Spine (Phila Pa 1976). 2012 (Sep 1); 37 (19): 1657-1666 ~ FULL TEXT
Mieke Dolphens; Barbara Cagnie; Pascal Coorevits; Guy Vanderstraeten; Greet Cardon; Roseline D'hooge; Lieven Danneels
Department of Rehabilitation Sciences and Physiotherapy,
Faculty of Medicine and Health Sciences,
Ghent University, Artevelde University College, Ghent, Belgium
STUDY DESIGN: Cross-sectional baseline data set on the sagittal standing posture of 1196 adolescents.
OBJECTIVE: To describe and quantify common variations in the sagittal standing alignment in boys and girls who are in the same phase of growth and to explore the association between habitual standing posture and measures for spinal pain.
SUMMARY OF BACKGROUND DATA: Data on postural characteristics and spinal pain measures in adolescence are sparse, especially when somatic and biological maturity status is to be considered. Our understanding of the relationship between standing posture in the sagittal plane and spinal pain is also deficient.
METHODS: A total of 639 boys (age [mean ± SD], 12.6 ± 0.54 yr) and 557 girls (10.6 ± 0.47 yr), with predicted years from peak height velocity (PHV) being 1.2 ± 0.71 and 1.2 ± 0.59 pre-PHV, respectively, were studied. Postural examination included the assessment of global alignment and local spinopelvic characteristics, using post hoc analyses of digital images and direct body measurements (palpation, digital inclinometry, and wheeled accelerometry). Spinal pain experience was assessed by questionnaire.
RESULTS: A wide interindividual variation in sagittal posture characteristics was observed. Logistic regression analyses yielded global alignment parameters to be associated with low back pain (lifetime prevalence), neck pain (lifetime prevalence, 1–mo prevalence, and doctor visit), and thoracic spine pain (doctor visit) outcome measures. None of the included local spinopelvic parameters could be identified as an associated factor with measures of spinal pain.
CONCLUSION: The orientation of gross body segments with respect to the gravity line seems superior to local spinopelvic features in terms of clinical importance, at least in the current pre-PHV cohort. Opportunities may exist for postural subgrouping strategies to begin with global alignment parameters in order to gain further insight into the relationship between sagittal alignment and the relative risk of developing spinal pain/seeking medical consultation for this pain.
From the FULL TEXT Article:
There is a belief among clinicians that “nonneutral”
postures when compared with “neutral” or
“ideal” postures involve different patterns of mechanical
loading and motor control, resulting in a mechanism with
tissue strain and pain. Consequently, postural retraining has
traditionally been an integral part of physiotherapeutic intervention
in the prevention and treatment of spinal pain disorders.
Evidence from epidemiological studies, however, does
not support an association between sagittal spinal curves and
spinal pain. [1, 2] It is also well established that the physiological
upright standing posture can be reached in a different way
for each person with a unique and individual pattern of spinopelvic
balance and sagittal alignment. [3, 4] Accordingly, previous
publications have documented a high degree of variability
in the sagittal standing alignment of the human spine and
pelvis in healthy adolescents, [5–7] adults, [3, 5 ,8 ,9] middle-aged and
older subjects, 10 and populations experiencing spinal pain. [11–13]
Characteristic changes in sagittal alignment have also been
identified throughout the entire time of ontogenesis. [5, 14–18]
Two separate yet intermingled control mechanisms are
involved in building up standing posture: one relating to the
control of the center of mass projection with respect to the
feet, and another relating to the orientation of body segments
with respect to the vertical.  The center of gravity projection
or the gravity line has been shown to be located within a narrow
perimeter in relation to the feet in standing subjects. [18, 20]
On the contrary, when regarding the geometry of the body,
one viewpoint in the literature is that posture is based on
the superimposed segments (head, trunk, and legs), each of
which is linked to the next, preserving the specifi c orientation
of each segment with respect to the external world and/
or adjacent segment.  Only a relatively few studies regarding
posture or its clinical relevance have addressed the orientation
of gross body segments in space by implementing a type of
a sagittal plumb line assessment, [16, 21–27] whereas a multitude
of studies have focused on regional or segmental spinopelvic
features. [10, 11, 14, 28–30] It should be noted that most of the studies
that have considered global alignment were radiological
examinations, implying that an accurate representation of
the relaxed standing posture might be challenged.  Furthermore,
anatomically remote factors, such as the alignment of
the lower limb segment, have been largely overlooked despite
their potential signifi cance in closed kinematic chain activities
such as standing. 
In a recent systematic overview of the research literature
on the epidemiology of adolescent spinal pain,  it was concluded
that idiopathic adolescent spinal pain (IASP) is a significant public health issue, with prevalence figures increasing
with age in the adolescent period and approaching those in
adults by around 18 years of age. As IASP may result in a
risk factor for spinal pain as in adult,  the focus in relation to
research, prevention, and treatment may be predominantly on
the young population. Researching individuals in puberty is
a challenge because puberty is accompanied by major physical
growth and substantial brain maturational changes. 
Although so-called “growing pains” are reported to be common
in younger adolescents  and back pain might be considered
a “normal life experience” for many young people, 
the fact that the early adolescent increase in back pain is
associated with pubertal status is striking. [37–41] Accordingly,
a potential infl uence of puberty on pain, pain perception, or
both has been postulated.  Furthermore, it has been argued
that spinal deformities can easily develop during adolescence,
with the development and progression of these deformities
can be explained in biological and mechanical terms. [42, 43] Adolescent
idiopathic scoliosis, for instance, is shown to be linked
to peak growth velocity during puberty  and late pubarche,  and other conditions, for example, Scheuermann disease,
seem to have a peak around puberty. 
Although the potential influence of puberty-directed mechanisms
on both posture and IASP seems well recognized, maturity
status has rarely been applied in research on aforementioned
issues or their interrelation. It is well known that girls,
on average, mature 2 years before boys. 46 Therefore, the aims
of this study were
(1) to document normal variations in the sagittal
standing alignment including gross body segment indexes
and spinopelvic characteristics and
(2) to explore the association
between habitual standing posture and measures for spinal
pain within a representative sample of young adolescents in
Flanders (Belgium), taking into account their maturity status.
MATERIALS AND METHODS
A total of 639 boys of mean age 12.6 ± 0.54 years (range, 11.4–
15.0 yr) and 557 girls of mean age 10.6 ± 0.47 years (range,
9.6–13.0 yr) participated in this study. All boys were first-grade
students of mainstream secondary education in the Flemish
Community of Belgium, whereas girls were all fifth graders
of primary education. Schools were selected to obtain a representative
sample of youth in Flanders regarding educational
networks and educational levels. Subjects were excluded if they
had a history of neurological conditions, rheumatic disorders,
metabolic or endocrine diseases, major congenital anomalies,
skeletal disorders (major leg length discrepancy, spondylolysis,
spondylolisthesis, major scoliosis), connective tissue disorders,
previous spinal fracture, or previous spinal surgery.
All children and guardians provided written informed consent,
and ethical approval was granted by the ethics committee
of the Ghent University Hospital.
Testing included sagittal plane posture assessment during
habitual standing, anthropometric measurements, and
completion of self-report spinal pain measures. As part of a
larger study, an extended selection of physical characteristics,
lifestyle factors, and medical issues were recorded, as were
sociodemographic, psychological, and psychosocial factors.
However, this is beyond the scope of this study. Evaluation
occurred during a 6–month period from September 2008 to
February 2009 and was organized at schools and local pupil
Experimental Protocol—Habitual Posture
To quantify global alignment characteristics and local spinopelvic
features, post hoc analysis of digital images and a
clinical screening protocol (consisting of direct palpation,
inclinometry, and wheeled accelerometry) were used, respectively
(see Angular Measures Describing Global Sagittal
Alignment and Spinopelvic Sagittal Alignment Parameters).
Retroreflective markers were first placed on the C7 spinous
process, the apex of the thoracic kyphosis, the infl ection point
where the spine transitions from kyphosis to lordosis, the
apex of the lumbar lordosis, the L5 spinous process, the left
greater trochanter, left lateral malleolus, left anterior superior
iliac spine (ASIS), and left posterior superior iliac spine (PSIS)
by 1 trained examiner. Participants were instructed to stand
in their normal, comfortable, relaxed posture, arms resting by
the sides, with feet shoulder-width apart and equally balanced
on both feet. To standardize the head posture, participants
viewed a visual target set 1.5 m in front of them at eye level.
Postural data were obtained at the end from 3 standing trials,
with each trial lasting 30 seconds. Participants were asked to
walk between trials for several steps.
Angular Measures Describing Global Sagittal Alignment
For the assessment of global alignment characteristics, 4 angular
measures were determined from photographs of the left
lateral view obtained by a 12.40–megapixel digital camera
(EOS 450D digital camera; Canon, Lake Success, NY), using
a standardized photographic setup. Specifi cally, parameters
were calculated from the third lateral digitized photograph
of the subjects with retrorefl ective markers placed on bony
landmarks, using ImageJ software (National Institutes of
Health, Bethesda, MD) as follows (Figure 1):
Pelvic displacement angle: Angle between the line joining
the greater trochanter and the lateral malleolus and the
vertical through the former. A positive value represents a
forward carriage of the pelvis relative to the base of support
as measured at the ankle, whereas a negative value
indicates a backward carriage of the pelvis.
Trunk lean angle: Angle sustained by the line joining the
greater trochanter and spinous process C7 with respect
to the vertical through the latter. By convention, this
angle is expressed as a positive value if the spinous process
C7 is posterior to the greater trochanter (backward
inclination of the trunk) and negative if it is anterior to
the greater trochanter (forward inclination of the trunk).
Body lean angle: Angle between the line joining the lateral
malleolus and the spinous process C7 and the vertical
through the latter. A positive value indicates the vertical
projection of the C7 spinous process to be posterior to
the lateral malleolus; a negative value indicates this projection
to be anterior to the lateral malleolus.
Craniovertebral angle: Angle formed by the horizontal
drawn through the C7 spinous process and the line
joining the C7 spinous process with the tragus of the
ear. The smaller this angle, the greater the forward head
Spinopelvic Sagittal Alignment Parameters
Six lumbopelvic and 3 thoracic parameters were assessed.
In this study, the “lumbar” segment of the spine was
located between the inflection point where the spine transitions
from lordosis to kyphosis and the L5–S1 interspace.
Similarly, the “thoracic” segment was defined as existing
between the C7–T1 interspace and the inflection point.
The determination of lordotic and kyphotic segments was
independent of the anatomic location of the thoracolumbar
junction at T12–L1.
Lumbopelvic features: Lumbar characteristics that were
assessed included the number of vertebrae in the lumbar lordosis,
the vertebral level of the lumbar apex, and the total
degrees of included curvature. The first 2 parameters were
determined by 1 trained examiner via visual inspection and
palpation; the degree of lumbar lordosis was calculated using
the sum of segmental angles of appropriate vertebral sections
obtained by a skin-surface electromechanical device, the Spinal
Mouse (Idiag; Voletswil, Switzerland). The intratester and
intertester and day-to-day reliability of this wheeled accelerometer
has been published in previous studies. [47–49]
To describe the pelvic orientation in the sagittal plane,
2 angular pelvic measures were assessed: pelvic tilt and sacral
inclination. Pelvic tilt was quantified via the ASIS-PSIS angle
(i.e. , the angle between the horizontal and the line connecting
the ASIS and the PSIS), using the Pro 3600 digital inclinometer
(SPI-Tronic; Penn Tool Co, Maplewood, NJ) mounted on
a caliper with an accuracy of 0.1°. In this study, the left side
of the subjects was used for measurement. By convention, the
pelvic tilt angle is expressed as a positive value if the ASIS is
inferior to the PSIS and as a negative value if it is superior to
the PSIS. The sacral inclination with respect to the vertical
was measured using the Spinal Mouse device, with positive
values indicating a forward inclination of the sacrum and negative
values representing backward inclination. In addition,
the vertebral level of the intercristal line was determined as a
measure of pelvic height. This was done via palpation.
Thoracic spine parameters: The geometric thoracic features
that were assessed included the vertebral level of the inflection
point where the spine transitions from kyphosis to lordosis,
the apex of the thoracic curve, and the degree of included
kyphosis. The first 2 parameters were determined via visual
inspection and palpation; the degree of thoracic kyphosis was
calculated as the sum of segmental angles of appropriate vertebral
sections obtained by the Spinal Mouse.
Four anthropometric variables (chronological age, stature,
sitting height, and body mass) were measured along the
guidelines recommended by the Saskatchewan Childhood
Growth and Development research group (written personal
communication, Prof Mirwald) and were used in sex-specific
regression equations to predict age from peak height velocity
(PHV), a maturity offset. By using this method, age from PHV
maturity offset can be estimated within an error of ± 1 year
95% of the time. 
Questionnaire on Spinal Complaints
Participants completed a survey for the assessment of low
back pain (LBP).  LBP was defi ned as follows:
A discomfort or pain in the back that is considered to be
a local, uncomfortable feeling in the lumbar or lumbosacral
part of the back, with the possibility of radiation to
other parts of the body. Problems due to fatigue related
to a single exercise are not considered as back problems.
The discomfort or pain can be intermittent or constant,
gradually developed or with a sudden onset. Back pain
due to menstruation is not taken into account.
The defi nition as such was not presented to the adolescents,
but it was orally “translated” in a language that
could be understood by the adolescents. This was done during
the instructions before completion. During completion,
an examiner blinded to the results of spinal measurements
was present to provide assistance if needed. The questions
relevant to this study included the following: “Have you
ever had LBP?” “Has your low back been painful in the last
4 weeks?” “Have you ever visited a doctor for low back
complaints?” (“yes” or “no”). Analogue questions on lifetime
prevalence, 1–month prevalence, and concomitant doctor
visitation were inquired regarding neck pain (NP) and
thoracic spine pain (TSP).
The data were analyzed using PASW Statistics version 18.0
(SPSS Inc., Chicago, IL). Analyses were conducted in 3 steps
and were performed separately for boys and girls.
First, intertrial reliability of measures obtained by Spinal
Mouse (thoracic kyphosis, lumbar lordosis, and sacral inclination)
and digital inclinometer (pelvic tilt) was evaluated
using intraclass correlation coeffi cient (ICC [2,1]) for absolute
agreement  and standard error of measurements (SEM). 
The minimum difference (MD) to be considered “real” was
also calculated (MD = SEM × 1.96 × √2).  Second, standard
descriptive statistical analyses were performed on sagittal
postural characteristics and spinal pain variables; independent
samples t test was performed, with sex as a grouping
variable. Third and finally, the relationship between postural
measures and spinal pain variables was analyzed with logistic
regression. In logistic regression, univariate analysis was first
performed and combined with the indications of previously
published studies to identify the postural covariates for multivariate
analyses regardless of the P values. Variables were used
in binary logistic regression with forward likelihood ratio test
to screen the variables and to identify associated factors. All P
values were 2–sided, and P < 0.05 was considered significant.
Description of the Study Sample
The response rate was 82.4% for boys and 85.6% for girls.
Samples were representative for youth in Flanders regarding
educational networks and levels. Predicted years from
PHV, a maturational benchmark, were 1.2 ± 0.71 and 1.2 ±
0.59 years pre-PHV in boys and girls, respectively. A total of
93.6% of the boys and 96.2% of the girls were classifi ed as
pre-PHV. The average predicted age of boys and girls at PHV
was 13.8 ± 0.53 and 11.8 ± 0.44 years, respectively.
Reliability of the Field Measurements
Reliability for measures obtained by Spinal Mouse and digital
inclinometer is presented in Table 1. In general, 5 of 8 ICC
values were in the excellent range (ICC ≥ 0.75). The other 3
ICC values were in the higher portion of the good range (0.5
< ICC < 0.75). 52 The SEM (% of mean) ranged from 3.66%
Sagittal Standing Alignment
Table 2 provides descriptive data on the variation in the sagittal
standing alignment in young adolescents. As can be seen,
significant variations were present in parameters describing
global and spinopelvic postural alignment. Regarding the
lumbopelvic characteristics, for instance, the average values
for the degree of lumbar lordosis were 28.9° in boys and
30.7° in girls, with a range of 7.7° to 48.7° and 10.0° to
55.7° , respectively. The number of vertebrae in lordosis was,
on average, approaching 5, with a range from 1.5 to 8.5 both
in boys and in girls, implying the inflection point where the
spine transitioned from kyphosis to lordosis was, on average,
somewhat below the T12 level, near the anatomic location
of the thoracolumbar junction. However, this transition was
noted to occur as proximally as the T8–T9 interspace and
as distally as the L3–L4 interspace. The apex of lumbar lordosis
was located, on average, just above the L3 level, with
a range from the T12–L1 interspace (boys) and T12 level
(girls) proximally to the L5 level distally. Pelvic tilt averaged
12.3° (boys) and 13.2° (girls), with a range from –1.6° to
25.5° and –1.5° to 26.0° , respectively. The sacral inclination
angle , defined as the angle between the dorsum of the sacrum
and the vertical axis as measured externally, averaged 17.7°
forward inclination in boys and 19.7° in girls, with a range
from 4.7° (boys) or 2.3° (girls) backward inclination to 35.7°
(boys) or 40.3° (girls) forward inclination. The height of the
iliac crests was located near the L3 level, on average. This
measure of pelvic morphology, however, was noted to occur
as proximally as the L1 level and as distally as the L5 level.
The results of the independent samples t test showed significant sex differences for all mean pre-PHV postural parameters
except for the craniovertebral angle, indicating a similar
forward incline of the neck-head segment relative to the horizontal
in both sexes. Boys were found to have a significantly
bigger pelvic displacement angle ( i.e. , more forward translation
of the pelvis over the base of support as measured at the
ankle) ( P = 0.017), a smaller trunk lean angle (i.e. , less posterior
tilt of the trunk with respect to the vertical) (P = 0.003),
and a smaller body lean angle ( i.e. , more anterior body lean)
(P < 0.001) than girls. Regarding lumbopelvic features, the
mean overall lumbar lordosis was smaller in boys than in
girls (P < 0.001), boys had less vertebrae included in lordotic
curve (P = 0.002), their lumbar apex and iliac crests were
situated at a lower vertebral level (both P < 0.001), and less
anterior pelvic tilt and less forward inclination of the sacrum
(both P < 0.001) were noted. Furthermore, the mean overall
thoracic kyphosis was more pronounced in boys than in girls
(P < 0.001), with boys having more vertebral units included
in the kyphotic curve (P = 0.002) and a thoracic apex being
at a lower vertebral level (P < 0.001) than girls.
Spinal Pain Prevalence and Doctor Visit Rates for Spinal Pain
In boys, the lifetime prevalence of LBP was 28.5%. A total
of 13.8% of boys reported LBP in the month preceding
completion of the questionnaire, whereas 3.3% had ever consulted
a doctor because of LBP. In girls, prevalence on LBP
parameters amounted to 24.0%, 9.6%, and 5.4% for lifetime
prevalence, 1–month prevalence, and doctor visit, respectively.
With regard to NP, lifetime and 1–month prevalence
were 25.0% and 8.9%, respectively, in boys. About 3.3%
of all boys visited a doctor because of NP. In girls, 30.2%
and 10.1% complained of NP ever and in the past month,
respectively, and 3.4% of girls had ever visited a doctor for
Among the boys, 10.5% mentioned to have ever experienced
TSP, whereas the 1–month prevalence accounted 5.0%.
A total of 1.7% of boys had ever visited a doctor for their
TSP. In girls, these prevalence rates for TSP variables were
11.7%, 4.9%, and 2.9%, respectively.
Associations Between Sagittal Postural Parameters and Spinal Pain Measures
The dependent variables were lifetime prevalence LBP,
1–month prevalence LBP, and doctor visit because of LBP, successively.
The candidate covariates included the 4 global sagittal
alignment parameters and the 6 lumbopelvic variables. All
these were continuous variables.
In boys, among the 10 postural parameters screened by
multivariate analysis, pelvic displacement angle (odds ratio
[OR] = 1.074; 95% confidence interval [CI]: 1.008–1.144;
P = 0.027) remained in the model using binary logistic
regression, with forward likelihood ratio test regarding lifetime
prevalence of LBP. An increase in 1° pelvic displacement
has a 7.4% increase in odds of ever having experienced LBP
Results of multivariate logistic regression, however, yielded
this parameter to account for only 1.1% of the variability in
lifetime prevalence of LBP in boys (Nagelkerke R 2 = 0.011).
Regarding 1–month prevalence and doctor visit for LBP none
of the postural variables remained in the model. In girls, none
of the variables remained in the model for none of the LBP
The candidate covariates for the dependent variable (lifetime
prevalence, 1–month prevalence, and doctor visit for NP, successively)
included the 4 global sagittal alignment parameters.
In boys, 2 variables stayed in the model when considering
lifetime prevalence of NP: the craniovertebral angle (OR =
0.954; 95% CI: 0.924–0.985; P = 0.004) and the trunk lean
angle (OR = 1.077; 95% CI: 1.007–1.152; P = 0.031). Less
anteroposition of the head was associated with an approximately
5% decrease in odds of lifetime prevalence of NP,
whereas an increase in posterior trunk tilt was associated
with significantly higher lifetime odds of NP.
Results of multivariate
logistic regression yielded the model to account for
3.2% of the variability in lifetime prevalence of NP in boys
(Nagelkerke R 2 = 0.032). Regarding NP month prevalence in
boys, the only variable to stay was the trunk lean angle (OR =
1.233; 95% CI: 1.110–1.369; P < 0.001). Here, an increase
in 1° trunk lean angle had a 23.3% increase in odds of having
experienced NP in the past 4 weeks in target boys, explaining
5.8% of the variability in NP outcome (Nagelkerke R 2
= 0.058). None of the variables was significantly related to
doctor visit rate for NP.
In girls, the craniovertebral angle stayed in the model when
considering lifetime prevalence of doctor visit for NP (OR =
0.905; 95% CI: 0.824–0.994; P = 0.037). A 1° increase in
craniovertebral angle (i.e. , less forward held head) has a 9.5%
decrease in odds of having sought medical help for NP. Analyses
yielded this parameter to account for 3.5% of the variability
in doctor visit rate for NP (Nagelkerke R 2 = 0.035).
No associations were found between posture and the other
The candidate covariates for the dependent variable (lifetime
prevalence, 1–month prevalence, and doctor visit for TSP, successively)
included the 4 global sagittal alignment parameters
and the 3 thoracic parameters. The only significant association
between posture and TSP measures was found with respect to
doctor visit for TSP in boys, with the trunk lean angle staying
in the model (OR = 1.290; 95% CI: 1.041–1.598; P =
0.020): an increase in 1° in trunk lean (i.e. , more backward
reclination of the trunk) has a 29.0% increase in odds of having
visited a doctor for TSP, with this parameter explaining
5.3% of the variability in doctor visit rate for TSP.
This study yields physiological standards for several indicators
of alignment, both global and spinopelvic, measured
in a representative cohort of young adolescents in Flanders
(Belgium), using a screening protocol with clinical applicability.
A key aspect of the study design was the recruitment
of subjects according to a common maturational landmark,
the age of attainment of peak height velocity (PHV), yielding a developmental age
baseline as opposed to a chronological baseline. To the best
of the authors’ knowledge, no epidemiological studies have
been reported on sagittal full-body posture — including global
and local postural characteristics — in the growing individual,
factoring in maturity status. As shown in previous research, 
age from PHV can be predicted with a reasonable degree of
accuracy from a 1–time measurement of basic anthropometric
variables, using sex-specific multiple regression equations taking
into consideration the differential timing of the adolescent
spurt in body dimensions and their interactions with chronological
age. Predicted age at PHV within our sample (13.8
years among boys and 11.8 years among girls) was similar to
previous reported values from North American and European
The pre-PHV baseline data of this study demonstrate
the sagittal body profi le to be highly variable already in a
standardized standing position, in young adolescence. For
example, in our cohort, the vertebral level where the spine
transitions from kyphosis to lordosis was, on average, somewhat
below the T12 level, near the anatomic location of the
thoracolumbar junction. This transition was noted to occur
as proximally as the T8–T9 interspace and as distally as the
L3–L4 interspace, implying that the number of kyphotic and
lordotic vertebral units can vary significantly. A comparable
wide variation in the length of the spinal kyphotic and lordotic
segments has been noted in a normal, young adult population [6, 8 ,55] but has not yet been reported within a pre-PHV
pediatric population. Accordingly, in this study, thoracic and
lumbar curvatures of the spine were defi ned independent of
the anatomic location of the thoracolumbar junction at T12–L1, allowing for a better evaluation of the full magnitude of
the sagittal curves of the spine.
In this study, the standing human body posture was represented
by a series of 3 solid links representing 3 major
body segments (lower limbs, trunk, and head) and several
local shape indices within the spinopelvic axis. The postural
parameters we have proposed (i.e. , 4 “global” alignment
parameters: pelvic displacement, trunk lean, body lean, and
craniovertebral angle, and 9 “local” spinopelvic features:
total degrees of lumbar lordosis and thoracic kyphosis,
the number of vertebras in lordosis and kyphosis, the vertebral
level of the lumbar and thoracic apices, pelvic tilt,
sacral inclination, and pelvic height) were based on a critical
literature review and clinical insights and were intended
to identify certain morphologic features that may have an
association with the pathogenesis of spinal pain. According
to our fi ndings, none of the included “local” spinopelvic
parameters could be identifi ed as an associated factor
with any measure of spinal pain (i.e. , lifetime and 1–month
prevalence of LBP, NP, or TSP, and concomitant doctor visit
rates). Instead, results suggest global alignment parameters
to be associated with LBP (lifetime prevalence), NP (lifetime
prevalence, 1–month prevalence, and doctor visit for NP),
and TSP measures (visiting a doctor for TSP). Therefore, it
can be suggested that the orientation of various body segments
with respect to the gravity plumb line ( i.e. , anteroposterior
translations of the head, trunk, and pelvis) may be
paramount compared with the local spinopelvic characteristics
with respect to the development of symptomatic IASP
and concomitant medical care seeking, at least in pre-PHV
boys and girls. The associations between posture parameters
and spinal pain measures found in this cross-sectional data
set; however, it cannot be said to be causal, because spinal
pain itself may alter posture.
On the basis of the current data set, it is diffi cult to determine
whether the statistical sex differences for all postural
parameters, except for the craniovertebral angle, are also of
clinical relevance. The patterns of sexual dimorphism seem
to be in line with previous reports. [3, 17, 21, 26, 56] Nonetheless, caution
is required in comparing study results, given the particular
profi le of this study sample with regard to biological/
chronological age. In any case, the fi nding that the association
pattern between sagittal posture and spinal pain seems
strongly sex-specific in boys and girls within the same phase
of growth was somewhat surprising. In girls, only one association
was found between a spinal pain–related outcome
variable (having sought medical help for NP) and the candidate
postural predictors (forward held head). In boys, on
the contrary, associations were found with regard to higher
odds of lifetime prevalence LBP (forward translation of the
pelvis over the base of support, as measured at the ankle),
lifetime prevalence NP (anteroposition of the head and backward
reclination of the trunk with respect to the vertical),
1–month prevalence NP (backward reclination trunk), and
doctor visit because of TSP (backward reclination trunk).
The reason for this discrepancy between sexes is unclear, yet
possible mechanisms might include the difference in chronological
age between boys and girls or, purely hypothetical,
sex-related differences in the domination of contributing factors
within the widely accepted multifactorial nature of the
risk for children’s and adolescents’ experience of spinal pain
symptoms. [57–61] Interestingly, in a recent study conducted in
766 adolescents aged 13.0 to 15.1 years not controlling for
maturity status, there was also some suggestion that sex may
infl uence the association between postural types and back
pain measures. 
We think that part of the reason for the limited and conflicting evidence linking spinal pain to posture may be that
emphasis in research on habitual posture has been predominantly
on “local” postural characteristics whereas studies
on the overall postural presentation are rather sparse.
Within this context, arm position should be considered
attentively to obtain postural data that are representative
for the alignment in the relaxed standing position. Furthermore,
sex and somatic maturity have rarely been taken into
A potential limitation of this study is the use of postural
measures external to the body: global posture was assessed
by post hoc analysis of digital images, and local parameters
were assessed using direct body measurements (palpation,
digital inclinometry, and Spinal Mouse). The assessment protocol
used can be substantiated by its applicability in both
large-scale population studies and evidence-based practice. [26, 47–49, 62, 63] The use of palpation in general,  and the determination
of the vertebral levels of thoracic and lumbar apices
and the transition between kyphosis and lordosis via visual
evaluation and palpation in particular, may come under criticism, [65–67] the more so because a “level of ambiguity”  may
occur when 2 or more vertebrae have a similar orientation.
However, palpation and marker placement on the entire study
sample were performed by 1 single researcher with clinical
experience who used judgment and experience to select the
Another potential limitation is that the vertebral level where
the cervical lordosis transitions into a thoracic kyphosis was
not noted. Instead, the anatomic location of the cervicothoracic
transition was used in all subjects. The authors of this
study are aware that interindividual variations in transition
from the cervical to thoracic curves may exist, yet the implementation
of a variable cervicothoracic transition would have
interfered with the use of the Spinal Mouse, as this device
applies a recursive algorithm on the data obtained between a
fixed starting and end point (C7 spinous process and top of
anal crease, respectively).
A third and last potential limitation is that the postural
measures account only for small percentages of the variability
in spinal pain outcome measures despite significant associations
are shown. We speculate that there may be opportunities
for postural subgrouping strategies to begin with global
alignment parameters, as it may be that it is the interaction
between segments that is of importance.
We have completed this study to establish an initial pre-PHV cross-sectional data set describing sagittal alignment and
its association with spinal pain measures in healthy, young
adolescents. An attempt will be made to prospectively follow
these subjects in a longitudinal fashion. significant work is
now directed at developing a classification system of habitual
standing posture in the sagittal plane.
Although the potential infl uence of puberty-directed
mechanisms on both posture and IASP seems well
recognized, maturity status has rarely been applied in
research on aforementioned issues or their interrelation.
Using a screening protocol with clinical applicability,
this study yields physiological standards for several
indicators of both “global” alignment and “local”
spinopelvic features, measured in a representative
cohort of adolescents in Flanders (Belgium) before
age of attainment of PHV, a maturation benchmark.
This pre-PHV baseline data set demonstrates a wide
interindividual variation in sagittal body profi le in
Results suggest the orientation of gross body segments
to the gravity line to be superior in terms of
clinical importance; the association patterns, however,
seem strongly sex-specific.
There may be opportunities for postural subgrouping
strategies to begin with global alignment parameters
to gain further insight in the relationship between
sagittal alignment and the relative risk of developing
spinal pain/seeking medical consultation for this pain.
The authors are grateful to Gizem Irem Güvendik and Tom
Barbe for the generous assistance with data collection and
to all of the school teams, local pupil guidance centers, and
participants for their cooperation in this study.
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