Smadar Peleg

Range of Joint Movement in Female Dancers and Nondancers Aged 8 to 16 Years Anatomical and Clinical Implications

Background Little data are available on changes that occur with age in joint range of motion in dancers and nondancers. Hypothesis In dancers, joint range of motion will increase with age, whereas it will decrease in nondancers, independent of the joint studied. Study Design Cross-sectional study; Level of evidence, 3. Methods The study population included 1320 female dancers, aged 8 to 16 years, who participated in different types of dancing classes (classical ballet, modern dance, jazz, etc) and 226 nondancers of similar age. Range of motion was measured for the hip, knee, ankle, foot, and spinal joints. Results The pattern of differences in range of motion with age varied in different joints and types of movement. (1) For combined ankle and foot plantar flexion (pointe), ankle plantar flexion, and hip external rotation, there was no change in range of motion in dancers, whereas range of motion diminished with age in the nondancers. (2) For ankle dorsiflexion, neither group showed any change with age, and range of motion was significantly greater in the nondancer group. (3) For knee flexion, hip flexion, and hip internal rotation, range of motion decreased with age in both groups. (4) For hip abduction, range of motion decreased with age in dancers and remained constant in the nondancers. (5) For hip extension, range of motion increased in both groups. (6) For lower back and hamstrings, range of motion increased among dancers with age and remained constant among nondancers. Conclusion Dancers and teachers should realize that passive joint range of motion is unlikely to improve with age. Therefore, the major goal of a dancing program should focus on exercises that retain the natural flexibility of the dancers’ joints rather than trying to improve them.

Facet tropism and interfacet shape in the thoracolumbar vertebrae: characterization and biomechanical interpretation.

Study Design. Thoracolumbar facet and interfacet linear dimensions were measured and analyzed. Objective. To characterize and analyze the thoracolumbar facet and interfacet size and shape in relation to gender, ethnic group, and age and to detect the extent of normal facet tropism along the thoracolumbar spine. Summary of Background Data. Knowledge on facet tropism and interfacet shape is limited in the literature as most data are based on 2-dimensional measurements, small samples, or isolated vertebrae. Methods. Facet shape as represented by width, length, width/length ratio and interfacet distances was obtained directly from dry vertebrae of 240 adult human spines. The specimen’s osteologic material is part of the Hamann-Todd Osteological Collection housed at the Cleveland Museum of Natural History, Cleveland, OH. A total of 4080 vertebrae (T1–L5) from the vertebral columns of individuals 20 to 80 years of age were measured, using a Microscribe 3-dimensional apparatus (Immersion Co., San Jose, CA). Data were recorded directly on computer software. Statistical analysis included paired t tests and ANOVA. Results. A significant correlation was found between all thoracolumbar facet dimensions and an individual’s height and weight. Facet tropism is a major characteristic of the thoracolumbar spine, the left being longer in the thorax while the right is longer in the lumbar. In general, facet size is age-independent and greater in males compared with females with a significant ethnic component. Facet length is similar for all thoracic vertebrae, whereas it sharply and continuously increases in the lumbar vertebrae. Facet dimension manifests a bipolar distribution along the thoracolumbar vertebrae. Width/length ratio indicates that facets are longer than wider for most verte-brae. The interarticular area manifests a marked inverted trapezoidal shape at T1–T2, a rectangular shape at T3–L3, and an ordinary trapezoidal shape at L4–L5. Conclusions. Facet tropism is a normal characteristic in humans, yet it varies along the thoracolumbar spine.

Lumbar facet orientation in spondylolysis: a skeletal study.

Study Design. Orientation of the lumbar articular facets at the L1–L5 level was measured and analyzed. Objective. To characterize the relationship between lumbar facet orientation and isthmic spondylolysis. Summary of Background Data. Whereas many studies have explored the relationship between facet orientation in the transverse plane and various spinal pathologies, there is insufficient data regarding this relationship and isthmic spondylolysis. Methods. A 3-dimensional digitizer was used to measure the transverse orientation of the lumbar facet joints at the L1–L5 level in 115 male individuals with bilateral isthmic spondylolysis (at L5) and 120 age and sex-matched normal control subjects from the Hamann-Todd Human Osteological Collection (Cleveland Museum of Natural History, Cleveland, OH). Statistical analysis included paired t tests and analysis of variance. Results. In both isthmic spondylolysis and control groups, considerable shifts were noticed from sagittally oriented articular facets at L1 to frontally oriented facets at L5. The change in orientation was significantly greater (up to 13° at L4) in the isthmic spondylolysis group (right inferior facets). Three of the 4 articular facets of L5 (right and left inferior and right superior) were significantly more frontally oriented in isthmic spondylolysis compared to the control group. A greater tendency of asymmetry in facet orientation was noticed in the isthmic spondylolysis group. Conclusion. Individuals with more frontally oriented facets in the lower lumbar vertebrae incorporated with facet tropism are at a greater risk for developing isthmic spondylolysis at L5.

Schmorl’s nodes distribution in the human spine and its possible etiology

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).

Growth and development of female dancers aged 8-16 years.

Little data are available on the growth and development of young female dancers. The objective of this study was to determine whether the body structure and adipose tissue distribution of dancers aged 8–16 years differ from that of non‐dancer girls. Our cross‐sectional study included a group of 1,482 female dancers, aged 8–16 years, and a control group of 226 female non‐dancers of similar age cohorts. Fourteen anthropometric measurements were recorded and 15 indices calculated. In none of the linear anthropometric measures, were significant differences found between the two groups. The only significant difference relates to the extent and distribution of adipose tissue: At age 8, both groups show similar weight while at age 13 non‐dancers are significantly heavier than dancers (48.4 ± 9.8 kg for non‐dancers and 40.6 ± 8.7 kg for dancers). At age 15, weight differences between the two groups decrease to only 2 kg. The differences in weight are also expressed in skinfold thickness and chest circumference. Patterns of adipose tissue distribution differ between the two groups. Mean age at menarche was 13.1 years among dancers and 12.3 years in non‐dancers. In conclusion, musculoskeletal development was found to be very similar in dancers and non‐dancers. The specific body type reported for professional dancers is more likely acquired via “teachers selection” and not training programs. Parents should not dread the possibility that dance training will delay the growth or reduce the height of their daughters. Am. J. Hum. Biol., 2008.

Injury patterns in young, non-professional dancers

Abstract The aim of the present study was to assess the prevalence and types of injuries in 1336 young, non-professional female dancers (age 8–16 years) who participated in a descriptive mixed (cross-sectional/ longitudinal) cohort study. Previous and current injuries were diagnosed and later classified into seven major categories. Our results show that 569 (42.6%) of the dancers examined manifested an injury. Advanced age and increased exposure to dance yielded an equivalent increase in the prevalence of injured girls: from 1 of 10 girls in the 8-year-old age cohort (mean = 1.05 per 1000 h) to 1 of 3 girls in the 14-year-old age cohort (mean = 1.25 per 1000 h). Time elapsing between first and second injuries decreased with age. Among the youngest group of dancers (8–9 years) the most common injury was tendonitis (41%), while in adolescent dancers (14–16 years) knee injuries became the leading cause of complaints (33%). We conclude that young, non-professional dancers are at high risk of injury. Dancers who had been injured in the past were at higher risk for re-injury. Tendonitis in the foot or ankle joint was a common injury among the youngest dancers, while knee injuries were common among adolescent dancers. A routine screening of this dancer population by an expert in dance medicine will reduce the risk for an injury.

Demographical aspects of Schmorl nodes: a skeletal study.

Study Design. A descriptive study of the association between Schmorl nodes (SNs) and gender, ethnic origin, and age in a normal skeletal population. Objectives. To gain reliable data on behavioral patterns of SNs in various human groups shedding light on its etiology. Summary of Background Data. Opinions regarding SNs prevalence in human populations vary greatly (from 5% to 70%). This caveat greatly reduced our ability to recognize the etiology of the phenomenon and understand its clinical significance. Methods. Two hundred forty human skeleton vertebrae (T4–L5) from a normal adult population (divided by gender, ethnicity, and age) were examined for SNs. SNs were defined as depressions with sclerotic margins appearing on the vertebral body surface. Results. One hundred sixteen individuals (48.3%) of the 240 studied manifested SNs along their thoracolumbar spine. SNs are age independent and gender and ethnicity dependent, are significantly more common in males (54.2%) versus females (43%) and more common in European-Americans (60.3%) versus African-Americans (36.7%). Conclusion. SNs are a common phenomenon in the normal adult populations with almost half of the individuals in our sample manifesting at least 1 vertebra with SN. Its demographic characteristics suggest that the phenomenon is not of occupational origin, promoting the notion of genetic background.

Facet joints arthrosis in normal and stenotic lumbar spines.

ABSTRACT: 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 gender.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 gender and its prevalence at different spine levels. Additionally, 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 years) and the second, 150 individuals (mean age 52 ± 19 years) without LSS related symptoms. Both left and right FJ arthrosis for each vertebral level (L3 to S1) were evaluated on CT images (Brilliance 64, Philips Medical System, Cleveland Ohio). Chi-Square, Linear-by-Linear Association and McNemar test were carried out to reveal the correlation between FJ arthrosis and demographic factors (age, gender) and prevalence at different lumbar levels in both stenosis and non-stenosis groups. Additionally, a 2-way ANOVA was used to determine the association between BMI and FJ arthrosis.Results. The rate of FJ arthrosis at L3-4 and L4-5 were significantly higher (P<0.001) in the stenotic group compared to the control. In the control group the prevalence of FJ arthrosis increases cephalo-caudally (L3-L4 = 16%, L4-L5 = 28%, L5-S1 = 55%), whereas in the stenotic group there is a sharp increase from L3-4 (27%) to L4-5 (58%), but not from L4-5 to L5-S1 (55%). No association between FJ arthrosis and gender 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 L3-4. 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 L3-4.Conclusion. FJ arthrosis is an age-dependent and BMI and gender-independent phenomenon. In the general population, the prevalence of FJ arthrosis increases cephalo-caudally with the highest frequency at L5-S1. In the stenotic group, the highest frequency was observed at the two caudal levels; L4-5 and L5-S1. The prevalence of FJ arthrosis was greater for the right side.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.

A morphological adaptation of the thoracic and lumbar vertebrae to lumbar hyperlordosis in young and adult females

The lumbar shape in females is thought to be unique, compensating for lumbar hyperlordosis. Yet, the morphological adaptation of various vertebral parameters in the thoracic and lumbar spine to this unique posture in young and adult females has only been partially addressed in the literature. Our aim was to investigate the gender association to vertebral shape in the thoracic and lumbar spine as a possible adaptation to lumbar hyperlordosis in young and adult females. A three-dimensional digitizer was used to measure the vertebral body sagittal wedging, relative spinous process thickness, and relative interfacet width at the T1–L5 level. Two hundred and forty complete, non-pathological skeletons of adults and 32 skeletons of young individuals were assessed. Three major results were found to be independent of age and ethnicity: (a) VB sagittal wedging in females was significantly less kyphotic than males from T9 to L2 (T11 excluded) with a cumulative mean difference of 8.8°; (b) females had a significantly relatively thinner lumbar spinous processes and (c) females had a relatively wider superior interfacet distance (T9–T10 and L1–L4) than males. We conclude that the combination of less kyphotic VB wedging in the lower thoracic and upper lumbar vertebrae, relatively greater interspinous space and larger interfacet width in the lumbar spine in females are key architectural elements in the lumbar hyperlordosis in females and may compensate for the bipedal obstetric load during pregnancy.

Sacroiliac joint bridging: demographical and anatomical aspects.

Study Design. A descriptive study of the association between sacroiliac joint bridging (SIB) and age, gender, laterality, and ethnic origin in a normal skeletal population. The effectiveness of radiographs in identifying SIB was also evaluated. Objectives. To characterize the phenomenon of SIB demographically and anatomically and to evaluate the validity of diagnosis based on roentgenograms. Summary and Background Data. Although SIB is an important diagnostic parameter in many spinal diseases, the type of association between them has never been established. Furthermore, the extent of SIB in humans and its relationship to demographic parameters await osteological research as radiograph studies hamper the results. Methods. Two thousand eight hundred and forty-five skeleton pelves were examined for SIB. Extent and laterality were recorded. Ten pelves (5 with SIB and 5 without) were X-rayed and the roentgenograms given to radiologists for evaluation. Results. Sacroiliac bridging was present in 12.27% of all males, contrasted with only 1.83% of females (P < 0.001). SIB was independent of ethnic origin (P = 0.0535) but was age-dependent (r = 0.985; P = 0.0001). Bridging was present bilaterally in 38.6% of the individuals and in the superior region in 72.4%. Diffuse bridging (areas 1–6) was present in only 2.3% of the individuals. Radiologic examination was insensitive to diagnosis of SIB. Conclusions. SIB is a common, but predominantly male phenomenon. Its occurrence is age-dependent and ethnicity independent. Bridging occurs mainly on the superior aspect of the sacroiliac joint. The irregular shape and orientation of sacroiliac joints preclude definitely distinguishing normal versus bridged joints from roentgenograms. Our findings also negate the belief that bridging/fusion of the sacroiliac joint represents the most severe form of osteoarthritis and mandate that they be separately recorded and that their significance be determined.