Comparative anatomy and ontogeny of appendicular skeleton of Pseudopus apodus (Pallas, 1775) (Anguimorpha, Anguidae) and a pattern of hindlimb loss in Anguinae.

We present a detailed anatomy of the pectoral girdles, pelvic girdles, and hindlimbs of adult and juvenile specimens of Pseudopus apodus (Pallas, 1775). We compared the individual bones of the appendicular skeleton of P. apodus with those of Anguis fragilis and species of Ophisaurus living in North America, North Africa, and Southeast Asia. We found no anatomical features in P. apodus in common with the species of Ophisaurus living in only North America, North Africa, and Southeast Asia. Additionally, we present the prehatching ontogeny of the pelvic girdle of P. apodus and A. fragilis and the prehatching ontogeny of the hindlimb of P. apodus. In the ontogeny of the pelvic girdle of P. apodus, it is possible to distinguish the ossification centers of ilium, ischium, and pubis. In contrast, in the ontogeny of A. fragilis, no ossification centers of ilium, ischium, and pubis are present, and no hindlimb element was detected. In Stage 1 of ontogeny in Pseudopus, the femur and tibia are present; in Stage 2, the nodule representing the fibula appears; and in Stage 3, in addition to the femur, tibia, and fibula, four tarsal elements are present. This anatomical condition corresponds to the anatomical composition of the hindlimb of the adult O. koellikeri. In Stage 4, the involution of all tarsal elements and fibula begins, and in the last two prehatching stages, only femur and tibia remain; this condition is present not only in the adults of Pseudopus, but also in those of several other species of Ophisaurus.

Comparison of Ischial Containment and Subischial Sockets on Comfort, Function, Quality of Life, and Satisfaction With Device in Persons With Unilateral Transfemoral Amputation: A Randomized Crossover Trial.

OBJECTIVE: To compare comfort and functional performance of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket with the ischial containment (IC) socket in persons with unilateral transfemoral amputation. DESIGN: Randomized crossover trial with two 7-week periods. SETTING: Private prosthetic clinics and university research laboratory. PARTICIPANTS: A total of 30 enrolled (N=30); 25 participants completed the study with full (n=18) or partial data (n=7). INTERVENTIONS: Two custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery. MAIN OUTCOME MEASURES: The primary outcome was change in Socket Comfort Score (SCS) at 7 weeks. Secondary outcomes at 7 weeks included the Orthotic and Prosthetic Users' Survey (OPUS) to assess lower extremity functional status, health-related quality of life, and satisfaction with device, as well as the 5-Times Rapid Sit-to-Stand Test, Four Square Step Test, and T-Test of Agility to assess functional performance. RESULTS: At 7 weeks, the mean SCS for IC (7.0±1.7) and NU-FlexSIV (8.4±1.1) Sockets were significantly different (P<.001; 95% confidence interval, 0.8-2.3). Results from a linear mixed-effects model, accounting for data from all time points, indicated that the SCS was 1.7 (SE=0.45) points higher for the NU-FlexSIV Socket (P<.001). For the secondary outcomes, only OPUS satisfaction with device was significantly better in the NU-FlexSIV Socket after accounting for all data points. CONCLUSIONS: The results suggest that after 7 weeks' accommodation, the NU-FlexSIV Socket was more comfortable and led to greater satisfaction with device than the IC socket in persons with unilateral transfemoral amputation and K3/K4 mobility. Other patient-reported outcomes and function were no different between sockets.

The infragluteal fold: An appraisal by MRI combined with an anatomic study.

PURPOSE: The gluteal region is a key element of beauty balance and sexual appearance. However, there is no clear anatomical description of the infragluteal fold, nor any classification exists allowing standardizing treatment of this area in case of jeopardisation. The purpose of this study was to perform an anatomical description of the infragluteal fold (IGF) matching radiological and anatomical findings in describing specifically raise of the fibrous component at the bone level. METHODS: Six volunteers (three males and three females) underwent an MRI scan (Siemens Aera® 1.5 T) of the pelvic region. T1 Vibe Morpho T2, Sag Space 3D, and Millimetric slices were performed in order to obtain a more detailed selection of the gluteal landmark. Trabecular connective tissue of the region was analyzed using Horos® ROI (region of interest) segmentation function. Four fresh cadavers (two males, two females, accounting for 8 hemipelvis) were dissected in order to compare the radiological findings. RESULTS: The infragluteal fold is a connectival fibrous band extending from the ramus of the ischium (but not involving the ischial tuberosity, for a length of 21 mm ± 2 and 21 mm ± 3), the apex of the sacrum (for a length of 13 ± 2 and 11 mm ± 2), and the coccyx (for a length of 19 mm ± 2 and 20 mm ± 2, all measures referring to volunteers and cadavers, respectively) reaching superficially the dermis of the medial one-third of the cutaneous fold. No significant difference was found between volunteer and cadaver group in MRI measurement of bony origins, or between MRI and cadaveric dissection measurements. CONCLUSION: Knowledge of this structure will define novel surgical techniques in infragluteal fold restoration.

An evaluation of statistical models for age estimation and the assessment of the 18-year threshold using conventional pelvic radiographs.

The developmental patterns of the pelvic epiphyses are one of the anatomical markers used in the assessment of skeletal age and the legally relevant age threshold. In this study, four regression models and five classification models were developed for forensic age estimation and the determination of the 18-year threshold, respectively. A total of 2137 conventional pelvic radiographs (1215 males and 922 females) aged 10.00-25.99 years were analyzed, and the ossification and fusion of the iliac crest and ischial tuberosity epiphyses were scored separately. The epiphyses on both sides were used as inputs for all models. The accuracy of the regression models was compared using the mean absolute error (MAE) and root mean square error. The percentages of correct classifications were evaluated for the determination of the 18-year threshold. Support vector regression (SVR) and gradient boosting regression (GBR) showed higher accuracy for age estimation in both sexes. The lowest MAE was 1.38 years in males when using SVR and 1.16 years in females when using GBR. In the demarcation of minors and adults, the percentage of correct classification was over 92%, and the area under the receiver operating characteristic curves was over 0.91 in all models, except the Bernoulli naive Bayes classifier. This study demonstrated that the present models may be helpful for age estimation and the determination of the 18-year threshold. However, owing to the high effective dose of ionizing radiation used during conventional radiography of the pelvis, it is expected that these models will be tested with pelvic MRI for age estimation.

Assessing the fusion of the ischiopubic synchondrosis using predictive modeling.

Flaring of the ischiopubic synchondrosis at the time of fusion is a common clinical observation in pediatrics and represents a normal physiological process in skeletal maturation. When presenting unilaterally, this flaring can mimic a range of serious pathological conditions such as osteomyelitis, osteal tumors, and traumatic injury. An improved understanding of ischiopubic synchondrosis fusion is therefore critical to avoid potential misdiagnosis. Retrospective multi-slice computed tomography pelvic scans of Australian individuals aged neonate to 24 years (n = 184) were assessed using a novel five stage morphological classification system of the maturation and fusion of the ischiopubic synchondrosis. Maturation scoring was conducted using both multiplanar formatting views and volume-rendered reconstructions in OsiriX™. Maturational stage was strongly related to age (P < 0.001) with fusion of the ischiopubic synchondrosis observed between the ages of 4 and 9 years in females and 7 and 13 years for males. The highest probability of fusion in our Queensland Australian population based on multinomial regression predictive modeling was between 7 and 10 years of age. We documented three variants of fusion: pubic and ischial outgrowths, appearance of a secondary ossification center, and a fusiform-shaped enlargement. This study provides the first predictive modeling of the timing of fusion of the ischiopubic synchondrosis using a reliable morphological classification system. The significant variation in timing and progression of fusion of the ischiopubic synchondrosis reported in this study, will aid in minimizing misdiagnosis and unnecessary treatment in children presenting with asymmetrical or delayed ischiopubic synchondrosis anomalies. Clin. Anat. 32:851-859, 2019. © 2019 Wiley Periodicals, Inc.

The birth canal: correlation between the pubic arch angle, the interspinous diameter, and the obstetrical conjugate: a computed tomography biometric study in reproductive age women.

Background: Assessment of pelvic configuration is an important factor in the prediction of a successful vaginal birth. However, manual evaluation of the pelvis is practically a vanishing art, and imaging techniques are not available as a real-time bed-side tool. Unlike the obstetrical conjugate diameter (OC) and inter spinous diameter (ISD), the pubic arch angle (PAA) can be easily measured by transperineal ultrasound. Objectives: Three-dimensional computed tomography bone reconstructions were used to measure the three main birth canal diameters, evaluate the correlation between them, and establish the normal reference range for the inlet, mid-, and pelvic outlet. Study design: Measurements of the PAA, obstetric conjugate (OC), and ISD were performed offline using three-dimensional post processing reconstruction in bone algorithm application of the pelvis on examinations performed for suspected renal colic in nonpregnant reproductive age woman. The mean of two measurements was used for statistical analysis which included reproducibility of measurements, regression curve estimation between PAA, OC, and ISD, and calculation of the respective reference range centiles for each PAA degree. Results: Two hundred ninety-eight women comprised the study group. The mean ± SD of the PAA, ISD, and OC were 104.9° (±7.4), 103.8 mm (±7.3), and 129.9 mm (±8.3), respectively. The intra- and interobserver agreement defined by the intraclass correlation coefficient (ICC) was excellent for all parameters (range 0.905-0.993). A significant positive correlation was found between PAA and ISD and between PAA and OCD (Pearson's correlation = 0.373 (p < .001), and 0.163 (p = .022), respectively). The best regression formula was found with quadratic regression for inter spinous diameter (ISD): 34.122778 + (0.962182*PAA - 0.002830*PAA2), and linear regression for obstetric conjugate (OC): 110.638397 + 0.183156*PAA. Modeled mean, SD, and reference centiles of the ISD and OCD were calculated using the above regression models as function of the PAA. Conclusions: We report significant correlation between the three pelvic landmarks with greatest impact on the prediction of a successful vaginal delivery: the PAA which is easily measured sonographically and the ISD and OC which are not measurable by ultrasound. This correlation may serve as a basis for future studies to assess its utility and prognostic value for a safe vaginal delivery.

The effect of saddle nose width and cutout on saddle pressure distribution and perceived discomfort in women during ergometer cycling.

The objectives were 1) to design and produce two novel unpadded bicycle saddles with a wide/medium width and partial nose cutout; 2) to investigate the responses on pressure distribution and perceived discomfort in female cyclists. For comparison, a standard saddle was also tested. Nineteen female cyclists pedaled on an ergometer cycle for 20 min with each saddle in a counterbalanced order. A pressure mat measured saddle interface pressure. Discomfort ratings were collected using a visual analogue scale. Total mean saddle pressure remained similar across saddles. The wide saddle increased anterior and decreased posterior mean saddle pressure as compared with the standard (p < .002) and the medium saddle (p < .001). Significantly increased ischial tuberosity discomfort was found for the novel saddles (p < .001), while crotch discomfort was not significantly different between saddles. The medium width saddle appeared to be the best compromise since increased crotch discomfort was avoided and saddle pressures were redistributed. Such design may be suggested as an alternative to traditional saddles for women reporting discomfort in the perineal region.

Specific-age group sex estimation of infants through geometric morphometrics analysis of pubis and ischium.

Sex determination of unknown individuals is one of the primary goals of Physical and Forensic Anthropology. The adult skeleton can be sexed using both morphological and metric traits on a large number of bones. The human pelvis is often used as an important element of adult sex determination. However, studies carried out about the pelvic bone in subadult individuals present several limitations due the absence of sexually dimorphic characteristics. In this study, we analyse the sexual dimorphism of the immature pubis and ischium bones, attending to their shape (Procrustes residuals) and size (centroid size), using an identified sample of subadult individuals composed of 58 individuals for the pubis and 83 for the ischium, aged between birth and 1year of life, from the Granada osteological collection of identified infants (Granada, Spain). Geometric morphometric methods and discriminant analysis were applied to this study. The results of intra- and inter-observer error showed good and excellent agreement in the location of coordinates of landmarks and semilandmarks, respectively. Principal component analysis performed on shape and size variables showed superposition of the two sexes, suggesting a low degree of sexual dimorphism. Canonical variable analysis did not show significant changes between the male and female shapes. As a consequence, discriminant analysis with leave-one-out cross validation provided low classification accuracy. The results suggested a low degree of sexual dimorphism supported by significant sexual dimorphism in the subadult sample and poor cross-validated classification accuracy. The inclusion of centroid size as a discriminant variable does not imply a significant improvement in the results of the analysis. The similarities found between the sexes prevent consideration of pubic and ischial morphology as a sex estimator in early stages of development. The authors suggest extending this study by analysing the different trajectories of shape and size in later ontogeny between males and females.

Investigation of the ischioanal fossa: Application to abscess spread.

The location of perianal abscesses and the course of the fistula follow certain patterns, especially in the relationship between external and internal openings. However, it is still not clear how the contents of the ischioanal fossa, especially the fibrous network of fat tissue, affect the route for such diseases. Ten male adult cadavers were selected for the study. Seven horizontal transverse section planes from 1 cm above the pubic symphysis to the inferior border of the lesser trochanter of the femur were recorded after P45 sheet plastination. We observed characteristics of fiber distribution in the ischioanal fossa and its relationship with surrounding structures in every plane. There was a dense strip-type fiber connecting with junction fascia between the obturator internus and gluteus maximus muscles. Close to the levator ani, obturator internus, and gluteus maximus, the fibers were very dense and continuous with the fascia on the surfaces of these three muscles. The function of the fibrous network was considered to be not only the support of fat tissue in the fossa but also cushioning during physiological actions such as defecation. We hope that these morphological results could help to elucidate the passage of fistulae and the locations susceptible to perianal abscesses. Clin. Anat. 30:1029-1033, 2017. © 2017 Wiley Periodicals, Inc.

Ischial Form as an Indicator of Bipedal Kinematics in Early Hominins: A Test Using Extant Anthropoids.

Human ischia contrast with those of great apes in being craniocaudally short and dorsally projecting. This configuration is thought to facilitate greater hip extension in humans during bipedal locomotion. This link has been used to infer kinematics in early hominins, but the consequences of variation in ischial configuration for gait remain uncertain. Kinematic data for a limited sample of extant nonhuman primates demonstrate that there is variation in hip extension in these taxa during bipedal behaviors-specifically, Hylobates and Ateles are capable of greater extension than Pan and Macaca. In this study, we tested the hypothesis that ischial length and orientation are functionally linked with hip extension during bipedalism among these taxa. As expected, humans have the shortest ischia, followed by gibbons, spider monkeys, chimpanzees, and macaques. Our predictions for ischial orientation are not supported, however: macaques, gibbons, and spider monkeys do not vary in this trait, and they have ischia that are less dorsally angled than that of the chimpanzee. The results for ischium length provide limited support for the idea that the early hominin Ardipithecus ramidus, with its long, caudally oriented ischium was not capable of humanlike extended-hip bipedalism, and that the ischial shortening observed in post-Ardipithecus hominins reflects a shift toward a more humanlike gait. In contrast, while our results do not necessarily refute a link between ischial orientation and hip extension in hominins, they do not provide comparative support, making changes in ischial orientation in this part of the fossil record more difficult to interpret. Anat Rec, 300:845-858, 2017. © 2017 Wiley Periodicals, Inc.

Proximity of uterosacral ligament suspension sutures and S3 sacral nerve to pelvic landmarks.

INTRODUCTION AND HYPOTHESIS: To describe the relationships between pelvic bony landmarks to points along the third sacral nerve and to uterosacral ligament suspension sutures. METHODS: Three transvaginal uterosacral ligament suspension sutures were placed bilaterally in unembalmed female human cadavers. The third sacral nerve was marked at the foramen (S3a) and at two additional points at 1-cm intervals along its course caudally (S3b, S3c). Three bony pelvic landmarks were identified and marked, including the ischial spine, pubic symphysis, and coccyx. Distances from each landmark to each suture and nerve point were measured. The distance from each landmark to each S3 nerve point was extended radially, encompassing an arbitrary zone in which sutures may be placed and thus where nerve injury may occur. Zones of potential nerve injury included: zone A (closest to the sacral nerve root), zone B, and zone C (closest to the landmark). Descriptive statistics were used and comparisons were made using Student's t test and ANOVA. RESULTS: Ten cadaver specimens were dissected. For the ischial spine, the distances to points S3a, S3b, and S3c were 6.3, 5.4, and 4.6 cm respectively. Approximately two thirds of the sutures were noted beyond zone C, indicating a potentially increased risk of nerve injury with suture placement in zones farthest from the ischial spine given their proximity to the sacral nerve. CONCLUSIONS: Using the ischial spine as a landmark, increased sacral nerve injury could result from suture placement beyond the mean distance of 4.6 cm from the ischial spine. The use of bony landmarks in avoiding sacral nerve injury may be as important as suture depth and angle of suture placement.

Virtual reconstruction of the Australopithecus africanus pelvis Sts 65 with implications for obstetrics and locomotion.

Characterizing australopith pelvic morphology has been difficult in part because of limited fossilized pelvic material. Here, we reassess the morphology of an under-studied adult right ilium and pubis (Sts 65) from Member 4 of Sterkfontein, South Africa, and provide a hypothetical digital reconstruction of its overall pelvic morphology. The small size of the pelvis, presence of a preauricular sulcus, and shape of the sciatic notch allow us to agree with past interpretations that Sts 65 likely belonged to a female. The morphology of the iliac pillar, while not as substantial as in Homo, is more robust than in A.L. 288-1 and Sts 14. We created a reconstruction of the pelvis by digitally articulating the Sts 65 right ilium and a mirrored copy of the left ilium with the Sts 14 sacrum in Autodesk Maya. Points along the arcuate line were used to orient the ilia to the sacrum. This reconstruction of the Sts 65 pelvis looks much like a "classic" australopith pelvis, with laterally flared ilia and an inferiorly deflected pubis. An analysis of the obstetric dimensions from our reconstruction shows similarity to other australopiths, a likely transverse or oblique entrance of the neonatal cranium into the pelvic inlet, and a cephalopelvic ratio similar to that found in humans today.

Computed tomographic study of anatomical relationship between pubic symphysis and ischial spines to improve interpretation of intrapartum translabial ultrasound.

OBJECTIVE: To analyze the anatomical relationship between the pubic symphysis and the ischial spines to determine reliable landmarks for the assessment of fetal head descent by intrapartum translabial ultrasound (ITU). METHODS: All computed tomography (CT) scans performed for breech presentation and for twin delivery between 2006 and 2014 in a tertiary university hospital were obtained for measurement and analysis by two operators. The symphysis-left ischial spine angle (SIA) and the symphysis-left ischial spine distance (SID) were measured on three-dimensional reconstructions from the CT volume dataset. We calculated intra- and interobserver agreements for SIA and SID with 95% prediction intervals, created Bland-Altman plots with 95% limits of agreement and estimated the intraclass correlation coefficient (ICC). A sagittal plane projection from the SIA enabled calculation of a sagittal angle, corresponding to the angle of progression (AoP) on ITU. RESULTS: SIA and SID were obtained from CT images from 458 women. Reproducibility was good for both SIA (intraobserver ICC, 0.94 (95% CI, 0.88-0.97) and interobserver ICC, 0.81 (95% CI, 0.66-0.92)) and SID (intraobserver ICC, 0.92 (95% CI, 0.82-0.97) and interobserver ICC, 0.83 (95% CI, 0.73-0.92)). The median SIA was 106° (interquartile range (IQR), 105-109°) and median SID was 26.1 (IQR, 23.4-29.5) mm. SIA and SID were not correlated with pelvic diameter or height. The 50th percentile of AoP was 110°. CONCLUSION: Knowledge of the anatomical relationship between the pubic symphysis and ischial spines makes it possible to establish a sonographic method for assesssing fetal head descent by taking into account the level of the ischial spines. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

[Study on morphological characteristics of uterosacral and cardinal ligament in patients with severe pelvic organ prolapse based on MRI].

OBJECTIVE: To evaluate morphological structure of uterosacral ligament (USL) and cardinal ligament (CL) in patients with severe pelvic organ prolapse (POP) by MRI technology, and to analysis and discuss its clinical significance. METHODS: From November 2013 to February 2014 in Peking University People's Hospital, 26 elderly patients with III-IV degree of POP were selected as the POP group and 18 healthy elderly volunteers were selected as the control group during the same period. Pelvic MRI examination were performed in the two groups. The morphological characteristics of left and right side of the uterosacral-cardinal ligament on MRI and the attachment site of the starting and ending points between two group were described and compared. RESULTS: In POP group, 25 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [58% (15/26)] or coccygeal muscle [38% (10/26)], ending point were located in the cervix and vagina [58% (15/26)] or cervix [38% (10/26)]; 24 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex [31% (8/26)] or coccygeal muscle [62% (16/26)], 26 cases of right USL ending point were located in the cervix and vagina [62% (16/26)] or cervix [38% (10/26)]; the left and right CL in the POP group and the control group were both from the sacroiliac joint at the top of the greater sciatic foramen from the ipsilateral pelvic side wall; 1 case (4%, 1/26) of left CL in the POP group completely connected to the bladder, 10 cases (38%, 10/26) partly connected to the bladder; 14 cases (54%, 14/26) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. In the control group, 17 cases of left USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (7/18), ending point were located in the cervix and vagina (12/18) or cervix (6/18); 18 cases of right USL starting point were located in the sacrospinous ligament/coccygeal muscle complex (10/18) or coccygeal muscle (8/18), ending point were located in the cervix and vagina (13/18) or cervix (5/18); 8 cases (8/18) of left CL partly connected to the bladder; 15 cases (15/18) of right CL partly connected to the bladder, the rest ending points of left and right CL were located in cervix and (or) vagina. There was no significant difference between the two groups on the starting and ending points (P > 0.05). CONCLUSIONS: The observation of MRI could be consistent with the clinical anatomy on the starting and ending points, direction of travel in the uterosacral-cardinal ligament. The starting and ending points of the left and right side USL and the ending points of the left and right side CL are not completely symmetrical, the variation degree is large, some CL could be completely or partly inserted to the bladder.

A New Leptoceratopsid (Ornithischia, Ceratopsia) with a Unique Ischium from the Upper Cretaceous of Shandong Province, China.

The partial skeleton of a leptoceratopsid dinosaur, Ischioceratops zhuchengensis gen. et sp. nov., was excavated from the bone-beds of the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. This fossil represents the second leptoceratopsid dinosaur specimen recovered from the Kugou locality, a highly productive site in Zhucheng. The ischium of the new taxon is morphologically unique among known Dinosauria, flaring gradually to form an obturator process in its middle portion and resembling the shaft of a recurve bow. An elliptical fenestra perforates the obturator process, and the distal end of the shaft forms an axehead-shaped expansion. The discovery of Ischioceratops increases the known taxonomic diversity and morphological disparity of the Leptoceratopsidae.

Anatomic Description of the Origin of the Proximal Hamstring.

PURPOSE: To define the topographic anatomy of the footprint of the hamstrings origin on the ischium. METHODS: Dissection of the hamstrings origin in 6 cadaveric pelvises was performed. The hamstrings origin was isolated with sharp dissection, and it was noted whether the semimembranosus had a separate attachment or whether there was one confluent tendon attached at the footprint. The common hamstrings tendon was then sharply dissected from the ischium, and the footprint was outlined with surgical marker followed by radiopaque paint. Paint was prepared by mixing 0.25 g Daler-Rowney acrylic artists ink scarlet no. 567 (Daler-Rowney, Bracknell, England) per gram of EZ-HD 98% v/w barium sulfate (E-Z-EM Inc, Lake Success, NY). The paint was then applied to the area of the footprint, and the specimen underwent a 0.5-mm-slice computed tomographic (CT) scan of the pelvis with 3-dimensional (3D) reconstructions. Vitrea (Vital Images, Minnetonka, MN) software was used to determine the surface area of the ligament footprint as well as the distance from the ischial tuberosity to the center of the footprint. The thickness of the bone underlying the footprint was measured. Data are presented as means ± standard error. RESULTS: Five of 6 specimens had a common hamstrings tendon, whereas one had a separate attachment for the semimembranosus. The semimembranosus joined the common hamstrings tendon 2.33 ± 0.61 cm distal to the footprint. The average surface area of the hamstrings footprint measured 10.19 ± 0.75 cm(2). The distance from the tip of the ischial tuberosity to the center of the hamstrings footprint measured 3.73 ± 0.22 cm. The average thickness of the bone deep to the footprint was 3.77 ± 0.9 cm. CONCLUSIONS: This study provides a topographic description of the origin of the hamstrings footprint and may assist surgeons in performing anatomic reattachment of this tendon. CLINICAL RELEVANCE: Our data will assist surgeons in performing anatomic repair of proximal hamstrings avulsions.

Gross anatomical and dimensional characteristics of the proximal hamstring origin.

PURPOSE: The current study was undertaken to better define the gross anatomical and dimensional characteristics of the proximal hamstring origin. METHODS: Twelve paired whole-lower extremities from six embalmed cadavers were dissected. The gross anatomy of the proximal hamstrings was studied. With the tendons attached to the ischial tuberosity, the width and thickness of each tendon was measured 1 cm distally to their origin, and the distance from the most proximal border of the common origin of the semitendinosus (ST) and long head of the biceps (LB) to their distal junction was assessed. After removal of the hamstring group, the shape, orientation, and dimension of the tendon footprints were determined. RESULTS: One cadaver demonstrated unique anatomy, which was considered as an anatomic variant and was therefore excluded from the study group. The ST and LB had a common origin on the posterolateral aspect of the ischial tuberosity (ST/LB), whereas the semimembranosus (SM) had a separated origin at the anterolateral aspect. The mean distance from the most proximal border of the ST/LB origin to the distal junction was 10.0 ± 1.3 cm. The shape of both footprints was longitudinal-oval, with the longitudinal axes of the SM and ST/LB footprints parallel aligned. Mean tendon width was 3.4 ± 0.5 cm for the common ST/LB complex and 4.2 ± 0.9 cm for the SM (p = 0.009). The corresponding values for tendon thickness were 1.0 ± 0.3 cm (ST/LB) and 0.8 ± 0.2 cm (SM), respectively (n.s.). Mean footprint length was 3.9 ± 0.4 cm for ST/LB and 4.5 ± 0.5 cm for SM (p = 0.002). The corresponding values for footprint height were 1.4 ± 0.5 cm (ST/LB) and 1.2 ± 0.3 cm (SM), respectively (n.s.). CONCLUSION: The ST and LB had a common origin, whereas the SM originated separately. The site of origin of both tendons was the lateral aspect of the ischial tuberosity, with the SM footprint lying directly anterior to the footprint of the ST/LB complex. The footprint of the SM was significantly wider than the footprint of the ST/LB. The reported gross anatomic findings and dimensions may aid surgeons in anchor placement at the anatomical attachment site, thereby facilitating anatomic hamstring repair. In addition, the provided data may improve diagnosis and conservative treatment of proximal hamstring tendinopathy, since detailed knowledge about the normal anatomy is crucial for recognizing tendon abnormalities and for several conservative treatment modalities such as shockwave application or ultrasound-guided injections.

A qualitative and quantitative analysis of the attachment sites of the proximal hamstrings.

PURPOSE: Proximal hamstring tears represent a challenge. Surgical repair of such tears has been reported utilizing both open and endoscopic techniques. It was hypothesized that the proximal attachments of the hamstring muscle group could be reproducibly and consistently measured from pertinent bony anatomical reference landmarks. METHODS: Fourteen fresh-frozen, human cadaveric specimens were dissected, and measurements were taken regarding the proximal attachments of the hamstring muscle group in reference to bony landmarks. A highly precise coordinate measuring device was used for three-dimensional measurements of tendon footprints and bony landmarks, and relevant distances between structures were calculated. RESULTS: The semitendinosus and long head of the biceps femoris shared a proximal origin (conjoined tendon), having an oval footprint with an average area of 567.0 mm(2) [95 % CI 481.0-652.9]. The semimembranosus (SM) footprint was crescent-shaped and located anterolateral to the conjoined tendon, with an average area of 412.4 mm(2) [95 % CI 371.0-453.8]. The SM footprint had an accessory tendinous extension that extended anteromedially forming a distinct footprint. A consistent bony landmark was found at the medial ischial margin, 14.6 mm [95 % CI 12.7-16.5] from the centre of the conjoined tendon footprint, which coincided with the distal insertion of the sacrotuberous ligament. CONCLUSION: The conjoined tendon was the largest attachment of the proximal hamstring group. Two other distinct attachment footprints were identified as the SM footprint and the accessory tendinous extension. The sacrotuberous ligament insertion served as a bony landmark. The anatomical data established in this study may aid in better restoring the anatomy during repair of proximal hamstring tears.

A new basal ankylosaurid (Dinosauria: Ornithischia) from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China.

A new ankylosaurid, Chuanqilong chaoyangensis gen. et sp. nov., is described here based on a nearly complete skeleton from the Lower Cretaceous Jiufotang Formation of Baishizui Village, Lingyuan City, Liaoning Province, China. Chuanqilong chaoyangensis can be diagnosed on the basis of two autapomorphies (glenoid fossa for quadrate at same level as the dentary tooth row; distally tapering ischium with constricted midshaft) and also a unique combination of character states (slender, wedge-like lacrimal; long retroarticular process; humerus with strongly expanded proximal end; ratio of humerus to femur length  = 0.88). Although a phylogenetic analysis places Chuanqilong chaoyangensis as the sister taxon of the sympatric Liaoningosaurus near the base of the Ankylosauridae, the two taxa can be distinguished on the basis of many features, such as tooth morphology and ischial shape, which are not ontogeny-related. Chuanqilong chaoyangensis represents the fourth ankylosaurid species reported from the Cretaceous of Liaoning, China, suggesting a relatively high diversity in Cretaceous Liaoning.