Forward step down test - clinical rating is correlated with joint angles of the pelvis and hip: an observational study.

BACKGROUND: Clinical methods for assessing quality of movement and functional tests are important to clinicians. Typical deviations from normal kinematics during the clinical test of Forward Step Down Test (FSDT) are pelvic tilt and hip adduction which are associated with the risk of knee pain. OBJECTIVES: (1) to examine the correlation between clinical assessment of the FSDT and joint angle measurements of pelvis, hip, knee and ankle joints in males and females; (2) to examine the differences in joint angles between individuals rated as good, fair or poor in a FSDT performance test. METHODS: Ninety-two healthy individuals performing FSDT were video-taped with two-dimensional digital video cameras. The clinical assessment of the FSDT was rated by two experienced physical therapists as good, fair, or poor based on a Crossley et al. (2011) validated scale. Measurements of pelvic drop, hip adduction and knee valgus were taken using Image J software. RESULTS: Out of 177 lower limbs, 74 (37 in each limb) were clinically rated as "good/fair" (41.80%) while 103 (52 in the dominant leg and 51 in the non-dominant leg) were rated as "poor" (58.19%). No significant differences were observed between dominant and non-dominant legs or between males and females in clinical rating of the FSDT. Pelvic drop angle was significantly higher and hip adduction angle was significantly lower for "poor" clinical rating compared to "good/fair" in both dominant and non-dominant legs (p < 0.001) in males and females. Females demonstrated higher pelvic drop, lower hip adduction and higher knee valgus angles compared with males (p < 0.05). CONCLUSIONS: This study showed that the clinical rating of FSDT is correlated with joint angle measurements suggesting that this assessment can be utilized in clinical practice. Individuals with poor quality performance of FSDT showed higher pelvic drop and hip adduction movement. Further studies examining different populations with diverse disorders or pathologies are essential.

On the job training in the dissection room: from physical therapy graduates to junior anatomy instructors.

BACKGROUND:  The training of near-peer (NP) teachers and junior faculty instructors received major attention as a possible solution for the shortage of experienced anatomy instructors in faculties of medicine and health professions. Several studies described the training of NP teachers and junior instructors (≤ 2 years of teaching experience) using various methods. However, few publications include On the Job Training (OJT), which enables reflection and performance evaluation and encourages professionals to cope with their blind spots. Previous publications describing OJT did not include formal observation of the NP teacher or junior instructor. Therefore, this study aimed to present a novel approach to OJT inclusion during prosection laboratories based on the Lewinian experiential model. METHODS:  Eight physical therapy (PT) graduates were recruited as junior anatomy instructors into the prosection laboratories. All participated in a unique training program during two consecutive academic years (2017, 2018) and received OJT during the teaching sessions. Two questionnaires were filled out to evaluate the educational impact of the training program. Eighty-three first-year PT students participated in prosection laboratories in anatomy taught by junior instructors, and filled out a questionnaire evaluating the performance of both junior and senior instructors. In addition, we compared the final grades in anatomy obtained by students taught by senior instructors to the grades of those taught by junior instructors. RESULTS:  Each junior anatomy instructor participated in four OJT sessions. Based on self-reported measures, all professional and didactic aspects of the training program received a median score of 4.5 or higher on a five-point Likert scale. Students obtained similar grades in anatomy when taught by junior instructors compared with senior ones, and were similarly satisfied from the teaching performance of both senior and junior anatomy instructors. CONCLUSIONS:  OJT is applicable in a small-sized PT program facing a shortage of anatomy instructors. Including junior anatomy instructors in prosection laboratories for PT students is a viable solution to the shortage of experienced anatomy instructors. Further study, involving a larger cohort with a longer follow up will strengthen the preliminary results presented here.

New methods for sex estimation using sternum and rib morphology.

Sex estimation of skeletal remains is of great importance in the fields of physical and forensic anthropology. Since skeletons are often incomplete, it is essential to estimate sex from as many skeletal remains as possible. The aim of this study was to establish new methods for estimating sex using the morphology of the sternum and the fifth to ninth ribs. We considered two conditions of skeletal preservation: All skeletal elements measured are available, or only a single element is available. Traditional or virtual measurements were carried out on three samples: (1) A skeletal sample from the Hamann-Todd Human osteological collection, Cleveland Museum of Natural History, USA (N = 413), was used to create prediction equations for sex estimation. (2) A recent, CT-based sample from Israel (N = 33) was used to cross-validate the accuracy of the prediction equations. (3) A skeletal sample from the Anthropological Collection at Tel Aviv University (N = 15) was used to test the validity of the virtual measurements. Reliability and validity analyses were carried out via intraclass correlation coefficient analysis. Prediction equations for sex were created using logistic regression. The measurements were found to be highly reliable and valid. Success rates for sex estimation were high (> 80%) and correspond well between the skeletal and recent samples, especially for the left sixth, left eigth, and left ninth ribs. To conclude, measurements of the sternum and ribs are valuable for estimating sex and can be carried out using either traditional or virtual tools. Of all the skeletal elements examined in this study, the sternum, left sixth, left eighth, and left ninth ribs were found to be the most reliable skeletal elements for estimating the sex of an individual.

Weight Stigmatization among Physical Therapy Students and Registered Physical Therapists.

INTRODUCTION: Weight stigmatization is reflected in anti-fat attitudes and stereotypical perceptions of people who are overweight; it has been demonstrated to be prevalent in many segments of society across multiple countries. Studies examining the prevalence of weight stigmatization use different research tools, which can hinder inter-study comparisons. There is also evidence indicating weight stigmatization among registered physical therapists, although its magnitude differs between studies. Limited information exists regarding the attitudes and beliefs of physical therapy (PT) students toward individuals with obesity. Examining weight stigmatization among PT students is particularly important for developing appropriate educational interventions that may influence the professional lives of future physical therapists. OBJECTIVE: This study aims to characterize and compare the stigmatizing attitudes and beliefs of PT students and certified physical therapists regarding people with obesity in Israel. Its secondary objective is to translate three weight stigmatization questionnaires into Hebrew and determine their psychometric properties. METHODS: A cross-sectional, anonymous, and computerized self-report survey was completed by 285 certified physical therapists (average age 39.6 ± 10.1 years) and 115 PT students (average age 26.4 ± 4.9 years). The study used three validated weight stigma questionnaires employed in earlier studies to determine different aspects of weight stigmatization: the Fat Phobia Scale (short form; FPS), Anti-Fat Attitudes (AFA) questionnaire, and Beliefs about Obese People (BAOP). These questionnaires were translated into Hebrew and their psychometric properties ascertained. RESULTS: Similar to the original English versions, the translated versions of the three questionnaires demonstrated good internal consistency (Cronbach's α values of FPS = 0.77; AFA = 0.75; BOAP = 0.59). The three questionnaires showed a low correlation. No significant difference was noted in the FPS and AFA scores between groups, reflecting that both demonstrated average weight stigmatization (FBS in both groups: average score of 3.6 out of 5; AFA therapists: 3.3 ± 1.2, students: 3.0 ± 1.2 out of 9). However, significant between-group differences were observed for BOAP, which examines beliefs regarding individuals' control over their weight (therapists: 16.4 ± 5.6, students: 18.0 ± 5.7 out of 48; p < 0.01). CONCLUSION: Student and certified physical therapists demonstrate average levels of weight stigmatization, as reflected in the FPS and AFA scores. Nevertheless, compared to certified physical therapists, physical therapist students believe more strongly that obesity cannot be controlled by the individual. The students' beliefs could affect their clinical judgment and behavior as health care professionals in the future. Therefore, anti-fat attitudes and stereotypical perceptions should be addressed and remediated early using educational interventions during the study period.

Sacral orientation and Scheuermann's kyphosis.

To examine whether the association between spinal alignment and sacral anatomical orientation (SAO) can be detected in skeletal populations, by comparing SAO values in individuals with a typical SD to individuals with normal spinal alignment. 2025 skeletons were screened for Scheuermann's disease. Scheuermann's kyphosis was established by the presence of apophyseal abnormalities associated with more than 5° of anterior wedging in each of three adjacent vertebrae. SAO was measured as the angle created between the intersection of a line running parallel to the superior surface of the sacrum and a line running between the anterior superior iliac spine and the anterior-superior edge of the symphysis pubis (PUBIS). SAO was measured on 185 individuals with normal spines and 183 individuals with Scheuermann's kyphosis. Out of 2025 skeletons, 183 (9 %) were diagnosed with Scheuermann's kyphosis. The sacrum was significantly more horizontally oriented in individuals with Scheuermann's kyphosis compared with the control (SAO: 44.44 ± 9.7° vs. 50 ± 9.9°, p < 0.001). Alteration in spinal biomechanics due to a horizontally orientated sacrum may be an important contributing factor for the development of Scheuermann's kyphosis.

Injuries in female dancers aged 8 to 16 years.

CONTEXT: Most studies of injured dancers have been carried out on professional adult dancers; data on young, nonprofessional injured dancers are sparse. OBJECTIVE: To identify the types of injuries sustained by recreational dancers and to examine their association with age, joint range of motion, body structure, age at menarche, presence of anatomic anomalies, and physical burden (i.e., practice hours en pointe). DESIGN: Descriptive epidemiology study. SETTING: The Israel Performing Arts Medicine Center, Tel Aviv. PATIENTS OR OTHER PARTICIPANTS: A total of 569 injured female dancers, aged 8 to 16 years. MAIN OUTCOME MEASURE(S): Dependent variables were 61 types of current injuries that were later classified into 4 major categories: knee injuries, foot and ankle tendinopathy, back injuries, and other injuries. Independent variables were age, joint range of motion, body size and shape, age at menarche, anatomic anomalies, and dance discipline (e.g., hours of practice per week en pointe). RESULTS: At least 1 previous injury had been sustained by 42.4% of the dancers. The most common injuries involved the knee (40.4%), followed by other injuries (23.4%). The relative frequency of back injuries and tendinopathy decreased with age, whereas knee injuries increased. Types of injuries were significantly associated with ankle plantar flexion, hip external rotation, hip abduction, and knee flexion. Multinomial regression analysis revealed only 3 predictive variables (with other as baseline), all for back injury: scoliosis, age, and hip external rotation. CONCLUSIONS: Joint range of motion and scoliosis may signal the potential for future injury. Young dancers (less than 10 years of age) should not be exposed to overload (especially of the back) or extensive stretching exercises.

Morphological characteristics of the young scoliotic dancer.

BACKGROUND: The literature lacks important data about the relationship between scoliosis and growth process, scoliosis and intensive exercise, scoliosis and morphological characteristics, and scoliosis and injuries, among young dancers. OBJECTIVE: The aims of the present study were to determine the extent to which dance experience, body structure, anatomical anomalies and injuries are associated with scoliosis, and to identify variables able to discriminate between scoliotic and non-scoliotic female dancers at time of screening. DESIGN: Cross-sectional cohort study. METHODS: One thousand two hundred and eighty-eight non-professional female dancers, aged 8-16 years, were screened for the current study. We determined their morphometrical profile (height, weight, BMI), dance discipline (as hours of practice per week), manifestation of anatomical anomalies, and existing injuries. All dancers were clinically examined for presence of scoliosis. RESULTS: Three hundred and seven of the 1288 dancers (23.8%) were diagnosed as having scoliosis. Dance experience and body structure were similar for dancers with or without scoliosis. Scoliotic dancers presented a significantly higher prevalence of anatomical anomalies (such as genu varum, and hallux valgus). Back injuries were more common among scoliotic dancers compared to non-scoliotic dancers. CONCLUSION: Screening and identifying the young scoliotic dancers prior to their advancing to higher levels of exercise is recommended. The scoliotic dancers should realize that there might be a connection between the presence of scoliosis and increased incidence of anatomical anomalies and back pain, hence, it should be suggested they seek help with an adequate assessment and exercise rehabilitation program.

Extrinsic and intrinsic risk factors associated with injuries in young dancers aged 8-16 years.

In the present study, we tried to determine the association between joint ranges of motion, anatomical anomalies, body structure, dance discipline, and injuries in young female recreational dancers. A group of 1336 non-professional female dancers (age 8-16 years), were screened. The risk factors considered for injuries were: range of motion, body structure, anatomical anomalies, dance technique, and dance discipline. Sixty-one different types of injuries and symptoms were identified and later classified into four major categories: knee injuries, foot or ankle tendinopathy, back injuries, and non-categorized injuries. We found that 569 (42.6%) out of the 1336 screened dancers, were injured.The following factors were found to be associated with injuries (P < 0.05): (a) range of motion (e.g. dancers with hyper hip abduction are more prone to foot or ankle tendinopathies than dancers with hypo range of motion; (b) anatomical anomalies (scoliotic dancers manifested a higher rate of injuries than non-scoliotic dancers); (c) dance technique (dancers with incorrect technique of rolling-in were found to have more injuries than dancers with correct technique); (d) dance discipline (an association between time of practice en pointe and injury was observed); and (e) early age of onset of menarche decreased risk for an injury. No association between body structure and injury was found. Injuries among recreational dancers should not be overlooked, and therefore precautionary steps should be taken to reduce the risk of injury, such as screening for joint range of motion and anatomical anomalies. Certain dance positions (e.g. en pointe) should be practised only when the dancer has already acquired certain physical skills, and these practices should be time controlled.

Facet joints arthrosis in normal and stenotic lumbar spines.

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.

The epiphyseal ring: a long forgotten anatomical structure with significant physiological function.

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.

Injury patterns in young, non-professional dancers.

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.

Paratenonitis of the foot and ankle in young female dancers.

BACKGROUND: In their pursuit of excellence, dancers continually face the risk of injuries, such as paratenonitis. This attests to the strong need for preventive action, which is possible only if major risk factors are identified. The aim of the present descriptive study was to determine the association between risk factors and paratenonitis in young recreational female dancers. METHODS: One thousand eighty-two non-professional female dancers, aged 8 to 16 years, were screened. The risk factors considered for paratenonitis were: joint range of motion (ROM), body structure, anatomic anomalies, dance technique, and dance discipline. All dancers were clinically examined for current ankle/foot paratenonitis. RESULTS: Ninety-three dancers (8.6%) manifested a paratenonitis at the ankle or foot joints. ROM such as hyper ankle plantarflexion and hyper hip external rotation, false dance technique, and hours of practice per week were found to be associated with increased rate of injury. Regression analysis indicated that dancers with paratenonitis had greater hip external rotation ROM compared to dancers without paratenonitis. No association with injury was found with age of onset of menarche, body structure, and anatomic anomalies such as scoliosis. CONCLUSION: Precautionary steps, such as screening for joint ROM and dance technique, may reduce the risk of dance injury. Furthermore, our results led to a very significant justification of the dance maxim ``don't force your natural joint ROM and especially your `turnout' position,'' as it could increase your chance to develop paratenonitis.

A new look at the geometry of the lumbar spine.

STUDY DESIGN: A retrospective cohort study of the relationship between the structures that form the lumbar spine in humans. OBJECTIVE: To investigate the relationship between the segmental wedging of the vertebral bodies and that of the intervertebral discs, and between the overall lordosis angle and each of the 5 lumbar segments. SUMMARY OF BACKGROUND DATA: Little attention has been paid to the internal relationship between the structures that form the lumbar spine. Understanding these relationships is instrumental to our ability to restore and rehabilitate the lordotic curvature. METHODS: Lateral radiographs of 101 adult lumbar spines were examined in patients at spinal clinics. The patients had no history of spinal surgery and no radiographic abnormality. The radiologic parameters are the lordosis angle (LA), the body wedge angle (B), the total segmental angle (S), and the intervertebral disc angle (D). Measurements B, S, and D were taken for each of the 5 lumbar segments. Measurements B and D were used to calculate ΣB, the sum of the B, and ΣD, the sum of the D. RESULTS: The LA correlates with the sum of the vertebral body angles and with the sum of the intervertebral disc angles. Vertebral body wedging is negatively correlated with intervertebral disc wedging. The middle 3 lumbar segments are moderately-to-poorly correlated, among themselves and with the LA, while the upper and lower lumbar segments are poorly correlated with the LA and not correlated with any lumbar segment. CONCLUSION: Three parts of the lumbar lordosis were identified: the upper part, formed by the first lumbar segment; the middle part, formed by the middle 3 segments; and the lower part, formed by the fifth lumbar segment. The statistical study shows an inverse relationship between vertebral body and intervertebral disc wedging.

Morphology and function of the lumbar spine of the Kebara 2 Neandertal.

The morphology of the lumbar spine is crucial for upright posture and bipedal walking in hominids. The excellent preservation of the lumbar spine of Kebara 2 provides us a rare opportunity to observe a complete spine and explore its functionally relevant morphology. The lumbar spine of Kebara 2 is analyzed and compared with the lumbar spines of modern humans and late Pleistocene hominids. Although no size differences between the vertebral bodies and pedicles of Kebara 2 and modern humans are found, significant differences in the size and orientation of the transverse processes (L(1)-L(4)), and the laminae (L(5), S(1)) are demonstrated. The similarity in the size of the vertebral bodies and pedicles of Kebara 2 and modern humans suggests similarity in axial load transmission along the lumbar spine. The laterally projected (L(2)-L(4)) and the cranially oriented (L(1), L(3)) transverse processes of Kebara 2 show an advantage for lateral flexion of the lumbar spine compared with modern humans. The characteristic morphology of the lumbar spine of Kebara 2 might be related to the wide span of its pelvic bones.

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 degrees ; (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.

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).

Sacral orientation and spondylolysis.

STUDY DESIGN: A descriptive study (based on skeletal material) was designed to measure sacral anatomic orientation (SAO) in individuals with and without spondylolysis. OBJECTIVE: To test whether a relationship between SAO and spondylolysis exists. SUMMARY OF BACKGROUND DATA: Spondylolysis is a stress fracture in the pars interarticularis (mainly of L5). The natural history of the phenomenon has been debated for years with opinions divided, i.e., is it a developmental condition or a stress fracture phenomenon. There is some evidence to suggest that sacral orientation can be a "key player" in revealing the etiology of spondylolysis. METHODS: The pelvis was anatomically reconstructed and SAO was measured as the angle created between the intersection of a line running parallel to the superior surface of the sacrum and a line running between the anterior superior iliac spine (ASIS) and the anterior-superior edge of the symphysis pubis (PUBIS).SAO was measured in 99 adult males with spondylolysis and 125 adult males without spondylolysis. The difference between the groups was tested using an unpaired t test. RESULTS: Spondylolysis prevalence is significantly higher in African-Americans compared to European-Americans: 5.4% versus 2.04% in males (P < 0.001) and 2.31% versus 0.4%, P < 0.001 in females. SAO was significantly lower in the spondylolytic group (44.07 degrees +/- 11.46 degrees) compared to the control group (51.07 degrees +/- 8.46 degrees, P < 0.001). CONCLUSION: A more horizontally oriented sacrum leads to direct impingement on L5 pars interarticularis by both L4 inferior articular facet superiorly and S1 superior articular facet inferiorly. Repetitive stress due to standing (daily activities) or sitting increases the "pincer effect" on this area, and eventually may lead to incomplete synostosis of the neural arch.

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 asymmetry in normal vertebral growth: characterization and etiologic theory of scoliosis.

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.

Polyphenol oxidase can cross thylakoids by both the Tat and the Sec-dependent pathways: a putative role for two stromal processing sites.

Polyphenol oxidase (PPO; EC 1.10.3.2 or EC 1.14.18.1), a thylakoid-lumen protein encoded by a nuclear gene, plays a role in the defense of plants against both herbivores and pathogens. Although previously reported to be a Tat (twin-arginine-dependent translocation) protein, the import of PPO by isolated chloroplasts was inhibited by azide, a diagnostic inhibitor of the Sec-dependent pathway. Import of PPO inhibited thylakoid translocation of a Tat protein and did not affect translocation of Sec-dependent proteins. In contrast, a pre-accumulated iPPO competed with Sec-dependent but not with Tat proteins. A previously reported second processing step in the stroma removes a twin-Arg that is part of a 'Sec-avoidance' motif in the thylakoid targeting domain of PPO. When the second processing site was mutated, the import of the resulting precursor showed Sec-dependent characteristics. The PPO transit peptide could drive thylakoid translocation of a Tat protein in the dark. Azide inhibited the secretion of a PPO intermediate that lacks a twin-Arg to the periplasm of Escherichia coli, but had no effect on the export of the intermediate containing the twin-Arg. PPO is synthesized in plants in response to wound and pathogen-related signals and it is possible that when the Tat pathway is unable to translocate adequate amounts of newly synthesized PPO, translocation is diverted to the Sec-dependent pathway by processing the intermediate at the second site and removing the twin-Arg.