulates with the S2 and S3 segments. This design has a distinct influence on traumatic iliosacral motion. The upper pit also serves to giver osseous relief to the relatively weak superoanterior ligaments. An important role of this design is to prevent sacral displacement during loaded movements. Superior and posterior to the articular surface is a larger area of rough bone serving for the attachment of strong sacroiliac ligaments.

The Sacrum

To meet with the flared ilia, the S1--S3 segments are wider anteriorly than posteriorly. The concave sacral articulation with each ilia is congruently boot-shaped, and its numerous bumps and depressions offer stability and limit motion. These ridges and furrows, however, are not always ideally reciprocal with those of the ilium, nor are the bilateral planes of articulation commonly symmetrical. This leads to erroneous conclusions during heel checks for functional leg lengths.

The Ischia and Pubic Bones

The body of the inferior ischium serves as the posterior half of the lower two-thirds of the acetabulum. The ischial ramus forms the posterior wall of the lower pelvis and the inferior wall of the obturator (closed) foramen. This foramen, although seen as a large opening in the dried skeleton, is completely closed in vivo by a tough membrane to which several strong muscles are attached to the circumference of the opening.

The Sacroiliac Joints

With the bony architecture of the sacroiliac articulation in mind, we turn to their syndesmology. Here we find slightly sliding, gliding, pivoting, and rotating sacroiliac joints that serve as the sole point where the axial skeleton is attached to the pelvis. Thus the necessity of these joints being bilaterally strong. They are uniquely both diarthrotic and amphiarthotic. The inferior two-thirds of the joint is a true synovial articulation. The superior third is a fibrocartilaginous amphiarthrosis supported by the short but strong sacroiliac ligaments. Thus, a true polysynovitis can involve only the caudad aspect of the joint even though synovial membrane covers the whole joint cavity except its posterior aspect where large ligaments attach to articular cartilage.

Major Ligaments

Excessive motion is strapped posteriorly by the interosseous ligaments, the short posterior sacroiliac ligament on the superolateral aspect of the sacrum, the long posterior sacroiliac ligament, and the sacrotuberous ligament on the inferolateral aspect of the sacrum. White/Panjabi state that the interosseous sacroiliac ligaments supporting the thin fibrous capsule posteriorly and inferiorly are the strongest of the body. These ligaments, the chief bond between the sacrum and ilia, are so thick that they fill the roughened space between the sacral and iliac tuberosities behind the sacroiliac joint. There is an upper part spanding between S1--S2 and the anterior medial iliac crest. Immediately below is the lower part of the ligament arising from S3 that inserts into the iliac crest.

The strength of these ligaments helps prevent displacement of the sacrum even during forceful jumping. The major straps anteriorly are the thinner anterior sacroiliac ligaments on the superolateral aspect of the sacrum and the stronger sacrospinous ligament extending from the inferolateral aspect of the sacrum and coccyx to the ischial spine. The superolateral ligaments appear to be little more than extensions from the anterior capsule. Varieties of interarticular adhesions appear within the joint with age, but they are not reported to restrict motion.

It has been widely reported that Illi found an interarticular ligament at the toe of the boot in the 1950s that he believed has a considerable influence on sacral motion. In fairness, an identical ligament was reported by Dr. Pfitzer [spelling is from the author's 40-year recall], professor of Anatomy at Lincoln Chiropractic College, in the 1940s.

Major Muscles

Strong muscles surround the joint, but there are no intrinsic muscles as seen in the spine. Muscle action is indirect via ilia, ischia, hip, and lumbar attachments. Nevertheless, several muscles have close association with sacral ligaments. For example, (1) fibers of the lower quadratus lumborum mix with the iliolumbar ligament; (2) fibers of the iliopsoas mingle with the anterior sacroiliac ligament; (3) fibers of the multifidi and sacrospinalis braid with the long posterior sacroiliac ligament; (4) fibers of the gluteus maximus and hamstring fibers intertwine with the sacrotuberous ligament; and (5) fibers of the piriformis mix with the sacrotuberous ligament and some enter directly into the sacroiliac capsule.

Innervation

Segmental innervation from the lumbosacral spine is shown in Table 1. The gluteus maximus receives an independent nerve (inferior gluteal) from the sacral plexus that leaves the pelvis below the piriformis muscle close to the lateral edge of the sacrotuberous ligament. This nerve and accompanying inferior gluteal artery and vein pierce the gluteal fascia and then spread between the fascia and the muscle. The gluteus medius is supplied by the superior gluteal nerve and vessels that exit the pelvis above the piriformis muscle.

Table 1. Segmental Innervation of the Lumbosacral Spine

Segment	Major Muscles Supplied
L1-2	Cremaster
L1-5	Iliopsoas
L2-3	Sartorius, pectineus, abductor longus
L2-4	Quadriceps, gracilis, adductor brevis
L3-4	Obturator externus, adductor magnus and minimus
L4-5	Tibialis anticus
L4-S1	Semimembranosus, semitendinosus, extensor hallucis longus, popliteus, plantaris, extensor digitorum longus, extensor hallucis brevis, gluteus medius and minimus, quadratus
L5-S1	Peroneus longus and brevis, tibialis posticus, flexor digiti brevis, abductor hallucis
L5-S2	Gluteus maximus, obturator internus, biceps femoris, soleus, gastrocnemius, flexor hallucis longus
S1-2	Lumbricals, piriformis, abductor digiti, flexor digiti, opponens, quadratus plantae, interossei
S2-4	Levator ani, bulbocavernosus, ischiocavernosus
S4-5	Sphincter vesicae
S5-Cx1	Sphincter ani, coccygeus
	Skin-Reflexes
L1-2	Cremasteric
L4-S1	Gluteal
S1-2	Plantar
S5-Cx1	Anal
	Tendon Reflexes
L2-4	Patellar
L5-S2	Achilles

Active Sacroiliac Motion?

Although there are no intrinsic muscles of the sacroiliac joints, the intermingling of muscle fibers in the ligaments described above allows the ligaments to serve somewhat as tendons. Thus, not all sacroiliac motions need to be considered purely passive as is so commonly taught. This point is underscored by the discovery of mechanoreceptors, reported by Denton, throughout the sacroiliac ligamentous complex that are similar to Golgi tendon organs.

Innervation and Referred Pain

The posterior aspect of the joint is supplied by the posterior rami from L5--S2. An irritation in the posterior joint usually refers pain to the buttocks and back of the thigh, following the dermatomes. The anterior aspect of the joint is supplied by both posterior branches from the L3--S2 roots and the superior gluteal nerve (L5--S2). Anterior joint irritation commonly refers pain to the groin and anterior thigh. If the sciatic nerve pierces the piriformis rather than exiting the pelvis over or under the muscle, sacroiliac distortion or inflammation can involve any of the numerous sciatic fibers.


SACROILIAC DYSFUNCTION

There are three articular areas of primary concern in adult sacroiliac dysfunction:

    · An iliac elevation and sacral depression in the upper third of the joint.

    · An iliac depression and sacral elevation in the middle third of the joint.

    · An iliac elevation and sacral depression in the lower third of the joint.

Load Carriage Effects

By puberty, in adaptation to walking and other stresses, all articulating surfaces develop a variety of incongruities and small projections where dynamic stress would be concentrated if not for the smoothing effect of articular cartilage. Of all articulations, the adult sacroiliac joint contains a large array of reciprocal bony hills and valleys. This surface roughness, more prominent in males, is generally considered the result of its segmental heritage; ie, the fused lateral tips of the transverse processes and the intertransverse spaces.

The characteristic of a roughened articular surface allows deformation during loading to increase the contact area and significant recovery during the unloaded stage. Load carriage is particularly enhanced by the cartilage's hydrophilic proteoglycans to retain matrix water and by collagen to resist matrix tensile forces.

Sacroiliac stability is so great that experimental overloading of S1 results in fracture of the lateral sacrum, pubis, or hip while the sacroiliac joints remain intact. Thus, complete fractures or greatly advanced destructive processes are the common causes of clinical instability of the sacrum.


THE SACROCOCCYGEAL JOINT

The atypical joint between the sacrum and coccyx is considered a symphysis. It is united by a rudimentary IVD and tough ligament bands around its circumference. Slight posterior motion normally occurs during defecation, gait, and much more so during parturition.


THE SYMPHYSIS PUBIS

The anterior aspect of the hyaline coated pubes join at the fibrocartilaginous pad (anuclear disc) of the pubic symphysis. Slight but important movement takes place at this joint by yielding of the interpubic fibrocartilage. Iliac motion imposes reciprocal compression, tensile, and torsional forces on the pubes. Excessive movement is strapped by the superior and inferior pubic ligaments, and fusion is rare even in old age. Pubic innervation is by L1--S4 fibers. Referred pain is diffuse or unpredictably specific.


APPLIED PELVIC KINEMATICS

The pelvis and its articulations are located fairly central to the kinematic chain extending from the cranium to the feet. Thus, any alteration in normal dynamics such as a unilateral fixation must manifest biomechanical effects both above and below. Fixation at a link or links of any kinematic chain forces hypermobility on the nearest mobile segments.

Within the lumbar spine, Illi located the axis of rotation posterior to the articular facets. This permits a wide range of vertebral body rotation, restricted essentially by the facial planes and the paravertebral ligaments.

The inclination of the sacral base directs the lumbar curve. However, the axis of movement of the thoracic spine lies far anterior to the facets: near the nucleus of the L5 IVD. Thus, thoracic rotation is characterized by deviation of the spinous processes in a wider arc than that taken by the vertebral bodies.

Coupling Dynamics

The thicker anterior and thinner posterior aspects of the lumbar discs provide the lumbar spine with its unique rotation, lateral bending, and combined phenomena. The coupled lateral bending and rotation of the lumbar spine during forward flexion (1) protects the axial length of the lumbar spine and its contents from excessive tension; and (2) causes the peripheral fibers of the anulus to draw inward, thus securing the nucleus more firmly as a protection against displacement.

Effects of Inhibited Coupling

Coupling helps to explain why fixation-inhibiting rotation during flexion invites IVD protrusion. If rotation is not freely allowed during flexion, the segment tends to slide laterally and produce excessive shear forces upon the subjacent IVD and posterior facets. These basic characteristics of the lumbar spine coupled with the mechanics of the ilia are the primary factors governing sacral dynamics.

Pelvic Tilt and Horizontal Rotation

In the neutral position, the ASISs normally lie in the same transverse plane and in the same vertical plane as that of the symphysis pubis. The movements of the pelvis as a whole are forward and backward tilt around the transverse interfemoral axis, lateral tilt (associated with lumbar scoliosis), and rotation in the horizontal plane. None of these motions are produced by intrinsic pelvic muscles; rather, they are made by muscles of the trunk and hip that attach to the pelvis or sacrum. These motions occur at and affect the lumbosacral junction, the heads of the femurs, and the sacroiliacs to a far lesser extent.

Common Determinants of the Lumbar Curve

A-P Tilt. Forward and backward pelvic tilts describe an arc that appears to follow the arcuate (bow-shaped) ridge and groove of the sacroiliac facets. Forward tilt is related to lumbar hyperlordosis and hip flexion. The anterior thigh muscles are also a strong component in this motion, and thus the frequent involvement of these muscles in pelvic distortions. Backward tilt is associated with lumbar flattening and hip extension. The major actions come from the posterior pull of the hamstrings and the anterior pull of the rectus abdominis with help from the obliques.

Lateral Tilt. When a person shifts most of his weight to one leg, passive lateral pelvic tilt occurs. The pelvis on the unsupported side is restricted actively by the gluteus medius and minimus and passively by the iliotibial tract of the fascia lata. When weight is distributed bilaterally, lateral tilting of the pelvis is associated with lumboscoliosis, sacroiliac distortion, or a unilateral short leg.

Rotation. Axial or lateral rotation of the pelvis about a fixed femoral head is produced by actions of the muscles of the thigh, loin, and the abdominal obliques. This is exhibited in walking.


SACROILIAC MOBILITY

It was an allopathic "fact" for many years that there was no normal sacroiliac or pubic motion in the absence of disease and that the sacrum and ilia moved as a whole. This position has long been disputed empirically by chiropractic and osteopathic physicians and in recent years been proved a fallacy through cineroentgenographic studies. Only since the 1970s has sacral motion been generally recognized in allopathic literature.

Illi believed that a human being is the only vertebrate with a movable sacroiliac articulation. At birth, the joint is only slightly movable. Due to bipedism, sacroiliac function is produced. However, because the sacroiliac and pubic articulations are readily subject to fixation, normal movement is not always found in the adult of modern society where physical activity is often minimal. Nevertheless, several autopsy studies report freely movable joints in individuals over the age of 80.

Multidirectional Mobility

Slight but smooth motion occurs upward, downward, forward, and backward through middle age, and axial rotation occurs around a transverse axis to allow pelvic tilting. Because the sacrum does not have distinct articular planes but moves within the pelvic ring, its motion is multidirectional for 1--3 mm rather than in restricted directions. This multidirectional mobility of the sacrum is likely the result of the wider iliac facet, the longer sacral facet, and the thick articular cartilage of the sacrum.

This multidirectional action is especially passive in the nonweight-bearing positions and affected above from lumbar forces and/or laterally and below from iliac-ischial forces. In vivo, sacrum-ilia movements are always coupled and there is no one normal movement of the sacrum on the ilia.

Gillet's Classification. Intrapelvic mobilities were classified by Gillet into three categories: (1) the A-P rotations of the ilia in relation to the sacrum, and to each other at the pubis, (2) the various movements of the sacrum itself in relation to the ilia, and (3) the sitting-standing changes in the relationship of the ilia to the sacrum and to each other.

Another motion of the sacrum is at the lumbosacral joint where it moves passively with the ilia such as seen in lateral flexion of the pelvis during gait. Weisl, Gonstead (see Campbell JR), and others also give an inferior or superior gliding motion along the caudal aspect of the sacroiliac facet.

Sacral Changes from Recumbent to Standing Positions

Several studies show there is distinct sacral motion in changing position from the recumbent, to the sitting, to the standing postures. The sacrum approaches its nearest state of static equilibrium in the prone position where inferior and superior forces are significantly removed. This could be an explanation why sacral and para-anal reflex techniques achieve their effect in this position.

General Sacroiliac Motion During Pelvic Tipping.

During forward flexion of the trunk in either the standing or sitting position, the sacral base pivots further anteriorly and inferiorly while the sacral apex moves posteriorly and superiorly. Simultaneously, the PSISs move posteriorly, inferiorly, and obliquely medially so that the space between the spines reduces. The ischia concurrently move obliquely anteriorly, superiorly, and fan laterally. During extension, these pelvic actions are reversed.

Standing A-P Sacroiliac Motion

During erect weight bearing, the sacral base tends to rotate (pivot) anteriorly and inferiorly about the lateral S2 tubercles. When the standing patient lifts his right knee to a maximum, as in taking a high step, the right ilium tends to follow the femur's motion, rotating in the A-P plane with the center of movement near the femoral head. At the same time, the right arm of the pubis moves upward relative to its opposite. This is palpable. The iliac portion of the sacroiliac articulation glides posteriorly and inferiorly relative to its contact with the sacrum. Thereafter, the sacrum must arc posteriorly and inferiorly with the left ilium.

If both the pubic and sacroiliac articulations reach their limit of mobility and the knee is lifted still further, the pubis starts serving as the center of rotation and, at the posterior pelvis, the ilium will start pulling the sacrum down in its course, forcing it to articulate with the opposite ilium. As this latter motion does not follow the sacroiliac facet plane, a certain degree of joint separation takes place. If the knee-lifting test is carried still further, the normal limit of the other articulation (the left in this example) will be reached, and then the whole pelvis rotates backward.

Note: In the standing position, motions of the sacrum relative to the ilia are sometimes difficult to detect because of coupled acetabular changes, thus it may be necessary to seat the patient to restrict these movements. Sitting fixes the pelvic base, alters its shape, and permits a totally different type of motion than that of the standing position.

Sitting Sacroiliac Rotational Motion

In the sitting position, the sacrum readily flexes and turns between the ilia. To produce this movement, the stabilizing arm of the examiner grasps the opposite shoulder of the patient across his chest and rotates the patient to a maximum while the examiner's palpating fingers follow the sacral spinous processes in their movement. The lumbar region also rotates and flexes to follow the line of the thoracic vertebrae that move laterally in a wide arc. The placement of the sacrum can also be roughly judged by the direction of the buttock line.

There is a fundamental difference between A-P standing mobility of the ilia on the sacrum, which does not carry the sacrum with it until the limit of movement is reached, and the rotation and flexion of the sacrum in the sitting position, which carries the ilia with it to a degree. This partial iliac mobility in the sitting position can be palpated by placing the thumb on the crest or on the PSIS and following it forward and downward as the thorax rotates in that direction. Most authorities agree that any degree of sacral rotation has a related translatory component.

Sacroiliac Motion During Lateral Flexion

In lateral flexion, a similar movement of the sacrum takes place with a maximum of flexion and a minimum of rotation. To feel this, the shoulders of the patient must be put into a complete lateral bending posture and an attempt made to concentrate the movement in the area palpated. Again, the ilia attempt to follow this movement into lateral flexion, with the distal ilium flaring away.

Sacroiliac Motion During Gait

Sacroiliac motion allows for reciprocal movement of the innominates and a gyroscopic motion of the sacrum during gait. These motions tend to dampen the axially directed forces of heelstrike. Illi showed that as the heel strikes, the ilium rotates posteriorly and inferiorly, the sacral base rotates anteriorly and inferiorly, and the ipsilateral transverse of L5 is pulled backward. This vertebral action of functional lumbar scoliosis diminishes cephally. At midstance, the pelvis moves over the femoral head in a neutral position. As the contralateral extremity is abducted forward, the sacrum is positioned posteriorly and superiorly on that side.

This reciprocal motion between the sacrum and ilium describes a horizontal Figure-8 between the ilia when viewed during gait. One side of the sacral base arcs downward and forward and rotates toward the ipsilateral side. The other side swings upward and backward and the sacral apex rotates toward the contralateral side. The path of this arc appears to be the product of sacral translation and torque having various components, depending on the planes of the bilateral facets, the force vectors, and the bilateral integrity of the involved restraining ligaments.

Sacral Motion During Respiration

The majority of references to the sacral-respiration mechanism have been published by DeJarnette, Goodheart, and a number of osteopaths researching cranial manipulation and reflexes. They found that there is a slight sacral A-P motion during respiration and Valsalva maneuvers. The sacral base tends to pivot posteriorly during inspiration (or increased intra-abdominal pressure) and anteriorly during expiration from 1 to 7 mm. The rate is about 14 excursions per minute.

This sacral mechanism, synchronized with a reciprocal cranial action, is reported to produce a pumping action on cerebrospinal fluid circulation. This is explained by the continuous dural sheath that descends from the cranial vault, attaches at the foramen magnum, connects to the posterior ring of the atlas and odontoid, and then descends through the spinal canal to insert near S2. This theory helps to explain why sacral and upper cervical dysfunctions are so frequently associated.

Pelvic Changes During Sitting and Standing

In sitting postures where weight is borne essentially by the ischial prominences, the body tries to widen its base of support by slightly separating the ischia, which, in turn, slightly close the iliac crests. As the inferior sacral space opens, the apex of the sacrum juts backward to remain in contact with it. That is, because of the oblique slant of the sacral facets, the sacral base moves anteriorly and the apex moves posteriorly. The axis of this motion is commonly a horizontal plane approximately at the S2 level. Articulation for this motion takes place at the pubic and sacroiliac articulations.

A different mechanism is seen in the standing posture. On arising, the ischia are passively brought together to permit body weight to lie directly on the heads of the femurs. It is then that the iliac crests open laterally (flare out). This closes the inferior sacral angle, opening the space that holds the base of the sacrum. In adaptation, the sacral base moves slightly posteriorly, and the apex nutates anteriorly.

In considering A-P nodding of the sacrum, remember that the positions of the ilia are not rigid and that the slant of the articulations forces the ilia to adapt themselves to flexion by lateral flexion of their own. Thus, we rotate each hip backward and forward each time we walk. Each time we sit and arise, we cause our ilia to flare outward and inward. Each time we bend or turn in a seated position, we cause the sacrum to move within the interiliac space. Yes, the sacrum is the dynamic foundation of the spine.



CLINICAL MANAGEMENT ELECTIVES FOR LOW BACK STRAIN/SPRAIN

1. Stage of Acute Inflammation and Active Congestion

The major goals are to control pain and reduce swelling by vasoconstriction, compression, and elevation; to prevent further irritation, inflammation, and secondary infection by disinfection, protection, and rest; and to enhance healing mechanisms. Common electives include:

Cryotherapy
  Cold packs
  Cold immersions
  Ice massage
  Vapocoolant spray
Compression
  Pressure bandage
  Aircast
Protection (padding)
Elevation
Indirect therapy (reflex therapy)
Iontophoresis/phonophoresis
Auriculotherapy
Meridian therapy
Spondylotherapy
Mild pulsed ultrasound
Pulsed alternating current
Rest
  Bedrest
  Foam/padded appliance
Shoe orthotic
Immobilization
  Brace
  Rigid appliance
  Inflated appliance
  Strap
Indicated diet modification and nutritional supplementation.


2. Stage of Passive Congestion

The major goals are to control residual pain and swelling, provide rest and protection, prevent stasis, disperse coagulates and gels, enhance circulation and drainage, maintain muscle tone, and discourage adhesion formation. Common electives include:

Indirect articular therapy (reflex therapy)
Alternating superficial heat and cold
Pressure bandage
Light nonpercussion vibrotherapy
Passive exercise of adjacent joints
Mild surging alternating current
Mild pulsed ultrasound
Phonophoresis
Cryokinetics (passive exercise)
Meridian therapy
Spondylotherapy
Rest
  Bedrest
  Foam/padded appliance
  Shoe orthotic
Immobilization
  Brace
  Rigid appliance
  Inflated appliance
  Strap
Indicated diet modification and nutritional supplementation.


3. Stage of Consolidation and/or Formation of Fibrinous Coagulant

The major goals are the same as in Stage 2 plus enhancing muscle tone and involved tissue integrity and stimulating healing processes. Common electives include:

Mild articular adjustment technics
Moist superficial heat
Thermowraps
Spray-and-stretch
Cryokinetics (active exercise)
Moderate active range-of-motion exercises
Meridian therapy
Alternating traction
Sinusoidal current
Ultrasound, continuous
Vibromassage
High-volt therapy
Interferential current
Spondylotherapy
Mild transverse friction massage
Mild proprioceptive neuromuscular facilitation techniques
Rest
  Bedrest
  Foam/padded appliance
  Inflated appliance
  Shoe orthotic
  Semirigid appliance
Indicated diet modification and nutritional supplementation.


4. Stage of Fibroblastic Activity and Potential Fibrosis

At this stage, causes for pain should have been corrected, but some local tenderness likely remains. The major goals are to defeat any tendency for the formation of adhesions, taut scar tissue, and area fibrosis and to prevent atrophy. Common electives are:

Deep heat
Articular adjustment technics
Spondylotherapy
Local vigorous vibromassage
Transverse friction massage
Spray-and-stretch
Active range-of-motion exercises without weight bearing
Motorized alternating traction
Negative galvanism
Ultrasound
Sinusoidal and pulsed muscle stimulation
High-volt therapy
Interferential current
Meridian therapy
Proprioceptive neuromuscular facilitation techniques
Rest
  Bedrest
  Foam/padded appliance
  Inflated appliance
  Shoe orthotic
  Shoelift
  Semirigid appliance
Indicated diet modification and nutritional supplementation.


5. Stage of Reconditioning

Direct articular therapy for chronic fixations
Progressive remedial exercise
Passive stretching
Isometric static resistance
Isotonics with static resistance
Isotonics with varied resistance
Plyometrics
Aerobics
Indicated diet modification and nutritional supplementation.



COMMENTARY

Mechanical and Chemical Factors of Traumatic Low Back Pain

It is well to keep in mind that low-back pain experienced after trauma can be the result of local mechanical or chemical factors, visceral reflex factors, or a combination.

Characteristics of Mechanical Pain

Mild mechanical force applied to healthy tissue does not produce pain. However, abnormal mechanical deformation occurs whenever (1) abnormal stress is applied to normal tissues (eg, postural pain), (2) abnormal stress is applied to abnormal tissues (pressure on fractures), or (3) normal stress is applied to abnormal tissues (eg, contractures).

Pain from mechanical causes is usually sharp, acute, and occurs immediately. If mechanical pain does not occur until several minutes or hours after an activity, it is likely that some position or force following the accused activity is the cause of the pain rather than the activity itself.

Mechanical pain may sometimes be intermittent, appearing and disappearing, or vary in intensity according to aggravating or beneficial circumstances. It is usually intermittent because of increased and decreased mechanical deformation forces.

In cases of pain of mechanical origin, the examiner should be able to reproduce the patient's symptoms by test movements. Immutable pain from constant mechanical deformation (eg, irreducible disc rupture) is always possible but not common. The rule to remember is that pain of mechanical origin is invariably affected by movement, for better or worse.

Considerations in Adjustive Therapy

The motion that eases pain the most (reduces mechanical deformation) usually determines the plane of adjustive therapy. An exception to this would be pain produced by motion that stretches shortened tissues. This pain subsides immediately when passive stress is removed and the joint returns to its neutral position.

In either subluxation or displaced IVD substance (ie, end plate, anulus, nucleus pulposus), a dynamic adjustment should be given in the direction that decreases mechanical deformation and pain. In some instances, a dynamic adjustment will be necessary to free adhesions and locked facets. When shortened tissues are involved, slow rhythmic manipulation increasing in force should be given in the direction that stretches the contracted tissues and at the moment increase pain. Obviously, choice of technic requires careful differentiation prior to adjustment.

Characteristics of Chemical Pain

Chemical irritants accumulate in damaged tissue soon after injury. As soon as the nociceptive receptor activity is enhanced, pain is experienced. Chemical irritation can be the result of any inflammatory, infectious, traumatic, or possibly psychic-induced process of sufficient degree. It can also be the result of any abnormal metabolic by-product, especially that of ischemia, of sufficient concentration to irritate free nerve endings in involved tissues.

In contrast to pain of mechanical origin, pain from chemical causes is constant, dull, and aggravated by normal movements as long as the chemical irritants are present in sufficient concentration. Because of accumulating irritants, the pain may not occur until several minutes or hours after an injury occurred. Chemical pain subsides during the natural healing process as scar tissue forms. Rarely does chemical pain from trauma extend past 20 days postinjury.


CONTUSIONS

Low-Back Contusions

Fortunately, most injuries seen involve uncomplicated contusions and mild subluxations of the spine and adjacent free ribs that are relatively easy to manage. However, severe contusion of the lumbodorsal fascia is occasionally seen that may lead to an extensive painful hematoma. When severe injury does occur, the effect varies from sport to sport, job to job. In some cases, a silent condition such as a spina bifida occulta may be brought to light only through examination following strenuous activity.

Gluteal Contusions

This large muscle is firmly enclosed in strong fascia, especially its deep surface. Because of this, it is often involved in a compartment syndrome initiated by trauma that is misdiagnosed as sciatica when a kick to or a fall on the buttocks is in the history. Because its fascia is continuous with that of the fascia lata, differentiation must be made from tensor fascia lesions, "hip pointer," and proximal femur lesions.

Contusions, especially to the ischial tuberosity and the well-developed buttocks, are sometimes seen. Just walking may be aggravating, but the pain is usually not severe. Swelling and bleeding may be extensive, but it is reduced quickly if cold is applied immediately. Recurrent bleeding is always a problem, though its likelihood is reduced if cold is continued for 3 or 4 days. Full healing will usually take place within a month if re-injury does not occur.



MANAGEMENT OF LOW-BACK SPASM

Painful spastic muscles guarding motion in the lower spine (lumbago) can be viewed by watching body attitude (eg, stiff carriage) and by efforts to bend the spine forward, backward, to the side, and while arising from a chair. If we are familiar with the average range of motility in each direction and at different ages with different biotypes, this test is usually easy and rapid. Spinal extension is typically the least satisfactory motion.

General Approach

The empiric benefits of articular adjustments are well known. To relieve muscle spasm, heat is helpful but cold and vapocoolant sprays have sometimes shown to be more effective. The effects of traction are often dramatic but sometimes short-lived if a herniated disc is involved. It is well to note that a predisposing ankle or arch weakness may exist that requires special stabilization.

Passive Stretch

Mild passive stretch is an excellent method of reducing spasm in the long muscles, but heavy passive stretch destroys beneficial reflexes. For example, hypertonic erectors of the spine can be simply relaxed by placing the patient prone on a split headpiece adjusting table and tilting the abdominal and pelvic section upward to flex the spine. The weight of the structures above and below the midpoint of the flexed spine offer a mild stretching effect, both cephally and caudally. The muscles relax within 2--3 minutes. Thumb pressure, placed on a trigger area, is then directed toward the muscle's attachment and held for a few moments until relaxation is complete. Psoas or quadriceps spasm can be relaxed with Bragard's maneuver by holding the straight leg for a minute or more in extension while dorsiflexing the foot.

Vapocoolant Technique

The patient is placed in the lateral recumbent position with the involved side upward and the knees slightly flexed. Isolate trigger areas and site of major pain, and spray sites. At the same time, ask the patient to pull his knees toward his chest and then slowly return them to the relaxed position. Repeat the spraying and active movement three or four times. Have the patient indicate with his finger the major source of pain. As the pain shifts position, spray the affected area. Once relief is obtained, have the patient turn to the other side if the condition is bilateral, and repeat the procedure. When relief has been obtained in flexion-extension, add rotation and lateral flexion, spraying painful sites as necessary between movements. Have the patient attempt to walk, and spray the painful area if necessary. If possible, have the patient bend forward with his heels on the floor.

Once relief is obtained, correct any subluxations isolated, support the area, and instruct the patient in mild home stretching exercises for 1--2 minutes each half hour during the waking hours. Advise the patient to avoid remaining in any one position for too long. Begin resistance, stretching, and weight-bearing exercises as soon as acute symptoms subside.

Adjuncts

Other methods may prove helpful. Peripheral inhibitory afferent impulses can be generated to partially close the presynaptic gate by acupuncture (needle or electric) or transcutaneous nerve stimulation. Isotonic exercises are useful in improving circulation and inducing the stretch reflex when done supine to reduce exteroceptive influences on the central nervous system. An acid-base imbalance from muscle hypoxia and acidosis may be prevented by supplemental alkalinization. In chronic cases, relaxation training and biofeedback therapy are often beneficial.



ACUTE LUMBOSACRAL SPRAIN/STRAINS

Sprains

Low back sprains are frequent. Heavy loads or severe blows may rupture some associated ligaments and/or subluxate the joint. Pain may be local or referred. Symptoms are relieved by rest and aggravated by activity. Care must be taken to distinguish lumbar sprains from a sacroiliac or hip lesion.

  Diagnosis

Localized tenderness and various clinical tests are helpful in differentiation. In the well-conditioned individual, IVD conditions are more often, but not exclusively, attributed to extrinsic blows and intrinsic wrenches. A comprehensive history is vital to arrive at an accurate diagnosis and offer the best management and counsel. Points in differentiating lumbar nerve, root, and cord lesions are shown in Table 2.

Table 2. Dissimilarity of Nerve, Root, and Cord Lesions

Nerve Lesions	Caudal-Root Lesions	Lumbosacral Cord Lesions
Usually unilateral	Usually bilateral, but not symmetrical	Usually bilateral and symmetrical
Pain on pressure over nerve trunks is common	Not present; superficial hyperalgesia or anesthesia dolorosa	Not present
Symptoms present in nerve distribution	Symptoms in segmental distribution	Symptoms in segmental distribution
Pain often aggravated by movement, but spontaneous pain not severe	Spontaneous pain is often severe, movement of limbs not painful, coughing, sneezing are painful	Pain absent unless nerve roots are implicated
Sensory loss involves pain, touch, temperature	Same	Sensory dissociation may be present with unilateral lesions in upper lumbar segments
Reflexes lost in areas affected; others are not increased	Same	Achilles reflex may be absent and patellar increased or vice versa, or all reflexes may be lost
Seldom involve dorsal divisions of peripheral nerves	Involve both dorsal and ventral distributions	Involve both dorsal and ventral distributions
Muscle atrophy and reaction of degeneration may be present	Same	Same
Fibrillation in muscles is absent or slight	Same	Fibrillation of muscles active
Trophic sores absent	Trophic sores unusual or mild	Trophic sores common and severe
Sphincters not affected	Sphincters may be affected	Sphincters usually affected
No loss of sexual power	Often some loss of sexual power	Sexual power lost or dissociated-
Roentgenography	Film may show pathology below L1 (fracture, dislocation, caries)	Films may show some pathology in T11, T12, or L1

Horizontal shear forces seem the most damaging forces for disrupting the ligament straps between vertebrae. Because of the lax capsules, a minor sprain can produce a severe synovitis at the posterior joints. If the synovium is torn on the side of tension, severely irritating hemarthrosis results and fragments of fractured articular cartilage and periosteum may form loose bodies in the joint. The distorted articular surface may produce chronic instability from erosion and degeneration, leading to reactionary osteophytoses which in turn are subject to fracture. Repeated episodes of minor trauma and tissue changes predispose progressive degenerative arthritis.

Lumbosacral Sprain

Acute lumbosacral sprains have a high incidence. They occur commonly in the 25--50 age group, and sedentary workers are involved just as frequently as workers doing heavy labor. Heavy loads or severe blows, especially at an unguarded moment, may rupture some associated ligaments and/or subluxate a joint. The pain may be local or referred. Overt symptoms are usually relieved by rest and aggravated by activity or high heels. Fatigue is chronic regardless of adequate rest.

Segmental Kyphosis

In almost all cases of acute lumbosacral stress, the local multifidi will be stiff or mildly splinted. When this happens, Cailliet states that the vertebral motion unit will be kyphotic. This cannot be true because the multifidi are hyperextenders in the erect position that can only produce locking in lordosis. Shortened abdominals and possibly the psoas major would be the logical muscles in the lumbar area responsible for kyphotic fixation. Mechanically, anterior disc collapse or a fixed facet separation would be a more logical cause if a segmental kyphosis presents. An associated lumbar scoliosis with pain on the side of concavity points to psoas major involvement.

Strains

Acute strains are frequently superimposed on chronic strains. The associated pain may be immediate or not occur for several hours after tissues warmed by exercise begin to cool. Because of the increased lever arm operating on the lumbar segments, the incidence of injury is two times higher in taller individuals than in shorter people. Representative signs of lumbar strain, sprain, and disc protrusion are shown in Table 3.

Table 3. Typical Signs of Spinal Strain, Sprain, and Disc Protrusion

Feature	Strain	Sprain	Disc Protrusion
Initial feeling	Tearing	Snap	Lock
Onset of pain	During lifting	Unprepared joint	Minor trauma
Area of pain	Over muscle	Convex side of curve	Concave side of pain
Location of pain	Involved muscle	Lumbosacral or sacroiliac area	Segment
Most painful action	Flexion	Hyperextension	Hyperextension with torsion
Major cause of pain	Myositis	Synovitis	Root/cord irritation
Deep pressure pain	Usually bilateral, large area, in muscle	Unilateral pain, localized, usually one joint	Often bilateral, localized, usually one joint
Percussion	Little increased discomfort	Sharp local pain	Sharp pain that radiates
Position of rest	Moves frequently	Still position	Still position
Effect of rest	Stiffens area	Relieves pain	Relieves pain
Curve pattern	Antalgic, if any	Segmental distortion	Segmental distortion
Iliac position	High on pain side	High on pain side	Low on pain side

BIOMECHANICAL INSTABILITY

Primary instability of the lumbar spine is considered a common cause of low-back pain. Instability refers to a loss of soft-tissue integrity leading to diminished intersegmental control and weakness and liability to yield under normal stress to produce abnormal articular positioning (subluxation). The cause is frequently traumatic and often seen in middle-aged males. The most common level involved is at the L4--L5 interfaces (90%). Instability may be the result of rotation with or without much tilting, flexion with or without much rotation, lateral displacement (rare without fracture), lateral tilt and wedging, or extension overstress with or without spinous process impingement.

Segmental Stability

It is obvious that each spinal segment rests on the one beneath and that the interposed joint surfaces serve as the support base of the separate segments. The force of gravity acting on each segment must be individually neutralized if the body as a whole is to be in ideal gravitational balance. Thus, joint stability is partially dependent on (1) the size of the joint surfaces, (2) the height of the segmental centers of gravity above the joint surface, and (3) the horizontal distance of the common gravity line to the joint's center. In the adult lumbar spine, the interspinous and supraspinous ligaments play a minimal role in segmental stability. White/Panjabi report that these ligaments are frequently absent, degenerated, or ruptured.

Instability Characteristics

Painful attacks with severe muscle splinting, often with brief episodes of paresis and paresthesiae, are sudden in onset and frequently bilateral as opposed to the unilateral pain of a posterolateral disc protrusion. The paravertebral ligaments are extremely tender, and pain is increased by rotation. Neurologic signs and Lasegue's test are usually negative. In most cases, acute attacks of instability are quickly relieved by rest and ambulatory support.

THE ROLE OF AXIAL LIGAMENTS IN STATIC BALANCE

When standing in static equilibrium, we rest on our axial joints and ligaments. There is only light and intermittent muscle activity. As ligament support does not consume much energy, it does not contribute to fatigue. Chronic ligament tension, however, must be intermittently relieved by muscle activity and position changes to avoid chronic microtrauma.

Primary Straps

The important ligament involved in static balance is the lumbar anterior longitudinal ligament, which restricts lumbar "sinking"; the iliofemoral Y ligaments at the anterior hip, which guard hip hyperextension; the tensor fasciae latae, which assist the Y ligaments, restrict lateral sway, and help the knees to lock; and the posterior knee ligaments, which lock the knees in extension. The ankles cannot be locked, thus they require slight intermittent contraction of the leg muscles.

The Pelvic Angle

The pelvic angle appears to be the key to ligament stability. Lateral pelvic tilting from a unilateral short leg, for example, is accompanied by load shifting to the lower hip and pelvic rotation that unlocks the weight-bearing joints of the lower extremities. The lumbar spine will not bend laterally without some rotation. This change in equilibrium forces imposes increased muscle effort to maintain balance, and this leads to general fatigue.



SCIATICA

Although it is the largest nerve of the body and supplies through its branches all the muscles below the knee, the sciatic nerve is rarely injured by sudden trauma. It is often affected, however, by neuritis (sciatica), which is frequently due to intermittent trauma.

Clinical Signs

Sciatic neuralgia or neuritis is characterized by pain of variable intensity to a maximum that is almost unbearable. Pain radiates from the lumbosacral area down the thigh posteriorly and often to the sole of the foot. Muscle atrophy and the characteristic limp are usually present.

Neuropathy must be differentiated from a lumbar compression radiculopathy and vertebral canal stenosis. This is often challenging for all can be considered nerve compression syndromes. As disc herniation rarely involves several segments, neuropathy is first suspected when multiple segments are involved. When the straight-leg-raising test is made just short of pain, internal rotation of the femur increases pain and external rotation decreases pain in sciatic neuropathy but has little effect on lumbar radiculopathies.

Note the comparative height of the iliac crests. If chronic sciatic neuralgia is on the high iliac crest side, degenerative disc weakening with posterolateral protrusion should be suspected. If occurring on the side of the low iliac crest, consider the possibility of a sacroiliac slip and lumbosacral torsion as the cause.

There is a lessening or lack of the deep tendon reflex in sciatica (Babinski's sciatica sign). When the patient's great toe on the affected side is flexed, pain will often be experienced in the gluteal region (Turny's sign). Also in sciatica, the pelvis tends to maintain a horizontal position despite any induced degree of scoliosis (Vanzetti's sign), unlike other conditions in which scoliosis occurs when the pelvis is tilted.

Classic Orthopedic/Neurologic Tests

Lasegue's Classic Straight-Leg-Raising Test. The patient lies supine with legs extended. The examiner places one hand under the heel of the affected side and the other hand is placed on the knee to prevent the knee from bending. With the limb extended, the examiner flexes the thigh on the pelvis keeping the knee straight. Normally, the patient will be able to have the limb extended almost 90º without pain. If this maneuver is markedly limited by pain, the test is positive and suggests sciatica from a lumbosacral or sacroiliac lesion, subluxation syndrome, hamstring tightness, disc lesion, spondylolisthesis adhesions, or IVF occlusion. Some examiners report that pain at 30° indicates sacroiliac involvement; at 60º, lumbosacral disorder; 80º, L4--L5 problem.

A second mode of using this test is to have the patient attempt to touch the floor with the fingers while the knees are held in extension during the standing position. Under these conditions, the knee of the affected side will flex, the heel will slightly elevate, and the body will elevate somewhat to the painful side.

Studies confirm that when Lasegue's sign is positive, the pupils will dilate, blood pressure will rise, and the pulse will become rapid. These phenomena are not present in the malingerer or psychoneurotic individual.

Bragard's Test. If Lasegue's test is positive at a given point, the leg is lowered slightly and dorsiflexion of the foot is induced. The sign is negative if pain is not increased. A positive sign is a finding in sciatic neuritis, spinal cord tumors, IVD lesions, and spinal nerve irritations. A negative sign suggests muscle involvement such as tight hamstrings. Bragard's test helps to differentiate the pain of sciatic involvement from that of sacroiliac involvement as the sacroiliac articulation is not stressed by the Bragard maneuver, nor is the lumbosacral joint.

Fajersztajn's Test. When straight leg raising and dorsiflexion of the foot are performed on the asymptomatic side of a sciatic patient and this causes pain on the symptomatic side, there is a positive Fajersztajn's sign that is particularly indicative of a sciatic nerve root involvement as produced by a disc syndrome, dural root sleeve adhesions, or some other space-occupying lesion. This maneuver is sometimes called the "well" or "cross-leg" straight-leg-raising test.

Demianoff's Test. This is a variant of Lasegue's test used in lumbago and funiculitis with the intent of differentiating between lumbago and sciatica. When the affected limb is first extended and then flexed at the hip, the corresponding half of the body lowers and with it the muscle fibers fixed to the lumbosacral segments. This act, which stretches the muscles, induces sharp nonsciatic lumbar pain. Lasegue's sign is thus negative as the pain is caused by stretching the affected muscles at the posterior portion of the pelvis rather than stretching the sciatic nerve. To do the test with the patient supine, the patient's pelvis is fixed by the examiner's hand firmly placed on the ASIS, and the other hand elevates the leg on the same side. No pain results when the leg is raised to an 80º angle.

When lumbago and sciatica coexist, Demianoff's sign is negative on the affected side but positive on the opposite side unless the pelvis is fixed. The sign is also negative in bilateral sciatica with lumbago. The fixation of the pelvis prevents stretching the sciatic nerve, and any undue pain experienced is often associated with ischiotrochanteric groove adhesions. Demianoff's sign is valuable in determining local lesions of muscles, upper lumbar nerve roots, and funicular sciatica.

Belt Test. The standing male patient bends forward with the examiner holding the patient's leather belt at the back. If bending over without support is more painful than with support, it suggests a sacroiliac lesion. Conversely, if bending over with support is more painful than without support, it suggests lumbosacral or lumbar involvement.

Deyerle-May Test. This test is often helpful in differentiating the various etiologies of sciatic pain and is particularly designed to differentiate between pain from pressure on the nerve or its roots and pain due to other mechanisms in the lower back. Compression or tractional pressure on muscles, ligaments, tendons, or bursae may cause reflex pain that often mimics direct nerve irritation. Reflex pain does not usually follow the pattern of a specific nerve root, is more vague, does not cause sensory disturbances in the skin, comes and goes, but may be very intense.

Instruct the patient to sit very still and brace himself in a chair with his hands. The painful leg is passively extended until it causes pain, then lowered just below that point. The leg is then held by the examiner's knees and deep palpation is applied to the sciatic nerve high in the popliteal space that has been made taut by the maneuver. Severe tenderness indicates definite sciatic irritation or a root compression syndrome as opposed to other causes of back and leg pain such as the stretching of strained muscles and tendons or the movements of sprained articulations.

Management

Referred pain from an organic lesion is first excluded. As direct trauma to the nerve is so rare, careful evaluation of lumbar, sacral, and sacroiliac subluxation-fixations must be made, as well as lower back, pelvic, and hip muscles and trigger points. Corrective osseous adjustments, muscle techniques, and reflex techniques should be applied when indicated. Local heat and corrective muscle rehabilitation speed recovery when applied in the appropriate stage. Of all nerves in the body, the sciatic is one of the slowest to regenerate. The feet, upper cervical area, thoracolumbar junction, and overall posture should be evaluated for signs of predisposing defects in biomechanics.


THORACOLUMBAR TRIGGER POINTS

The Thoracic Area

The common trigger points of the thoracic region are the scalene, pectoralis minor, and serratus anterior. These points are often sites of secondary reaction to lumbar dysfunction.

The Lumbar Area

Common trigger points of the lumbar area are located (1) alongside the T12--L1 spinous processes and (2) alongside the L5--S1 spinous processes. The T12--L1 trigger, often associated with a T12 spinous tipped posterosuperior, frequently refers pain to the iliac crest with secondary nodules found deep along the posterosuperior aspect of the crest. The L5--S1 point is usually in the multifidi. Trigger points may also be found in the erector spinae, when the patient is prone, about an inch lateral from the spinous processes.

Management

Rest and warmth (to increase oxygen supply) are the best therapy in immediate pain following muscle overexertion. Delayed spasms are best treated by stretching to activate the Golgi tendon organs and the myotatic stretch reflex. Stretching reduces EMG activity, but it would be contraindicated during the acute stage if fresh muscle tears exist.



INTERVERTEBRAL DISC SYNDROME

It is generally agreed that a true diagnosis of disc herniation with or without fragmentation of the nucleus pulposus can only be made on surgical intervention or special imaging techniques. Thus the term "intervertebral disc syndrome" is generally used when conservative diagnostic means are used exclusively. There is considerable dog