FILM: Lateral cervical
NAME: HORIZONTAL LINE OF THE ATLAS
PROCEDURE: Draw a line through the anterior and posterior tubercles of the atlas.
NORMAL: Forms a 7-20 degree angle with the true horizontal line.
SIGNIFICANCE: Anterior-superior or anterior-inferior subluxation of the atlas.
FILM: Lateral cervical
PROCEDURE: Draw the horizontal line of the atlas and a line along the inferior margin of the body of C7.
NORMAL: 35-40 degrees.
SIGNIFICANCE: Above 45 degrees = Hyperlordosis
Below 35 degrees = Hypolordosis
FILM: Lateral cervical
PROCEDURE: Draw a line from the superior hard palate to the posterior foramen magnum.
NORMAL: Odontoid process should be below this line.
SIGNIFICANCE: If odontoid breaks the line it is a sign of basilar
invagination or platybasia.
FILM: Lateral cervical
NAME: HORIZONTAL LINE OF THE AXIS
PROCEDURE: Draw a line from the middle of the inferior surface of the body of C2 to the middle of the inferior surface of the spinous process of C2.
NORMAL: This line should be horizontal and parallel to Chamberlain's line.
SIGNIFICANCE: Subluxation of the axis.
FILM: Lateral cervical, flexion lateral and extension lateral
NAME: PHYSIOLOGICAL LINES OF STRESS
PROCEDURE: Draw a line along the posterior margin of the odontoid process.
Draw a line along the posterior margin of the body of C7.
Extend both lines until they intersect.
NORMAL: The lines should intersect between C4 and C5 on neutral and extension lateral and between C5 and C6 on the flexion lateral.
SIGNIFICANCE: Marked alterations in the point of greatest stress
and strain indicate limitation of ion from subluxation, fixation and splinting
muscle spasm due to acute cervical trauma or limitation of motion due to
advancing degenerative changes and discogenic spondylosis.
FILM: Cervical neutral lateral, flexion lateral and extension lateral
PROCEDURE: Draw a line from body-pedicle junction to body pedicle junction along the entire cervical spine.
NORMAL: The line should form a smooth curve on the neutral lateral and even stair step on the flexion and extension laterals.
SIGNIFICANCE: A break in the line indicates a sprain with subluxation.
A stair step effect on the neutral lateral indicates a strain with subluxation.
A marked interruption of the line indicates a possible fracture of the
neural ring.
FILM: Cervical flexion and extension laterals
NAME: CERVICAL RANGE OF MOTION
PROCEDURE: Draw a line tangential to the base of the occiput and the tip of the mandible.
Draw another line tangential to the posterior body of C6.
Extend both lines until the intersect.
Subtract the acute angle on the flexion view from the obtuse angle on the extension view.
NORMAL: 80-90 degrees
SIGNIFICANCE: Above 90 degrees = Hypermobility
Below 80 degrees = Hypomobility