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The aim of the current study was to establish whether the vertebral morphometry (e.g., vertebral body width and spinal canal diameters) is associated with degenerative lumbar spinal stenosis (DLSS). A retrospective computerized tomography (CT) study from L1 to L5 for two sample populations was used. The first included 165 participants with symptomatic DLSS (sex ratio 80 M/85F), and the second had 180 individuals from the general population (sex ratio: 90 M/90F). Vertebral body length (VL) and width (VW) were significantly greater in the stenosis males and females compared to their counterparts in the control. The mean VL in the stenosis males was 31.3 mm at L1, 32.6 mm at L2, 34 mm at L3, 34.1 mm at L4, and 34.5 at L5 compared to 29.9 mm, 31.3 mm, 32.6 mm, 32.8 mm, and 32.9, respectively, in the control group ( P ≤ 0.003). Additionally, the bony anterior-posterior (AP) canal diameters and cross-sectional area (CSA) were significantly smaller in the stenosis group compared to the control. The mean AP canal values in the stenosis males were 17.8 mm at L1, 16.6 mm at L2, 15.4 mm at L3, 15.6 mm at L4, and 16.1 at L5 compared to 18.7, 17.8, 16.9, 17.6, and 18.8, respectively, in the control group. Vertebral length (OR-1.273 to 1.473; P ≤ 0.002), AP canal diameter (OR-0.474 to 0.664; P ≤ 0.007), and laminar inclination (OR-0.901 to 0.856; P ≤ 0.025) were significantly associated with DLSS. Our study revealed that vertebral morphometry has a role in DLSS development., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Janan Abbas et al.)

The aim of this study is to determine the sagittal inclination of lumbar spinous processes (SPs) in individuals with degenerative lumbar spinal stenosis (DLSS). It is a retrospective computerized tomography (CT) study including 345 individuals divided into two groups: control (90 males, 90 females) and stenosis (80 males and 85 females. The SP inclination was measured in the midsagittal plane from L1 to L5 levels. Stenosis males (L3-L5) and females (L1, L4) manifested significantly greater SP inclination compared to their counterparts in the control group. Males had significantly horizontal SP orientation compared to females (L1, L2). We also found that SP inclination became steeper as we descend caudally. This study indicates that SP inclinations are significantly associated with DLSS., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Janan Abbas et al.)

The aim of this study is to establish whether facet tropism (FT) and orientation (FO) are associated with degenerative lumbar spinal stenosis (DLSS). A retrospective computerized tomography (CT) study including 274 individuals was divided into two groups: control (82 males and 81 females) and stenosis (59 males and 52 females). All participants have undergone high-resolution CT scan of the lumbar spine in the same position. FT and FO were measured at L1-2 to L5-S1. Significant sagittal FO was noted in the stenosis males (L2-3 to L4-5) and females (L2-3 to L5-S1) compared to the controls. The prevalence of FT was remarkably greater in the stenosis males (L4-5, L5-S1) and females (L3-4, L5-S1) compared to their counterparts in the control group. Our results also showed that FT (L3-4 to L5-S1) increases approximately 2.9 times the likelihood for DLSS development. This study indicates that FO and FT in the lower lumbar spine are significantly associated with DLSS., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Janan Abbas et al.)

The aim of this study was to compare pedicle dimensions in degenerative lumbar spinal stenosis (DLSS) with those in the general population. A retrospective computerized tomography (CT) study for lumbar vertebrae (L1 to L5) from two sample populations was used. The first included 165 participants with symptomatic DLSS (age range: 40-88 years, sex ratio: 80 M/85 F), and the second had 180 individuals from the general population (age range: 40-99 years, sex ratio: 90 M/90 F). Both males and females in the stenosis group manifested significantly greater pedicle width than the control group at all lumbar levels ( P < 0.05). In addition, pedicle heights for stenosis females were remarkably smaller on L4 and L5 levels compared to their counterparts in the control group ( P < 0.001). Males have larger pedicles than females for all lumbar levels ( P < 0.001). Age and BMI did not demonstrate significant association with pedicle dimensions. Our outcomes indicate that individuals with DLSS have larger pedicle widths than the control group. More so, pedicle dimensions are gender-dependent but independent of age and BMI., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Janan Abbas et al.)

The aim of this study was to shed light on the association between lumbosacral transitional vertebra (LSTV) and degenerative lumbar spinal stenosis (DLSS). A cross-sectional retrospective study was performed on 165 individuals that were diagnosed with clinical picture of DLSS (age range: 40-88 years; sex ratio: 80M/85F) and 180 individuals without DLSS related symptoms (age range: 40-99 years; sex ratio: 90M/90F). All participants had undergone high-resolution CT scan for the lumbar region in the same position. We also used the volume rendering method to obtain three-dimensional CT images of the lumbosacral area. Both males and females in the stenosis group manifest greater prevalence of LSTV than their counterparts in the control group (P<0.001). Furthermore, the presence of LSTV increases the likelihood of degenerative spinal stenosis (odds ratio= 3.741, P<0.001). In the control group, LSTV was more common in males, and sacral slope angle of males was significantly greater in LSTV group compared to non-LSTV. This study indicates that LSTV was significantly associated with symptomatic DLSS.

The aim of this study was to reveal whether demographic aspect, vertebral morphometry, and spine degeneration are associated with lumbar Schmorl's nodes (SNs). A retrospective cross-sectional study was performed using data from the Department of Radiology (Carmel, Medical Center, Israel) for 180 individuals: age range between 40 and 99 years; 90 males and 90 females. All participants had undergone high-resolution CT scans for abdominal diagnostic purposes in the same supine position prior to our study, which enabled the processing of the scans in all planes and allowed a 3D reconstruction of the lower lumbar region. Eighty individuals (44.4%) had at least one SN along the lumbar spine, particularly at L3-4 level (30%). Vertebral body length (L1 to L3) and width (L1 and L4) were significantly greater in the SNs group compared to non-SNs group. On contrast, disc height (L3-4 and L4-5) was significantly lesser in SNs group than non-SNs group. SNs was significantly associated with smoking ( X 2 = 4.436, P=0.02) and degenerative lumbar spinal stenosis ( X 2 = 5.197, P=0.038). Moreover, the prevalence of SN was significantly greater in individuals with vacuum phenomenon and osteophytes formation (L1-2 to L4-5 levels). This study indicates that vacuum phenomenon on L3-4 (OR: 4.7, P=0.034), smoking habit (OR: 3.2, P=0.003), disc height loss of L4-5 (OR: 0.798, P=0.008), vertebral body length of L1 (OR: 1.37, P<0.001), and age (OR: 1.05, P=0.002) increase the probability of developing lumbar SNs.

Background: Degenerative lumbar spinal stenosis (DLSS) is a common health problem in the elderly and usually associated with three-joint complex degeneration. Schmorl's nodes (SNs) are described as vertical herniation of the disc into the vertebral body through a weakened part of the end plate that can lead to disc degeneration. Since SNs can harm the spine unit stability, the association between DLSS and SNs is expected. The aim of this study is to shed light on the relationship between degenerative lumbar spinal stenosis and SNs., Methods: Two groups of individuals were studied: the first included 165 individuals with DLSS (age range: 40-88, sex ratio: 80 M/85 F) and the second 180 individuals without spinal stenosis related symptoms (age range: 40-99, sex ratio: 90 M/90 F). The presence or absence of SNs on the cranial and caudal end plate surfaces at the lumbosacral region (from L1 to S1 vertebra) was recorded, using CT images (Brilliance 64 Philips Medical System, Cleveland Ohio, thickness of the sections was 1-3 mm and MAS, 80-250). Chi-Square test was taken to compare the prevalence of SNs between the study groups (control and stenosis) by lumbar disc level, for each gender separately. Multivariable logistic regression analysis was also used to determine the association between DLSS and SNs., Results: The prevalence rate of SNs was significantly greater in the stenosis males (L1-2 to L5-S1) and females (L4-5 and L4-S1) compared to their counterparts in the control (P < 0.001). In addition, the presence of SNs in both males and females was found to increase the likelihood for DLSS., Conclusions: Our results indicate that SNs prevalence is significantly greater in the DLSS group compared to the control. Furthermore, SNs are strongly associated with DLSS.

Background: The condition of paraspinal muscles is known to be associated with some variables such as age, gender, and low back pain. It is generally agreed that these muscles play an important role in the stability and functional movements of the lumbar vertebral column. Although spinal instability has been shown to play an essential role in degenerative lumbar spinal stenosis (DLSS), the role of paraspinal muscles remains elusive. The main purpose of this study was to shed light on the relationship between the condition of paraspinal muscles and symptomatic DLSS., Methods: Two sample populations were studied. The first included 165 individuals with DLSS (age range: 40-88, sex ratio: 80 M/85 F) and the second 180 individuals without spinal stenosis related symptoms and low back pain (age range: 40-99, sex ratio: 90 M/90 F). Measurements were taken at the middle part of L3 vertebral body, using CT axial images (Philips Brilliance 64). Muscles density was measured in Hounsfield units (HU) using a 50 mm 2 circle of the muscle mass at three different locations and the mean density was then calculated. The cross-sectional area (CSA) was also measured using the quantitative CT angiography method. Analysis of Covariance (adjusted for body mass index and age) was performed in order to determine the relationship between the condition of paraspinal muscles and symptomatic DLSS., Results: Individuals in the stenosis group had higher muscle density as compared to the control group. The CSA values for the erector spinae (both sexes) and psoas (males) muscles were significantly greater in the stenosis group as compared to their counterparts in the control group. Additionally, density of multifidus (both sexes) and erector spinae (males) muscles was significantly associated with symptomatic DLSS., Conclusions: Our results show that individuals with symptomatic DLSS manifest greater paraspinal muscles density and CSA (erector spinae), compared to the control group. Density of multifidus increases the likelihood of symptomatic DLSS.

Background: Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females., Methods: Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height., Principal Findings: Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined)., Conclusions: Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis). The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.

Study Design: A descriptive study of the association between demographic factors, and physical characteristics, and degenerative lumbar spinal stenosis (DLSS)., Objective: To shed light on the association between socioeconomic parameters, physical characteristics, and DLSS., Summary of Background Data: Lumbar spinal stenosis is a prevalent and disabling condition in the aging population. DLSS is considered to be the most common type and is essentially associated with disc disease, facet joint arthrosis, ligamentum flavum thickening, and osteophyte formation. Although there is ample information regarding the association between body mass index, cardiovascular disorders, smoking habits, and disc disease, very little is known about their association with DLSS. Data on the association of body physique (e.g., height and weight) and DLSS are limited., Methods: Two sample populations were studied. The first included 165 individuals with DLSS (mean age, 64 ± 9.9 yr) and the second 180 individuals without spinal stenosis related symptoms (mean age, 62.5 ± 12.6 yr). An evaluation of the cross-sectional area of the dural sac and degenerative listhesis for all participants was performed using computed tomographic lumbar spine images, obtained by Philips EBW station (Brilliance 64, Philips Medical System, Cleveland, OH). All participants were interviewed to obtain demographic, physical, and health data. Independent t test, Mann-Whitney and χ tests were used to determine the association between parametric and nonparametric variables and DLSS. Logistic regression analysis was carried out to reveal predicting variables for DLSS., Results: Females with stenosis were significantly heavier and shorter than their counterparts in the control group. We also noticed that they delivered babies more often than those in the control group. Prevalence of individuals experiencing diabetes mellitus was significantly higher in the males with stenosis than control group. In the stenosis group, the frequencies of individuals engaged in heavy manual labor (males) and housekeeping (females) were significantly higher than that of their counterparts in the control group., Conclusion: Heavy manual labor and diabetes mellitus in males and housekeeping (females) play major roles in the genesis of DLSS.

Study Design: A descriptive CT study of lumbar facet joint (FJ) arthrosis in general and spinal stenosis populations., Objective: To reveal the prevalence of FJ arthrosis in general and stenosis populations and to establish its relationship to age and sex., Summary of Background Data: FJ arthrosis is a common radiographic finding and has been suggested as a cause of low back and lower extremity pain. It is also considered a dominant player in the genesis of lumbar spinal stenosis. Although it is well accepted that FJ arthrosis is an age dependent phenomenon, controversies still exist as to its association with sex and its prevalence at different spine levels. In addition, data on FJ arthrosis frequency in spinal stenosis population are missing., Methods: Two groups were studied. The first included 65 individuals with LSS (mean age = 66 ± 10 yr) and the second, 150 individuals (mean age = 52 ± 19 yr) without LSS related symptoms. Both left and right FJ arthrosis for each vertebral level (L3-S1) were evaluated on CT images (Brilliance 64, Philips Medical System, Cleveland, OH). Chi-square, Linear-by-Linear Association and McNemar test were carried out to reveal the correlation between FJ arthrosis and demographic factors (age, sex) and prevalence at different lumbar levels in both stenosis and nonstenosis groups. In addition, a two-way analysis of variance (ANOVA) was used to determine the association between body mass index (BMI) and FJ arthrosis., Results: The rate of FJ arthrosis at L3-L4 and L4-L5 were significantly higher (P < 0.001) in the stenotic group compared to the control. In the control group the prevalence of FJ arthrosis increases cephalocaudally (L3-L4 = 16%, L4-L5 = 28%, L5-S1 = 55%), whereas in the stenotic group there is a sharp increase from L3-L4 (27%) to L4-L5 (58%), but not from L4-L5 to L5-S1 (55%). No association between FJ arthrosis and sex was noted. Although, mean BMI was significantly smaller in the control group compared to the stenotic group, no association between BMI and facet arthrosis was found. In the general population the prevalence of FJ arthrosis at all three levels was greater for the right side; however, significant difference (P = 0.004) was obtained only for L3-L4. In all joints studied, the prevalence of FJ arthrosis increases considerably from the young age cohort (18-39) to the old age cohort (>60). Nevertheless, 10% of the young individuals (18-39) have already manifested FJ arthrosis at L5-S1. No arthrosis at that age was observed at L3-L4., Conclusion: FJ arthrosis is an age-dependent and BMI and sex independent phenomenon. In the general population, the prevalence of FJ arthrosis increases cephalocaudally with the highest frequency at L5-S1. In the stenotic group, the highest frequency was observed at the two caudal levels; L4-L5 and L5-S1. The prevalence of FJ arthrosis was greater for the right side.

Study Design: A descriptive study of the epiphyseal ring's structural design along the thoracolumbar spine., Objective: To characterize and analyze the shape and size of the epiphyseal ring, to better understand its function., Summary of Background Data: The literature is lacking in metrical data pertaining to the epiphyseal ring that is usually described as a narrow bony labrum on which the external fibers of the anulus fibrosus are anchored. Most researchers express doubts as to whether the term epiphysis is justified in this case., Methods: The sample studied included 240 human skeletons (vertebrae T4-L5) from a normal adult population (divided by sex, ethnicity, and age). Measurements of the vertebral body and epiphyseal ring were taken using a digital caliper at four different locations: anterior, posterior, right, left. In addition, each vertebral surface was photographed and the epiphyseal ring area measured (using image analyzer software Image J)., Results: We found that relative to vertebral body size throughout the thoracolumbar spine, the anterior section of the ring was the widest and the posterior section the narrowest. The lateral parts presented intermediate values. Relative to the discal area, the epiphyseal ring area gradually decreased from T7 to T12 and increased from T12 to L4. The area of the inferior ring was always larger than the superior ring (significant only for lumbar vertebrae), regardless of sex, ethnicity, and age., Conclusion: The epiphyseal ring varies largely in size and shape along the thoracolumbar spine. Much of its metrical properties are dictated by the applied mechanical stress regime during various movements, and/or the general anatomic structure of the spine.

As life expectancy increases, degenerative lumbar spinal stenosis (DLSS) becomes a common health problem among the elderly. DLSS is usually caused by degenerative changes in bony and/or soft tissue elements. The poor correlation between radiological manifestations and the clinical picture emphasizes the fact that more studies are required to determine the natural course of this syndrome. Our aim was to reveal the association between lower lumbar spine configuration and DLSS. Two groups were studied: the first included 67 individuals with DLSS (mean age 66 ± 10) and the second 100 individuals (mean age 63.4 ± 13) without DLSS-related symptoms. Both groups underwent CT images (Philips Brilliance 64) and the following measurements were performed: a cross-section area of the dural sac, vertebral body dimensions (height, length and width), AP diameter of the bony spinal canal, lumbar lordosis and sacral slope angles. All measurements were taken at L3 to S1. Vertebral body lengths were significantly greater in the DLSS group at all levels compared to the control, whereas anterior vertebral body heights (L3, L4, L5) and middle vertebral heights (L3, L5) were significantly smaller in the LSS group. Lumbar lordosis, sacral slope and bony spinal canal were significantly smaller in the DLSS compared to the control. We conclude that the size and shape of vertebral bodies and canals significantly differed between the study groups. A tentative model is suggested to explain the association between these characteristics and the development of degenerative spinal stenosis.

Study Design: A descriptive computed tomography (CT) study of the ligamentum flavum (LF) thickness in individuals with normal and stenotic lumbar spines., Objective: To establish standards for normal and pathologic range of LF thickness and its asymmetry as indicated in CT images and to examine its association with vertebral body size, age, and gender., Summary of Background Data: LF lines a considerable part of the posterior and lateral walls of the spinal canal and is a major role contributor to spinal canal stenosis. Due to methodologic deficiencies (e.g., small sample size, lack of control for vertebral body size, gender, and age), the normal range of LF thickness is still controversial. Furthermore, data on important aspect of LF thickness such as left-right differences are missing., Methods: Two groups of individuals were studied. The first group included 65 individuals with lumbar spinal stenosis (LSS) (mean age: 66 +/- 9.7 years) and the second, 150 individuals (mean age: 52 +/- 19 years) without LSS-related symptoms. LF thickness was measured on CT images (Philips Brilliance 64), obtained from axial plane scan at the intervertebral disc level. Measurements were performed at the levels of L3-L4, L4-L5, and L5-S1. Analysis of variance and t test were carried out to evaluate the association between LF thickness and demographic factors., Results: Absolute and relative LF thickness were significantly greater in the LSS group at the levels of L3-L4 and L4-L5 on both sides, compared to control group (P < 0.05). LF thickness was independent of gender (absolute and relative thickness). Even though LF thickness at all levels significantly increases with age, significant changes after the age of 60 occurred only at L3-L4. Significant asymmetry in LF thickness was found at L3-L4 (2.9 +/- 0.90 mm on the right vs. 2.76 +/- 0.90 mm on the left) and L5-S1 (3.42 +/- 1.1 mm on the right vs. 3.22 +/- 1.22 mm on the left) (P < 0.05)., Conclusion: LF thickness is an age-dependent and gender-independent phenomenon. LF is significantly thicker on the right side. The borderline between normal and pathologic LF thickness should not be set at 4 mm.

Although Schmorl's nodes (SNs) are a common phenomenon in the normal adult population, their prevalence is controversial and etiology still debatable. The objective was to establish the spatial distribution of SNs along the spine in order to reveal its pathophysiology. In this study, we examined 240 human skeleton spines (T4-L5) (from the Hamann-Todd Osteological Collection) for the presence and location of SNs. To determine the exact position of SNs, each vertebral body surface was divided into 13 zones and 3 areas (anterior, middle, posterior). Our results show that SNs appeared more frequently in the T7-L1 region. The total number of SNs found in our sample was 511: 193 (37.7%) were located on the superior surface and 318 (62.3%) on the inferior surface of the vertebral body. SNs were more commonly found in the middle part of the vertebral body (63.7%). No association was found between the SNs location along the spine and gender, ethnicity and age. This study suggests that the frequency distribution of SNs varies with vertebra location and surface. The results do not lend support to the traumatic or disease explanation of the phenomenon. SNs occurrences are probably associated with the vertebra development process during early life, the nucleus pulposus pressing the weakest part of the end plate in addition to the various strains on the vertebrae and the intervertebral disc along the spine during spinal movements (especially torsional movements).

Study Design: Quantitative lumbar magnetic resonance imaging (MRI) measurements in children were taken twice and analyzed for intra- and intertester reproducibility., Objective: To evaluate the reproducibility of a variety of lumbar quantitative measurements taken from MRIs of children from the general population., Summary of Background Data: The reproducibility of lumbar quantitative measurements has never been tested on MRIs of children from the general population. This is a prerequisite for a reliable anatomic characterization of the immature spine in normal and pathologic conditions., Methods: Lumbar quantitative measurements from 40 T2-weighted lumbar (L1-S1) MRIs of children from the general population were taken twice by 1 tester for intratester reproducibility and compared with the same measurements (L4-S1) of the same MRIs taken by a second tester for intertester reproducibility. The following parameters were measured using the iQ-VIEW system (IMAGE Information Systems Ltd., version 1.2.2, Plauen, Germany): Linear measurements--zygoappophyseal facets and interfacet widths, and vertebral body (VB), pedicle and intervertebral discs heights, widths, and lengths. Angular measurements--zygoappophyseal tranverse superior facet angles, sagittal VB, and disc wedging, lumbar lordosis, and sacral inclination. Statistical analysis included the concordance correlation coefficient (CCC), and Bland and Altman's limits of agreement (LOA)., Results: A total of 6160 measurements were analyzed. Good to excellent intratester reproducibility (0.75 < or =CCC < or =0.99) was indicated for all linear measurements (except for pedicle heights) (LOA: -4.76; 5.74 mm) and for angular measurements related to the facets orientation, lumbar lordosis, and sacral inclination (LOA: 11.22 degrees ; 12.34 degrees). VB and disc sagittal wedging manifested poor intratester reproducibility (CCC < 0.75). Good to excellent intertester reproducibility was indicated for 70% of all linear measurements (LOA: -5.83; 4.59 mm) and for all angular measurements in the lumbar spine (L4-S1) (LOA: -9.96 degrees ; 14.62 degrees) except for VB and disc sagittal wedging at L5 (CCC < 0.75)., Conclusion: Quantitative lumbar MRI measurements in children from the general population were found to be reproducible indicating a good visualization of immature vertebral anatomic margins on MRIs and an accurate definition of the measurement protocol.

Study Design: The shape and orientation of the thoracic and lumbar zygapophyseal facets at the T1-L5 level in children were measured and analyzed., Objective: To detect the pattern of zygapophyseal facet asymmetry in the thoracic and lumbar spines in children., Summary of Background Data: Whereas many studies have defined the pattern of zygapophyseal facet asymmetry in adults, there is insufficient data in children., Methods: A 3-dimensional digitizer was used to measure zygapophyseal facet size, topography (length, width, concavity, convexity, and lateral interfacet height), and orientation (transverse and sagittal facet angles) at the T1-L5 level. Thirty-two complete, nonpathologic skeletons of children (age range from 4 to 17 years), housed at the Hamman-Todd Human Osteological Collection (Cleveland Museum of Natural History, Cleveland, OH) were assessed. Statistical analysis included paired t tests and analysis of variance., Results: In general, zygapophyseal facet asymmetry in children exists only in the superior facets of the thoracic spine and is independent of age: The right superior facet is significantly shorter than the left in all thoracic vertebrae T1-T12 (up to -2.91 mm at T1), and significantly wider than the left in thoracic vertebrae T1-T9 (T8 excluded) (P < 0.003). The right superior transverse and sagittal facet angles are significantly greater than the left in thoracic vertebrae T1-T11, indicating a lesser inclination (in the sagittal plane) and more frontally positioned facet (in the transverse plane) (P < 0.003). Facet asymmetry was not evident in the superior or inferior facets of the lumbar vertebrae., Conclusion: Facet asymmetry in thoracic vertebrae appears in early childhood. The pattern of this asymmetry differs from that reported for adults and may be considered as a possible contributing etiological factor in the development of different types of idiopathic scoliosis.