Posterior Basicranium Asymmetry and Idiopathic Scoliosis
ABSTRACT Study design Are there neuro-anatomical abnormalities associated with idiopathic scoliosis (IS)? Posterior Basicranium (PBA) reflects cerebellum growth and contains vestibular organs, two structures suspected to be involved in scoliosis. Objective The aim of this study was to compare posterior basicranium asymmetry (PBA) in Idiopathic scoliosis (IS) and normal subjects. Method: To measure the shape of PBA in 3D, we defined an intra-cranial frame of reference based on CNS and guided by embryology of the neural tube. Measurements concerned three directions of space referred to a specific intra cranial referential. Data acquisition was performed with T2 MRI (G.E. Excite 1.5T, mode Fiesta). We explored a scoliosis group of 76 women and 20 men with a mean age of 17, 2 and a control group of 26 women and 16 men, with a mean age of 27, 7. Results: IS revealed a significant asymmetry of PBA (Pr>|t|<.0001) in 3 directions of space compared to the control group. This asymmetry was more pronounced in antero-posterior (AP) and lateral direction, forming a torque of the posterior base shape associated with identical cerebellar torque. Comment: texte 17 pages, 8 figures, 1 table Corrected Title
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ABSTRACT: Induction of the otic placode, which gives rise to all tissues comprising the inner ear, is a fundamental aspect of vertebrate development. A number of studies indicate that fibroblast growth factor (Fgf), especially Fgf3, is necessary and sufficient for otic induction. However, an alternative model proposes that Fgf must cooperate with Wnt8 to induce otic differentiation. Using a genetic approach in zebrafish, we tested the roles of Fgf3, Fgf8 and Wnt8. We demonstrate that localized misexpression of either Fgf3 or Fgf8 is sufficient to induce ectopic otic placodes and vesicles, even in embryos lacking Wnt8. Wnt8 is expressed in the hindbrain around the time of otic induction, but loss of Wnt8 merely delays expression of preotic markers and otic vesicles form eventually. The delay in otic induction correlates closely with delayed expression of fgf3 and fgf8 in the hindbrain. Localized misexpression of Wnt8 is insufficient to induce ectopic otic tissue. By contrast, global misexpression of Wnt8 causes development of supernumerary placodes/vesicles, but this reflects posteriorization of the neural plate and consequent expansion of the hindbrain expression domains of Fgf3 and Fgf8. Embryos that misexpress Wnt8 globally but are depleted for Fgf3 and Fgf8 produce no otic tissue. Finally, cells in the preotic ectoderm express Fgf (but not Wnt) reporter genes. Thus, preotic cells respond directly to Fgf but not Wnt8. We propose that Wnt8 serves to regulate timely expression of Fgf3 and Fgf8 in the hindbrain, and that Fgf from the hindbrain then acts directly on preplacodal cells to induce otic differentiation.Development 03/2004; 131(4):923-31. · 6.21 Impact Factor
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ABSTRACT: The etiology of idiopathic scoliosis is still unsolved, despite extensive research. This paper analyzes the different factors of relevance. Recent investigations have convincingly demonstrated the hereditary traits of idiopathic scoliosis. In the adolescent group a specific growth pattern has also been demonstrated, while muscular factors and biochemical changes of connective tissues are somewhat more uncertain. A significant number of patients demonstrate asymmetries in the vestibular apparatus and electroencephalographic abnormalities. Because of the essential role of the vestibular and central nervous systems in the postural equilibrium, functional asymmetries or minor pathologic changes in these structures might also be factors of importance. It is our view that adolescent idiopathic scoliosis should be regarded as a multifactorial disease. Combining the findings in recent investigations, a possible model for the pathogenesis of the disease is outlined. (C) Lippincott-Raven Publishers.Spine 08/1977; 2(3). · 2.16 Impact Factor
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ABSTRACT: Electromyographic (EMG) responses of erector spinae to a postural perturbation have been described and interpreted as an unloading reflex. Moreover, these responses have been found clearly and constantly abnormal in subjects presenting a progressive idiopathic scoliosis when compared with responses observed in subjects presenting a nonprogressive scoliosis or in normal subjects. To investigate responses to obtain more precise information on their components, on their origin, and on their variations in scoliotic children. Thirteen scoliotic children, with 3 cases of fast progressive idiopathic scoliosis, as well as 3 healthy subjects. The study was carried out at the Swiss Institute of Chiropractic in Bern Switzerland. The subjects were standing on a specially constructed platform that could be suddenly tilted either to the right or to the left. Thoracic and lumbar paraspinal muscle activity was recorded with pairs of self-adhesive surface bipolar EMG electrodes. The responses were analyzed to detect components and study their time course and relative amplitude in successive trials; characteristics common to different subjects were looked for. The presence of short-latency responses and later activities following a postural perturbation was confirmed. In a given subject, these components vary in amplitude and time course from one trial to another. On the other hand, the differences found across subjects are not significantly different from those found within the various subjects. Our results exhibit some differences with previous data. They lead to a different neurophysiological interpretation and they indicate that the stimulus and the responses need more precise analysis before being used as a diagnostic and prognostic tool in evolutive scoliosis.Journal of manipulative and physiological therapeutics 01/2004; 27(6):375-80. · 1.06 Impact Factor
Title : Posterior Basicranium asymmetry and idiopathic scoliosis
Authors :D. L. Rousie, Docteur en Neurosciences (1), O. Joly, PhD student (1), A. Berthoz,
Professeur au College de France (1), ( (1) Laboratoire de la perception et de l action, College
de France, Paris)
Name and adress for correspondence : Docteur Rousie, 3 rue Saint Louis, 59113 Seclin
France. Fax: 0033 320 32 35 44, Tel. 0033 320 90 12 29, email@example.com
Fondation Yves Cotrel pour la recherche en pathologie rachidienne. Institut de France, Paris.
SHFJ/CEA Orsay in the frame of the cooperation through IFR 49 INSERM/CNRS France.
Key points :
Posterior Basicranium (PBA), divided in 2 parts joined to the foramen magnum, presents a
torque in Idiopathic scoliosis (IS)
PBA torque reflects cerebellar asymmetry in IS.
PBA torque induces spatial asymmetry of the vestibular system and specially, of the otolithic
system, with potential consequences on vestibular function and posture in IS.
PBA asymmetry and idiopathic scoliosis
Are there neuro-anatomical abnormalities associated with idiopathic scoliosis (IS)?
Posterior Basicranium (PBA) reflects cerebellum growth and contains vestibular organs, two
structures suspected to be involved in scoliosis.
The aim of this study was to compare posterior basicranium asymmetry (PBA) in Idiopathic
scoliosis (IS) and normal subjects.
Method: To measure the shape of PBA in 3D, we defined an intra-cranial frame of reference
based on CNS and guided by embryology of the neural tube. Measurements concerned three
directions of space referred to a specific intra cranial referential. Data acquisition was
performed with T2 MRI (G.E. Excite 1.5T, mode Fiesta). We explored a scoliosis group of 76
women and 20 men with a mean age of 17, 2 and a control group of 26 women and 16 men,
with a mean age of 27, 7.
Results: IS revealed a significant asymmetry of PBA (Pr>|t|<.0001) in 3 directions of space
compared to the control group. This asymmetry was more pronounced in antero-posterior
(AP) & lateral direction, forming a torque of the posterior base shape associated with identical
Discussion: IS Cerebellar and PBA asymmetries are neurodevelopmental anomalies involved
in IS. The vestibular systems are embedded in the 2-parted PBA and, therefore, are in
asymmetrical spatial position with potential consequences on otolithic function because this
latter is devoted to gravity.
In 2002, Kwak demonstrated links between patterning of the cerebellum and alterations in the
development of the internal ear in experimental zebra fish (focused on semi-circular canals
formation) We engaged a study on IS semi-circular canals anatomy thanks to a novel program
of modelling. We will report our first results in the companion paper.
Pba asymmetry and idiopathic scoliosis
According to a report by Nachemson,idiopathic Scoliosis (IS) is now generally recognized
to be caused by several conditions: genetic, [2, 3], hormonal [4, 5], neuro-anatomical [6, 7, 8]
and/or neuro-muscular [9, 10].
Various studies have reported links between IS and asymmetry at similar functional and
anatomical levels: Chockalingam , Shimode, Kramersand Perret have
reported right/left asymmetries at functional levels for gait or motor control parameters.
Geissele  and Kertesz have stressed the presence of links between IS and right/left
brain asymmetries. Geschwind & Galaburda  have highlighted asymmetries of the
temporal planum, with the left planum being more developed in 65% of examined brains.
In a study by Lundstrom  60 to75% of the examinated population has a left hemisphere
larger than the right. He measured the angle formed by a line drawn from the ear to the
median line. This anatomical detail has also been noted by Burke  who pointed out that
cause of this asymmetry is still unknown. More recently, neuro-anatomical abnormalities in
the pontine and hindbrain regions have been clearly implicated, in IS, in a report by Lowe
 in 2000.
Pirttiniemi, Lahtela, Hunggare & Serlo, Delaire, Berthoz &Rousié [22,23] have
reported the presence of craniofacial asymmetry(CFA) in certain cases of scoliosis and /or
laterocolis. These asymmetries are associated with spatial asymmetries of vestibular organs
involved in postural control.
CFA implicates asymmetry of each bony component of the head: vault, face and basicranium.
The basicranium is divided in three parts: the anterior part, the middle part which is a true
patella which makes the 3D movements of the two other parts possible and the posterior part
in which the labyrinths are embedded.
The basicranium shape reflects the underlying brain growth. Cerebral asymmetry appears, in
utero,at the beginning of the third week. At this stage, the basicranium is a pre-cartilaginous
and flexible structure: the three parts of the base are separated by large and mesenchymal
synchondrosis avoiding any pressure that could affect the brain growth [24, 25]. It is therefore
obvious that no basicranium asymmetry would occur without cerebral asymmetry.
The aim of this study was to compare the shape of the posterior basicranium (PBA) on IS and
non-IS subjects. This study was conducted for two reasons: 1) the PBA reflects the growth of
the cerebellum, the asymmetry of which is though to be implicated in scoliosis [19, 26] and 2)
the PBA contains vestibular organs implicated in postural disorders .
Materials and Methods
MRI acquisition and measurement of basicranium asymmetries
Data, in all MRI machines are included in a volume, which is itself included in the reference
frame of the machine. Three dimensional-coordinates of a selected point (voxel) are
calculated from this frame and are dependent on the patient‟s head orientation in the machine.
Precise measurements require a reliable frame of reference, apart from the patient head
orientation during the acquisition. These measurements should allow comparison of the
spatial location of head paired structures in a subject but also between different subjects.
We used an intra-cranial frame of reference based on the central nervous system .
We assigned our reference points on the basis of embryology: the neural tube stage marks the
beginning of the cranio-caudal orientation of the embryo especially at the cerebral level. This
stage is also the epicenter of brain-lobes growth and at this stage, asymmetry is not yet
The neuro sagittal medial plan (NSM), (red plan in Figure 1)-is built from points located on
the axis upon which this embryonic neural tube was fastened: two points are taken
successively along on the fundus of the third-ventricle (mesencephalon) and one point is taken
at the level of the cerebral aqueduct joining the third to the fourth ventricle (see Figure 2A, B,
The axial plan-(blue plan in Figure 1)- is perpendicular to NSM plan and goes through the CA
(anterior commissure)-to CP (posterior commissure) axis which provides the principal point
of reference in Talairach‟s atlas . Thus, to build this plan, we used the three following
points: CA, CP and the point where CA-CP axis crosses the sagittal plan.
The frontal plan-(green plan in Figure 1B) - is perpendicular to the previous ones.
After constructing this frame of reference; it became possible to compare the 3D location of
paired structures of the head.
The PBA is divided into two parts: the left and right petrous pyramids joined to the foramen
magnum. We used the junction between the auditory meatus and the three vestibular semi-
circular canals as markers to measure the spatial position of each part. These points, named P
(right) & P‟ (left)-and situated inside the PBA, are precise and easy to find. (See Figure
Data acquisition was performed with EXCITE MRI 1.5T., from General Electric,
using a head coil. A T2-weighted sequence was used in 3D FIESTA mode acquisition Thus,
PBA structures were analysed in a volume instead of classical MRI slices. The quality of data
was monitored by a G.E. work station 4.1 and stored on a CD.
We processed the data using various modules of Brainvisa which is free access software
devoted to MRI available on the web (http://brainvisa.info/).
Various steps of the process:
1-Import and convert MRI data (Dicom format) given by the GE machine to „Gis
Brain visa‟ format.
2- Select and save points needed for the construction of the reference frame. For each
chosen point, a module of Brainvisa called Anatomist 1.3 provides 3D coordinates referenced
to the reference frame of the MRI machine.
3- Select and save the markers points P (right) and P‟ (left).
4- Plans and distances :we automated the following procedure in a novel program in
order to measure the 3D location of P&P ‟referenced on our reference frame: in a
mathematical method, we calculate the equation of the planes using Cartesian coordinates of
three distinct points : A(xA, yA ,zA), B(xB,yB,zB) et C(xC,yC,zC)
The equation of plan is: ax + bx+ cz +d=0. The program automatically calculates the
distances of these three points to the plans.
By measuring the distance differences between P and P‟-to each of the 3 planes, we can
define the spatial orientation of both parts of the PBA:
1) to the NSM plane = dP_sag – dP‟_sag, 2)to axial plane =dP_axial – dP‟_axial, 3) to the
frontal plane = dP_front – dP‟front. These distances are given in millimeters.
We used a similar procedure for each patient for establishing inter-patients comparisons.
Pba asymmetry and idiopathic scoliosis
Patients and control subjects
No data was available in relation to PBA evaluation in IS patient at the time of the planning:
thus the sample size could not be estimated before hand. The number of IS patients was fixed
between 80 and 100 because some abnormalities may be uncommon in the studied IS
population and also because classical statistical analyses related to categorical variables
require such sample size. The number of controls was kept to 30 as the Student‟s t-test has
been shown to be robust when the sample size is not too small.
a) Control group (CG)
Justifying a MRI for healthy individuals was difficult: thus, control subjects were recruited
from patients undergoing maxillo-facial consultation and suffering from lesions of the
temporomandibular joints which are similar to our regions of interest. These lesions do not
interfere with spine or PBA and these patients can be included as normal control subjects. We
exploited, their MRI results, which have been carried through in the context of their
therapeutic treatment. The criteria for inclusion were strictly observed: patients were required
to be free of any spine deformation, whether congenital or acquired which was confirmed by
the rheumatologists of our team. All of these subjects were consenting to give their MRI and
spine data (spine radiographies) in an anonymous way for the study.
This control group (CG) included 33 persons, 27 women and16 men, ranging in age from 8 to
51 years with a mean age of 27, 7 years (std. dev: 5.6).
106b) Scoliosis group (SG)
For the scoliotic group (SC), the exclusion criteria were to be free of acquired or congenital
spine lesion, of visual or auditive malformation which could have postural incidences and of
systemic illness. IS patients have been recruited from patients treated by physiotherapy and/or
brace by rheumatologists of our team (hospital or clinics). The recruitment was time-
randomized (23months): patients, presenting the inclusion criteria, were asked to participate
to the study as they came along to consultations. MRI was prescribed, in the course of their
therapeutic treatment to control malformations or lesions in the skull base or cervical spine
(which could also be exclusion criteria).They gave their consent to give their MRI and spine
data, in anonymous way, for the study.
SG included 95 patients, 75 females and 20 males, ranging in age from 10 to 30 with a mean
age of 17.3 (Std. dev.: 4.7).The greater number of females reflects the well-known large
incidence of idiopathic scoliosis on female.
Their scoliosis was classified following two criteria
1 –Cobb angle: two sub-groups were distinguished according to the severity of the
curve: SG1: from 12 to 20 degrees, including 57 subjects with a mean age of 14, 8(std. dev.:
3.01). SG2: from 20 to 47degrees including 38 subjects with a mean age of 18, 9(std.dev. 3,
2- Location of the deformation along the spine according to the Cottalorda and Kohler
The randomized recruitment, spread over 23 months, allowed us to divide the same 95
patients in three sub-groups:
- 57 patients with a thoracolumbar deformation formed the TL subgroup (52 with left TL and
5 with right TL)
- 24 patients with a thoracic deformation formed the T subgroup (22 with right T and 2 with
- 14 patients with a lumbar deformation formed the L subgroup (13 with left L and 1 with
We evaluated the reliability of our method by testing the reproducibility of our results with
test-retest correlation (RO-intra) using the Fermanian Intra-class correlation reported by Fleiss
. The Fermanian scale of evaluation is as follows: RO>0.91= very good;
0.71<RO<0.91=good; 0.51<RO<0.71= moderated.
We measured the dP-dP‟distances to the NSM, frontal and vertical planes.
As recommended in the method, these measurements were carried out three times. Thus, for
each subject, we collected nine measurements. This evaluation was carried out using 26
We obtained the following results:
To the NSM, RO=0.97752 with an inferior limit=0.94739, sup. Limit=0, 99048; Estimation=
To the frontal plane RO=0, 97872, inferior limit=0, 95014, sup. Limit=0, 99099;
To the vertical plane RO= 0, 93930, inferior limit=0, 86152, sup. Limit= 0, 97401;
Estimation= very good.
All statistical analysis was performed by means of SAS software (SAS Institute Inc.
Cary, NC 25513). P values<0.05 were considered statistically significant. Results were
expressed as the mean, standard deviation and range .The assumption of equal variances was
tested using the Fisher‟s test. The student‟s test was used because this assumption was not
Comparison between normal and scoliosis Basicranium asymmetries
IS patients (SG) presented significantly greater asymmetry of the PBA orientation in 3
directions of space than the control group (CG)
-Frontal plane: in SG, dP-dP‟ (mean value) = 5,662mm, Pr>|t|<.0001;
in CG, dP-dP‟ (mean value) = 2,140mm, Pr>|t|<.0001
-NSM plane: in SG, dP-dP‟ (mean value) = 3,573mm, Pr>|t|<.0001
in CG, dP-dP‟ (mean value) = 1,945mm, Pr>|t|<.0001
-Vertical plane: in SG, dP-dP‟ (mean value) =3,516mm, Pr>|t|<.0001
in CG, dP-dP‟ (mean value) =1,264mm, Pr>|t|<.0001.
We determined the right /left asymmetry of the 2-parted PBA, by establishing the
following differences: dP- dP‟negative, in relation to the NSM plane, meant that P was closer
than P‟. dP- dP‟ negative in relation to the horizontal plane, meant that the P was lower and
dP-dP‟ negative, in relation to the frontal plane, meant that P was backward. Measurements
were only calculated for the SG group.
We found: the right part of the PBA referenced to the frontal plane, backward in 66/95(69,
4%). The right part of the PBA referenced to the NSM plane was laterally closer than the left
one in 54/95(56, 8%). And, referenced to the horizontal plane, the right part was lower than
the left one in 73/95(76, 8%). Indirectly, this PBA torque suggested that underlying
cerebellum was, most of the time, larger on left side.
The purpose of this study was to verify the association between scoliosis and PBA.
Our first result was methodological in which we proposed a novel technique for analyzing
scoliosis: an intracranial frame of reference built from the NSM plane, automated in a
programme for identifying the asymmetry proved to be a reliable tool due to statistical
analysis. This technique may be useful for diagnosis in radiology but also for fundamental
studies in development.
The relation between scoliosis and posterior basicranium asymmetries
Our second result was in relation to our suggestion that scoliosis patients, in
comparison with normal subjects are afflicted with a significant asymmetry of the posterior
basicranium(figure 4). Interestingly, even with non-scoliotic control subjects, this part of the
base shows weak asymmetry which is consistent with other studies of brain and skull
asymmetries [32, 33] Coffin , reported similar observations in 1986, and speculated that
this asymmetry might have started during the first three months; this is because at this stage,
the basicranium is still flexible and open to changes in its shape depending on brain growth.
The “normal pattern” we obtained, provides the limits for normality and a preliminary scale of
comparison. However, it would be necessary to increase the number of subjects to refine the
pattern exhibited by our study with other similar groups.
IS versus control subjects revealed a significant antero-posterior and weak dorso-
ventral movement of the posterior base following asymmetrical brain growth.
Our results were also in accord those of Villemann (1976)  who confirmed that impact of
neural mass growth can modify the spatial orientation of the basicranium; In our study, we
highlighted that the two aisles of PBA form a torque around the foramen magnum. Recent
MRI scans confirm our findings: in 2006, Lancefield  found that brain torque may be
observed in the latter part of foetal life. IS patients show an exaggeration of this torque.
Similarly, Lacy and Horner (1996) have also demonstrated that “asymmetry” can be
considered as a threshold phenomenon in cases of genetic and /or environmental
modifications: they observed that skull and skeletal asymmetries increased with genetic
transmission in the last few populations of rats that have been maintained under abnormal
living conditions . Morever, Lowe  has suggested a possible implication of the
midbrain or hindbrain in IS. The cerebellar torque we found is also associated with an
asymmetry between the right and left part of the cerebellum. A question remains whether the
cerebellum asymmetry could be involved through its spatial organisation or its cortical
function. Further studies could be engaged.
In the method we differentiated IS group in SG1 and SG2 subgroups for a better
presentation of IS patients. One could wonder if the severity of the spine deformation is
related to the amplitude of the PBA torque. We did not lead this comparison because, in the
course of the study, we discovered a bias between these two subgroups: the mean age of the
patients in SG1 and SG2 was, respectively, 14.8 and 18.9. In SG1, patients were younger and
IS were still progressive forbidding the comparison. We should lead linear study to shed some
light on this question.
Pba asymmetry and idiopathic scoliosis
This study linked face asymmetry to basicranium asymmetry: temporo-mandibular joints
hang the mandible to the posterior basicranium. This is expressed on the face and can easily
be verify visually by simply assessing the implantation of the IS patient‟s ears and eyes during
the clinical examination of the face. At the bones level of the face, PBA frequently,induces
asymmetry in orbits location, deviation of the nasal septum, jaw and zygomatic arch
asymmetry. This observation was previously reported by Burke 1992 Chebib and
Chamma 1981, Lundstrom 1961 and especially Previc in 1991  who carried out
an extensive study of cranio-facial asymmetries confirming the association between scoliosis
and cephalic asymmetry – although without making use of any other comparative methods.
The second part of our study on the PBA concentrated on the vestibular system which
is widely though to be implicated in IS. The asymmetrical spatialization of the PBA aisles in
which the labyrinths are embedded, suggests functional consequences as a result on vestibular
function. The otolithic system which is a gravity devoted system could be responsible for
passing asymmetrical information to the postural system. Previc (1991) (40),Bacsi (2004)(27)
have stressed the contribution of vestibular asymmetry in postural disorders and on the
asymmetry of the vestibulospinal reflex. Recently, Burwell (2006)  suggested that
neurodevelopmental anomalies were implicated in CNS body schema and may be the primary
in of idiopathic scoliosis. We are currently studying IS otolithic function
IS cerebellum and PBA asymmetries are neurodevelopmental anomalies. In 2002,
Kwak showed with zebra fish that the experimental „Valentino‟mutation disturbed the
patterning of the cerebellum with, as a secondary consequence, alterations in the development
of the internal ear due to poor expression of the fibroblastic factor fgf3. In 2004, Philips 
confirmed the implication of factors fgf3 and fgf8 in the formation of the cerebellum and otic
placodes. More, Riley in 2003, has discovered that cells abutting the posterior lateral
hindbrain coordinates the early patterning of the inner ear giving to the fore the close relation
between the hindbrain and the vestibular system 
The fact that fibroblastic factors figure equally in the formation of inner ear,
cerebellum and Base suggests an identical co-involvement, in IS. We therefore designed a
novel method for visualizing the anatomy of the vestibular system and more precisely that of
the membranous semi-circular canals. The first results will be published in a compagnon
1. Nachemson A., Sahlstrand T: Etiologic factors in adolescent idiopathic scoliosis, Spine 1977, 2
2. Bashiardes S, Veile R, Allen M et al.: SNTG1, the gene encoding gamma1-synthrophin: a
candidate for idiopathic scoliosis, Hum.Genet.2004 Jun; 115(1):81-9
3. He HL, Wu ZH, Zhang JG et al.: Primary study on collagen X gene expression in the apical disc
of idiopathic scoliosis, Zhonghua Yi Xue Za Zhi 2004 Oct 17;84(20):1681-5
4. Machida M, Dubousset J, Satoh T et al.: Pathologic mechanism of experimental Scoliosis in
pinealectomized chickens, Spine 2001 Sept.; 26(17):E385-91
5. Dubousset J, Machida M: Possible role of the pineal gland in the pathogenesis of idiopathic
scoliosis. Experimental and clinical studies; Bull Acad. Nat Med. 2001; 185 (3):593-602;
6. Yamada K, Yamamoto H, Nakagawa Y et al.: Etiology of idiopathic scoliosis, Clin Orthop.,
1984 Apr ;( 184):50-7.
7. Yamamoto H, Yamada K: Equilibral approach to scoliosis posture Agressologie, 1976; 17:61-66.
8. Burwell RG, Dangerfield PH: Etiologic theories of idiopathic scoliosis: neurodevelopmental
concepts of maturational delay of the CNS body schema, Stud Health Inform.2006; 123:72-9.
9. Inoue M, Minami S, Nakata Y et al.: Preoperative MRI study analysis of patients with idiopathic
scoliosis, a prospective study, Spine 2005 Jan 1;30(1):108-14
10. Perret C, Robert J: Electromyographic responses of paraspinal muscles to postural disturbance
with special reference to scoliotic children, J. manipulative Physiol. Ther. 2004, Jul-Aug;
11. Chockalingam N, Rahmatalla A, Dangerfield P et al.: Kinematic differences in lower limb gait
analysis of scoliotic subjects, Stud Health Technol Inform. 2002; 91:173-7.
12. Shimode M, Ryouji A, Kozo N: Asymmetry of premotor time in the back muscles of adolescent
idiopathic scloliosis, Spine 2003 Nov 15; 28 (22):2535-9.
13. Kramers-De Quervain IA, Muller R et al. Gait analysis in patients with idiopathic scoliosis, Eur
Spine J.2004 Aug ; 13(5) :449-56.Epub2004 Apr3.
14. Geissele AE: Magnetic resonance imaging of the brain stem in adolescent idiopathic scoliosis;
Spine 1991 Jul; 16 (7):761-3.
15. Kertesz A, PolkM: Anatomical asymmetries and functional laterality, Brain 115:589-605
16. Geschwind N & Galaburda IS: Cerebral lateralization. Biological mechanisms, association and
pathology: A hypothesis and a program for research. Arch. of neurology, 1985. 42: 428-459
17. Lundstrom A: Some asymmetries of the dental arches, jaws and skull and their etiological
significance. Am. J. of orthodontics, 1961, 47:81-106.
18. Burke PH: Serial observation of asymmetry in the growing face. Br.J. orthod. 1992 Nov; 19(4):
19. Lowe TG, Edgar M, Margulies JT et al..: Etiology of idiopathic scoliosis: Current Trends in
Research, JBJS 2000; 82A; 8:1157-1168.
20. Pirttiniemi P, Lathela P, Huggare J et al.: Head position and dentofacial asymmetries in surgical
and treated muscular torticollis patients, Acta Odontologica Scandinavica, 47: 193-197.
21. Delaire J: Syndromes malformatifs craniofaciaux in traité de pathologies buccales et
maxillofaciales, De Boeck University, Bruxelles, ed.91, 2.
22. Berthoz A., Rousié D: Physiopathology of Otholith-Dependent Vertigo, contribution of the
cerebral cortex and consequences of cranio-facial asymmetries, Adv. in ORL, 58, p. 48 – 67,
23. Rousie D., Hache J.C., Pellerin P., Deroubaix J.P., Van Tichelen P., Berthoz A., Oculomotor,
Postural, and Perceptual Asymmetries Associated with a Common Cause: Craniofacial
Asymmetries and Asymmetries in Vestibular Organ Anatomy , Ann. of N.Y. Acad. of Sc., 871,
p. 439-446, 1999
24. Burdi R.:Early development of the Human Basicranium: its morphogenic controls, growth
pattern and relations, in , in Development of the Basicranium 1976,ed by Bosma J., DHEW 76-
989 NIH; ch5:81-92.
25. Couly G: Croissance craniofaciale du foetus et du jeune enfant, Développement céphalique,
ed.Cdp Paris, ch 3 ; 69-101.
26. Kertesz A, PolkM: Anatomical asymmetries and functional laterality, Brain 115:589-605
27. Bacsi AM, Colebatch JG: Evidence for reflex and perceptual vestibular contribution to postural
control, Exp. Brain Res. 2004 Aug 18.
28. Rousié D., Asymétries crânio-faciales et système oculo-labyrinthique, Thèse de Sciences de la
vie, Faculté de Médecine de Lille, Université Lille II, 1999
29. Talairach J, Tournoux P.: Referentially oriented cerebral MRI anatomy, Thieme medical New
30. Cottalorda J, KohlerR: Recueil terminologique de la Scoliose, Rachis 1997; 9:91-97
31. Fleiss JL: The design and analysis of clinical experiments, 1986, N.Y., John Wiley& Sons.
32. Le May M: Morphological cerebral asymmetries in Modern, fossil and non human primate,
J.Comput. Assist. Tomogr. 1978 Sept.; 2(4): 471-6.
33. Livshits G, Kobbylianski E.: Fluctuating asymmetry as a possible measure of developmental
homeostasis in Human. Human Biol. 1991 Aug. 63(4): 441- 466.
34. Coffin G.S.: Asymmetry of the Human Head: clinical observations, Clinical Pediatrics, 25:230-
35. Villeman H.:The growth of the cranial Base in the rat, in Development of the Basicranium
1976,ed by Bosma J., DHEW 76-989 NIH; ch 28:511-514
36. Lancefield K, Nosarti Ch, Rifkin L: Cerebral Asymmetry in 14 years olds born very preterm,
Brain research, May 2006: 33-39.
37. Lacy RC, Horner BE: effects of inbreeding on skeletal development of rattus villosimus; J.of
Heredity 1996 Jul-Aug; 87(4): 277-87.
38. Chebib FS& Chamma A M: Indices of craniofacial asymmetry, The Angle Orthodontist, 1981;
39. Previc FH: A general Theory concerning the Prenatal Origins of cerebral lateralization in
Humans, 1991, Psychological Review, 98,3: 299-334
40. Kwak SJ, Phillips BT, Heck R et al.: An expended domain of fgf3 expression in the hindbrain of
zebrafish valentine mutants results in mis-patterning of the otic vesicle, Development 2002 Nov;
41. Phillips BT, Storch EM, Lekven AC et al..: A direct role for fgf but not Wnt in otic placode
induction, Development 2004 Feb; 131(4): 923-31.
42. Riley Br, Phillips BT: Ringing in the new ear: resolution of cells interactions in otic development
in Developmental Biology, vol261, Issue 2, 15 Sept 2003: 289-3
Titles & legends of figures
Figure 1 the intracranial frame of reference
View of the referential included in a 3D reconstruction of the head. With this referential the
measurements are independent of the head‟s patient orientation during MRI and it allows
inter-subjects PBA comparisons.
Red plane=sagittal plane used for lateral measurements, blue plane= axial plane used for
vertical measurements, green plane= frontal plane used for anteroposterior measurements
Figure 2 : A Axial view
The fundus of the third ventricle is easily identified on this axial view. The crossing lines
point corresponds to the first selected point located on the third ventricle. Its 3D coordinates
are automatically transmitted to the programme.
Figure 2B : Medial-sagittal view
On this medial-sagittal view the same selected point appears on the fundus of the third
ventricle. This view permits to control the validity of our selected point.
Figure 2C & 2D : Medial-sagittal view and selected points
These two views show the two others selected points which are required to create the medial
axial plane of the referential.
Figure 3A & 3B : Selection of P& P‟ points
The junction between the auditory meatus and the three vestibular semi-circular canals are
selected as markers to measure the spatial orientation of the two PBA petrous parts. The black
arrows indicate these junctions, named P (right) (3B) & P‟ (left) (3A) situated inside the PBA.
They are precise and easy to find. The asymmetries of the cerebellum and PBA torque
deformation appear on these two axial views.
Figure 4 : Symmetrical PBA of a non-IS subject
This control subject presents a symmetrical PBA. The cerebellum is symmetrical. P&P‟ are
located on the same horizontal line.
Figure 5 : X-Rays Thoraco-lumbar scoliosis
This patient was the one afflicted with PBA asymmetry detailed in figure 3A & 3B. The
asymmetry was calculated with our programme: dP-dP‟= - 4. 32mm in relation to the frontal
plane, meant that P was backward (AP asymmetry); dP- dP‟= - 2.54mm in relation to the
NSM plane, meant that P was closer than P‟ and dP- dP‟= - 3,89mmin relation to the
horizontal plane, meant that the P was lower than P‟. These different results measure the
torque deformation of PBA.