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Here we present an updated inventory and study of pectoral girdle remains recovered from the Sima de los Huesos (SH) site. Here, we describe the key morphological traits of adults and, for the first time, subadult specimens. Because morphological traits can change with age, we also discuss some shortcomings related to age estimation in postcranial fossil specimens. Adult clavicles from the SH are long with a low robusticity index and marked curvatures in the superior view. Among these traits, only extreme clavicular length seems to characterize subadult individuals. Neandertals share all these traits. In the case of the scapula, the SH specimens share a relatively long and narrow glenoid fossa with Neandertals. This trait is also present in subadult individuals. Additionally, most specimens from SH, adults, and subadults showed a dorsal axillary sulcus on the scapular lateral border, a trait also present in most adult and subadult Neandertals. These traits in adult and subadult specimens supports substantial genetic control for many of them in both human species., (© 2023 American Association for Anatomy.)

The estimation of biological sex is a critical step in the assessment of the biological profile of an anonymous skeletonized individual. In certain recovery circumstances, the most dimorphic skeletal areas, such as the pelvis, are absent or fragmented; in that case, other bones of the skeleton, including the clavicle and scapula, can be used to predict sex. The purpose of this research is to generate new models for the estimation of sex with clavicular and scapular measurements using a study-sample of 129 individuals with clavicle (65 males and 64 females) and 112 individuals with scapula (50 males and 62 females) from the Lisbon Identified Skeletal Collection (Portugal). A decision tree classifier (C4.5) and logistic regression (LR) were employed to create univariable and multivariable sex prediction models. Accuracy under cross-validation of the classification models is high (up to 93.8%), with minimal bias (<5%), particularly in the multivariable models. The proposed LR models facilitate the probabilistic estimation of biological sex, accounting for the significant overlap in the expression of sexual dimorphism., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

This study assesses the use of postcranial elements for sex estimation taking population variability into account. European American and Latin American populations are independently analyzed. Nine measurements from postcranial elements were collected from 72 European American individuals, and 59 Latin American individuals. Statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 15. Statistical analyses were conducted to corroborate that there were no intra- or interobserver errors. In both populations, significant differences were found on all measured traits between males and females, except Scapular Breadth in Latin Americans. According to Discriminant Function Analysis (DFA) in the European American population the Ulna Minimum Breadth of the Olecranon (UMBO) correctly classified 91.3% of individuals. When this parameter was combined with the Diameter of Humeral Head (HHD), the two correctly classified 98% of individuals. In Latin Americans, the UMBO correctly classified 82.4% of the individuals. When combined with HHD, the measurements correctly classified 79.4% individuals. UMBO is the most useful trait to correctly assign the sex of the remains in both populations. Including the HHD improved accuracy rates in the European American sample. These results are in agreement with previous studies, which named the humerus as one of the potentially useful bones to consider for sex estimation based on its accuracy. Thus, these two anatomical regions could be used alone or in combination with other methodologies for sex estimation, which is particularly important in situations of fragmentary remains and incomplete skeletons., (Copyright © 2020 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Objectives: Purported evolutionary shifts in shoulder structure have been linked to changes in hominin behavior and adaptation. Researchers use clavicle morphology to infer these shifts. However, there is a lack of empirical data underlying such predictive relationships. This study investigates how clavicle morphology affects articulated shoulder girdle and upper thorax configuration in humans., Materials and Methods: Landmarks and scalar measurements on the clavicle, scapula, and ribs 1-3 were collected from three-dimensional computed tomographic scans of living humans. Covariation between disarticulated and articulated morphology was assessed using partial least squares and regression analyses., Results: We found support for hypotheses linking combined dimensions of the clavicle, ribs, and scapula to resting protraction. Individuals with relatively short clavicles tend to exhibit protracted and elevated resting positions of the scapula. It is more difficult to predict superoinferior configuration, which is only minimally affected by clavicle curvature. Instead, the superoinferior position of the scapula on the thorax is governed equally by clavicle orientation and rib declination. Shoulder breadth is determined primarily by clavicle length, but orientation has a comparable effect. Therefore, reliable reconstructions of shoulder breadth can be established using clavicle length, together with consideration of orientation. Relationships between clavicle and thorax morphology are weaker., Discussion: Understanding the determinants of variation in human shoulder structure informs interpretation of skeletal remains. Our investigations describe how important aspects of shoulder structure can be inferred from disarticulated clavicles and we provide the attendant predictive equations. Future work on interspecific variation will improve skeletal reconstruction for more ancient hominins., (© 2019 Wiley Periodicals, Inc.)

Background and Objectives: Retroclavicular block is designed to overcome the negative aspects of the commonly utilized ultrasound-guided parasagittal approach to the infraclavicular block. However, this approach necessitates the needle traversing an area posterior to the clavicle inaccessible to ultrasound wave conduction. This study sought to document the structures vulnerable to needle injury during a retroclavicular block., Methods: A Tuohy needle was inserted using a retroclavicular approach to the infraclavicular block in 3 lightly embalmed cadavers followed by a catheter insertion 4 cm beyond the needle tip. The process was repeated on the contralateral side. With the needle and catheter in position, the cadavers were dissected and photographed., Results: In 4 of the 6 dissections, the needle was directly touching the suprascapular nerve deep to the clavicle. In the remaining 2 dissections, the suprascapular nerve was within 2 cm of the needle. In 1 dissection, the suprascapular vein was indented, behind the clavicle. The trapezius was the only muscle layer traversed by the needle in all dissections. In 3 of the 6 dissections, the catheter penetrated the posterior cord. In the remaining 3, the catheter threaded along the neurovascular bundle., Conclusions: The suprascapular nerve is consistently in the path of the block needle posterior to the clavicle. This raises the possibility of risk of injury to the suprascapular nerve when using this approach to the brachial plexus. Vascular injury is also possible deep to the clavicle, and because of the noncompressible location, caution is advised in patients with disordered coagulation.

This study compares the use of 0.05 and 0.10 alpha levels with the updated osteometric pair-matching model on two samples of the os coxa, scapula, and clavicle. The samples include the Forensic Data Bank, and the osteometric sorting reference used within the Defense POW/MIA Accounting Agency. Mixed-effects two-way analyses of variance were used to analyze bilateral asymmetry in the standard measurements. In total, 3,793,566 t-tests were conducted for osteometric pair-matching analysis. The results indicate high levels of exclusion power, and accuracy can be obtained with the os coxa and scapula. The clavicle standard measurements capture too much asymmetry causing a lower exclusion to accuracy ratio for osteometric pair-matching relative to other elements. Both 0.05 and 0.10 alpha levels provide acceptable levels of performance. A lower alpha level will result in higher accuracy with less exclusion, and a higher alpha level will result in lower accuracy with more exclusions., (© 2017 American Academy of Forensic Sciences.)

Abstract: Human skeletal remains exhibit sexual dimorphism, which is apparent in adult living individuals as well. Researchers from forensic and osteoarchaeological fields have a growing interest in establishing metric standards for sexing by use of discriminant function analysis. The present study focuses on providing sex estimation metric standards using measurements from the scapula and clavicle in a Modern Greek sample (Athens Collection) consisting of 107 male and 90 female skeletons. A total of seven measurements were taken: maximum scapular height and breadth, glenoid cavity height and breadth, maximum clavicular length, anterior and superior clavicular diameter. The calculation of Sexual Dimorphism Index showed a significant degree of sexual dimorphism on both bones ranging from 10% to 18%. Statistical analysis provided the discriminant functions with an accuracy of correct sex estimation between 84.9% and 91.4%, and showed that the highest accuracy rate was obtained from the left scapula measurements; proving that this bone can be a useful tool in providing an accurate sex estimation in skeletal remains of Modern Greek origin.

Objectives: Degrees of upper-limb bilateral asymmetry reflect habitual behavior and activity levels throughout life in human populations. The shoulder joint facilitates a wide range of combined motions due to the simultaneous motion of all three bones: clavicle, scapula, and humerus. Accordingly, we used three-dimensional geometric morphometrics to analyze shape differences in the glenoid cavity and linear morphometrics to obtain the degree of directional asymmetry in a medieval population., Methods: To calculate directional asymmetry, clavicles, humeri, and scapulae from 100 individuals (50 females, 50 males) were measured. Landmarks and semilandmarks were placed within a three-dimensional reconstruction of the glenoid cavity for analysis of shape differences between sides of the body within sexes., Results: Linear morphometrics showed significant directional asymmetry in both sexes in all bones. Geometric morphometrics revealed significant shape differences of the glenoid cavity between sides of the body in females but not in males. Both indicators of directional asymmetry (%DA and %AA) did not show significant differences between sexes. PLS analysis revealed a significant correlation between glenoid shape and two humeral head diameters only in females on the left side of the body., Conclusions: The studied population, perhaps due to a high level of activity, exhibited slightly greater upper-limb bone bilateral asymmetry than other agricultural populations. Results suggest that the upper limbs were involved in similar activity patterns in both sexes but were characterized by different habitual behaviors. To obtain comprehensive results, studies should be based on sophisticated methods such as geometric morphometrics as well as standard measurements. Am. J. Hum. Biol. 28:817-824, 2016. © 2016Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Powerful, accurate throwing may have been an important mode of early hunting and defense. Previous work has shown that throwing performance is functionally linked to several anatomical shifts in the upper body that occurred during human evolution. The final shift to occur is the inferior reorientation of the shoulder. Fossil scapulae show the earliest evidence of a more inferior glenoid in Homo erectus. However, where the scapula rests on the thorax is uncertain. The relative length of the clavicle, the only skeletal attachment of the scapula to the torso, is quite variable. Depending on which fossils or skeletal measures are used to reconstruct the H. erectus shoulder, either a novel, anteriorly facing shoulder configuration or a modern human-like lateral orientation is possible. These competing hypotheses have led to very different conclusions regarding the throwing ability and hunting behavior of early Homo. Here, we evaluate competing models of H. erectus shoulder morphology and examine how these models relate to throwing performance. To address these questions, we collected skeletal measures from fossil and extant taxa, as well as anthropometric (N = 36) and kinematic (N = 27) data from Daasanach throwers from northwestern Kenya. Our data show that all H. erectus fossil clavicles fall within the normal range of modern human variation. We find that a commonly used metric for normalizing clavicle length, the claviculohumeral ratio, poorly predicts shoulder position on the torso. Furthermore, no significant relationship between clavicle length and any measure of throwing performance was found. These data support reconstructing the H. erectus shoulder as modern human-like, with a laterally facing glenoid, and suggest that the capacity for high speed throwing dates back nearly two million years., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

It is reported that the coracoclavicular (CC) ligaments arise at a constant region, which is proportional to the size of the clavicle and the coracoid process. However, all cadavers in those studies were from whites or African-Americans. The aim of this study was to evaluate dimension and orientation of CC footprints in Chinese cadavers and to determine whether race-dependent differences in these measurements exist. A total of 172 shoulders from 87 Chinese cadavers were used in this study, and the CC ligaments including the coracoid and the lateral clavicle were exposed. After measurement of the length of the CC ligaments, the ligaments were dissected and the insertion sites as well as the footprint centers were identified and marked. Each CC insertion dimension and its distance to the bony landmarks were recorded. Ratios representing the distance from the clavicular landmarks to each footprint center divided by clavicular length and clavicular width were calculated. These ratios were calculated for the coracoid process as well. The mean length of the clavicle and the coracoid process was 139.9 ± 9.4 and 40.5 ± 4.0 mm. The distance from the lateral edge of the clavicle to the conoidal center and to the trapezoidal center was 35.7 ± 3.4 and 21.8 ± 2.7 mm, respectively. The distance from the tip of the coracoid to the conoidal center and to the trapezoidal center was 35.1 ± 3.2 and 29.7 ± 2.9 mm, respectively. The ratios of the distance to the conoidal center and to the trapezoidal center divided by clavicular length and coracoidal length were 25.5, 15.6, 86.8 and 73.4 %, respectively. While absolute differences in the origin of the CC ligaments exist between different races, the ratio of these origins to the size of the clavicle and the coracoid process is constant.

New data on the mechanisms of movements of the shoulder girdle and humerus of bats are described; potential mobility is compared to the movements actually used in flight. The study was performed on the basis of morphological and functional analysis of anatomical specimens of 15 species, high speed and high definition filming of two species and X-ray survey of Rousettus aegyptiacus flight. Our observations indicate that any excursions of the shoulder girdle in bats have relatively small input in the wing amplitude. Shoulder girdle movements resemble kinematics of a crank mechanism: clavicle plays the role of crank, and scapula-the role of connecting rod. Previously described osseous "locking mechanisms" in shoulder joint of advanced bats do not affect the movements, actually used in flight. The wing beats in bats are performed predominantly by movements of humerus relative to shoulder girdle, although these movements occupy the caudal-most sector of available shoulder mobility., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Malunion after mid shaft clavicle fractures has recently been recognized as a cause of pain and dysfunction of the shoulder. The mechanism that causes these complaints is however yet unclear. In this study we describe the kinematic changes that occur in the shoulder girdle due to clavicle shortening., Methods: An experimental cadaveric study was performed on five shoulders of three fresh frozen specimens. The specimens were fixed in an upright position that allowed free motion of the shoulder girdle. We measured position of the bony structures with an opto-electronic system (Northern Digital Inc., Waterloo, Ontario Canada) in rest and during in a series of motions. Measurements were done with a normal clavicle and after shortening of the clavicle by 1.2, 2.4 and 3.6 cm. The shoulders were moved manually by one of the researchers. We examined for changes in resting position and during movement that resulted from the experimental shortening of the clavicle., Findings: In the resting position, winging of the scapula increased with resultant changes in the orientation of the glenoid, acromio-clavicular and sterno-clavicular joints and an altered position of the clavicle. On average protraction increased by 20°, lateral rotation changed 12° and posterior tilt decreased by 7°. Clavicle shortening affected sterno-clavicular joint rotations but did not do so in the acromio-clavicular joint. In arm elevation the offset in scapula orientation at resting position stayed relatively constant over the full range of motion but the amount of disposition is progressive in relation to the amount of shortening., Interpretation: Shortening of the clavicle leads to significant changes in the shoulder girdle in resting position and in movement., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Sex estimation is the grounds for an accurate identification of unknown human skeletal elements. The need for reliable methods distinguishing males from females based upon various skeletal elements is evident in cases of commingled, eroded and/or missing remains. The aim of this work lays on establishing criteria for sex estimation from the scapula and the clavicle in modern Greeks. A total of 147 left scapulae and 147 clavicles (66 females and 81 males) were used in the study. Eight and six measurements were taken on the scapula and clavicle respectively and data were subjected to principal components analysis (PCA) and discriminant function analysis (DFA). Posterior probabilities for the classification of each individual are also calculated. Statistical analysis was carried out using the software PAST (Paleontological Statistics) and SPSS (Statistical Package for Social Sciences) 18. The results supported the existence of pronounced sexual dimorphism, which was mainly attributed to size differences among the two groups. Univariate and multivariate methods of statistical classification showed high accuracy for all scapular and most clavicular measurements, verifying their value as sex indicators in the under study population. We recommend the use of this method for sex assessment from the scapula and the clavicle in cases exhibiting over 95% probability of correct classification. This is regardless of the overall high degree of accuracy reported here, as the method of choice in forensic contexts should always be case-driven., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Background: The coracoclavicular joint has been described as an articulation found inconstantly between the coracoid process and clavicle. We often observe a small space bordered by the fascia which covers the anterior surface of the subclavius muscle and the coracoclavicular ligament. The aim of this study was to observe the space in detail and to discuss the functional role of the coracoclavicular joint., Materials and Methods: Sixteen shoulder girdles from eight Japanese cadavers were used in this study. The scapula, clavicle, and anterior half of the first rib were extracted en bloc together with the subclavius muscle and the surrounding fascia. After observing the motion of the scapula and clavicle, we investigated macroscopically the attachments of the coracoclavicular ligaments and the subclavius muscle, and the extension of the fascia., Results: The fascia divided laterally into two sheets: the anterior sheet attached to the trapezoid ligament and the posterior to the conoid ligament. Among the two sheets, the coracoclavicular ligaments, coracoid process, and clavicle, a small space was observed. This small space can be recognized as a part of the coracoclavicular joint. When manually moving the inferior angle of the scapula with the sternal end of the clavicle fixed, we observed that the clavicle collided with the trapezoid ligament on the superior surface of the coracoid process within the space and that the scapular motion was restricted by this collision., Conclusion: The coracoclavicular joint could be much more recognizable than in previous papers and play an important role in the normal function of the shoulder joint., Level of Evidence: Basic science study.

Accurate spatial location of joint center (JC) is a key issue in motion analysis since JC locations are used to define standardized anatomical frames, in which results are represented. Accurate and reproducible JC location is important for data comparison and data exchange. This paper presents a method for JC locations based on the multiple regression algorithms without preliminary assumption on the behavior of the joint-of-interest. Regression equations were obtained from manually palpable ALs on each bone-of-interest. Results are presented for all joint surfaces found on the clavicle, scapula and humeral bone. Mean accuracy errors on the JC locations obtained on dry bones were 5.2+/-2.5 mm for the humeral head, 2.5+/-1.1 mm for the humeral trochlea, 2.3+/-0.9 mm for the humeral capitulum, 8.2+/-3.9 mm for the scapula glenoid cavity, 7.2+/-3.2 mm for the scapular aspect of the acromio-clavicular joint, 3.5+/-1.8mm for the clavicular aspect of the sternoclavicular joint and 3.2+/-1.4 mm for the clavicular aspect of the acromio-clavicular joint. In-vitro and in-vivo validation accuracy was 5.3 and 8.5mm, respectively, for the humeral head center location. Regression coefficients for joint radius dimension and joint surface orientation were also processed and reported in this paper.

Objective: Displaced ipsilateral fractures of the clavicle and the glenoid neck are usually the result of high-energy trauma. The objective of this study is to evaluate the association of the glenopolar angle (GPA) with the clinical outcome of the floating shoulders., Methods: Seven patients treated conservatively and nine patients with clavicular fracture treated operatively were evaluated retrospectively. The GPA of the affected (a-GPA) and unaffected (u-GPA) shoulders, and the change (d-GPA) were measured. The Constant-Murley score of the affected (a-CS) and unaffected (u-CS) shoulders, and the change (d-CS) were measured at the last follow-up., Results: The mean follow-up was 25 months, and the score was 69.7 points. Patient age had no effect on the clinical outcome, and the change in GPA in the affected shoulder between the initial and last follow-up for the nonoperated and operated groups did not differ statistically (p > 0.05). There were positive correlations between a-CS and a-GPA (r = 0.760, p < 0.05) and between d-GPA and d-CS (r = 0.643, p < 0.05) and negative correlations between a-GPA and d-CS (r = -0.962, p < 0.05) and between d-GPA and a-CS (r = -0.703, p < 0.05)., Conclusion: The simple measurement of GPA may yield useful prognostic information and help in making decisions concerning the floating shoulder.

The goal of this study was to adapt roentgen photogrammetry to in vivo studies of shoulder skeletal motion during arm elevation in the scapular plane. Numerous in vitro and in vivo studies have been published describing shoulder bone movements. They involve plain radiographic measurements and utilize a three-dimensional (3D) approach. Measurements are either direct using pins implanted in bones, or indirect recording points on medical images. Roentgen photogrammetry locates points in space from two projections obtained from two different radiographic incidences. The technique has been applied in vivo by implanting metallic balls in bones. However, to be used as a standard clinical procedure, the technique must be adapted to be less invasive. In vivo photogrammetric reconstruction of known points in 3D space requires that the subject is strictly motionless between the successive radiographic exposures or that the exposures are obtained simultaneously. Methods used in this study were developed to allow subsequent exposures to be used for analysis. Numerical tools have been developed to align the two projections of a point in 3D space which have moved slightly between two successive exposures. The standard photogrammetric technique is completed by geometric modeling of the shoulder complex and humerus, and by the control of their mutual proximity at the level of joints. Bones are modeled as a set of simple volumes linked together using geometric shapes described by shape parameters. The coincidence between real bone contours and radiographic projections of the modeled bone gives the values of the shape parameters and the accurate location in space. Results focus on two different topics: errors related to the use of roentgen photogrammetry with successive exposures, and results obtained by applying roentgen photogrammetry to the in vivo shoulder complex. Results describing shoulder bone and joint displacements are presented for comparison with previously published results. The technique of roentgen photogrammetry can successfully be applied to patients. The radiographic protocol is simple, and data can be obtained easily and quickly from the digitized films. The data obtained from asymptomatic shoulders compared favorably with published values. Future research will focus on comparisons between kinematics of the symptomatic and asymptomatic contralateral limbs in volunteers.

Inter-population variability in long-bone and pelvic-bone growth during the Early Medieval period is examined. The materials comprise four archaeological populations: two Slavonic (Gars-Thunau, Zwentendorf, Austria, 10th-century AD), one Avar (Zwölfaxing, Austria, 8th-century AD), and one Anglo-Saxon (Raunds, England, 10th-century AD). Bone measurements are analyzed against dental age estimates in order to assess inter-population differences in growth rates for long-bone and os coxae bone dimensions. Growth curves of the upper and lower extremities of additional archaeological populations and a modern North-American population are also assessed. The expectation was that the greatest differences in growth patterns would be found between the Anglo-Saxon and the Austrian samples, due to their distinct genetic and biocultural background. Minimal differences were expected between the two Slavonic populations, as these were approximately contemporaneous, recovered from geographically close locations, and shared relatively similar archaeological contexts. Growth curves were estimated for each bone dimension by fitting least-squares fourth-order polynomials (which allowed testing of population differences by analysis of covariance), and iteratively estimating Gompertz growth curves. The results showed differences between bones in the extent of inter-population variability, with diaphyseal long-bone growth showing equivalent patterns across the four populations, but significant differences between populations in the growth patterns of distal diaphyseal dimensions of the femur and humerus and the dimensions of the ilium. Varying growth patterns are therefore associated with inter-population differences in absolute dimensions in relation to age as well as variations in growth velocities. Inter-population variability in growth curves in the case of femoral and humeral dimensions were most pronounced during infancy (0-2 years). The most consistent differences in bone growth and related dimensions are between Zwölfaxing and the other samples. No significant differences in growth were detected between the Anglo-Saxon and the Austrian populations., (Copyright 2005 Wiley-Liss, Inc)

The Miocene ape Nacholapithecus is known from rather complete skeletons; some of them preserve the shoulder joint, identified by three scapulae and one clavicle. Comparisons made with other Miocene and living apes ( Proconsul, Equatorius, Ugandapithecus) suggest that the mobility of the scapulohumeral joint was important, and scapular features such as the morphology and position of the spine and the morphology of the acromion and axillary border resemble those of climbing arboreal primates except for chimpanzees, gorillas, or orang-utans. From the size of the scapula (male Nasalis size), it is clear that the animal is smaller than an adult chimpanzee, but the clavicle is almost as relatively long as those of chimpanzees. Some features closer to colobine morphology reinforce the hypothesis that Nacholapithecus was probably a good climber and was definitely adapted for an arboreal life.

Since the first description of the coracoclavicular joint in 1861, many papers have been published reporting its occurrence, anatomical description, and geographical distribution. However, there are as yet no published articles with a convincing explanation for the rather variable forms of this variant. In this study, we investigated the occurrence of the coracoclavicular joint in the current and medieval population of Toulouse city and propose, through biometric measures, an explanation for the different forms of this anatomical variant. A total of 2192 chest X-rays taken for various conditions at a receiving hospital and 392 specimens (784 scapulae and an equal number of clavicles) of the L'Isle-Jourdain Series were examined with this aim. When present in the osteologic collection, the sizes of the articular conoid process as well as the height of the corresponding coracoid and acromial processes were noted. A coracoclavicular joint was noted in 0.82% and in 1.78% of the individuals examined in the radiological and osteologic series, respectively. The conoid process varied in size and correlated with the disposition of each correspondent coracoacromial arch. Osteoarthritis was noted in some of these joints when there was discordance between the conoid process size and the architecture of the correspondent coracoacromial arch, suggesting impingement. Our findings support a genetic origin for this variant, and suggest that its occurrence is also probably influenced by environmental factors. Osteoarthritis of this joint may be responsible for shoulder pain.

The clavicle has been described as a useful bone for the metric determination of sex of human skeletal remains in a contemporary, predominantly white, North American forensic sample. In this article, measurements of clavicle and scapula are provided for a contemporary Guatemalan rural indigenous sample of forensic origin. Maximum length and circumference at midshaft of the clavicle, and height and width of the glenoid fossa of the scapula, were measured in 35 female and 62 male clavicles, and in 38 female and 65 male scapulae. Discriminant function analysis was used to study sexual dimorphism in this population with a classification purpose. Leave-one-out method (jackknife) matrices produced classification success rates ranging from 85.6% to 94.8%. A comparison with the North American forensic sample showed low percentages of correctly sexed Guatemalan male clavicles, ranging from 29.4% to 54.9%. The choice of an appropriate standard for the metric determination of sex is a crucial step in forensic anthropology.

During dissection practice in 1993 and 1995 to 1999, we found an aberrant muscle which connected the first costal cartilage and the superior margin of the scapula in 12 sides (4.8%) of 11 cadavers (8.9%) among 248 sides of 124 cadavers. The muscle originated from the cranial surface of the sternal end of the first rib, ran laterodorsally, and inserted into the superior margin of the scapula. According to the origin and insertion, the aberrant muscle was considered to be the subclavius posticus (Rosenmüller, 1800). We also examined the supraclavicular region of a living subject by MR imaging to estimate the course of such an aberrant muscle. It is thought that the aberrant muscle runs on the anterior surface of the subclavian vein and crosses over the brachial plexus. Such a muscle could be considered as a possible factor causing the Paget-von Schrötter syndrome which is recognized as spontaneous or effort-related thrombosis of the axillo-subclavian vein. It is recommended to take into account the possible existence of such an aberrant muscle during the examination of patients with thoracic outlet syndrome, especially in those with symptoms of venous compression.

This study was performed to investigate the occurrence of the coracoclavicular joint in Koreans. Materials used in this study were paired clavicles and scapulae obtained from 102 adult Korean cadavers (61 males, 41 females) ranging from 18 to 97 years in age. The occurrence of the joint was identified by a definite articular facet on the conoid tubercle of the clavicle and also by one on the superomedial surface of the coracoid process of the scapula. To compare the morphometric differences between specimens with and without coracoclavicular joint, the clavicle length, scapular border length, glenoid length, coracoid height, coracoacromial (CA) arch height, coracoid slope, and acromion slope were measured on all bones examined. The coracoclavicular joint was found in 10 (9.8%) of 102 individuals examined. Among them, nine (8.8%) showed bilateral coracoclavicular joints, and a unilateral right joint was noted in one case (1.0%). No significant difference in the incidence of the joint was noted between the right and left side. The incidence of the joint in males, a frequency of 9.8%, was the same as that in females. The joint was not found in individuals under 40 years old. However, the joint was present in 9.5% of those aged 40-59 years, and in 11.4% of those aged 60 years or over. There was no significant difference between various measurements taken from specimens with and without a coracoclavicular joint. These findings suggest that the occurrence of the coracoclavicular joint is related to aging, but not to the size of the scapulae or the slopes and heights of some CA arch elements.

The scapulae, clavicles and humeri recovered from the Sima de los Huesos (SH) site between 1976 and 1994 are studied. All elements are briefly described anatomically with metrics and compared with other fossil hominids in order to establish the morphological pattern of the SH hominids. A minimum of 13 individuals are represented by the humeri in the SH sample. Almost all of them can be classified as adolescents and young adults. The morphology of the SH hominid shoulder girdle and humeri indicates that much of the shoulder morphology recognized in the later true Neandertal was present in Europe long before they appeared. Thus, this morphological pattern is not exclusive to Neandertals alone. The SH clavicles, scapulae and humeri share with the Neandertals many traits usually considered to be Neandertal specializations. The comparative analysis of the SH evidence suggests that most of the SH and Neandertal shared traits are either primitive features within the genus Homo or even for all hominids, or display high variability within different hominid samples. These traits must be used with caution, or not used at all, in phylogenetic analysis. There are, however, traits that to date have only been detected in the SH hominids and the Neanderials, which could be exclusive to the European phyletic lineage (clade) of Homo.

The distance between the clavicle and the coracoid process of the scapula is frequently assessed during the radiographic investigation of the acromioclavicular joint. This study defines an ultrasound technique (5 MHz real time linear array) for measuring the coracoclavicular distance, and determines its reliability and validity. A new ultrasonic technique was performed on 49 healthy subjects who had volunteered to participate in the study, having given signed, informed consent. The measuring endpoints for the coracoclavicular distance were the superior border of the clavicle and the superior border of the coracoid process. Three replicate scans were performed on each shoulder. The ultrasound measurements for 19 of the subjects were compared with the measurement obtained from a normal shoulder radiograph (which had previously been requested on clinical grounds). The data were subjected to analysis of variance (ANOVA) and the limits of agreement method of analysis. The mean difference between the radiograph and ultrasound measurements was 0.38 mm. The limits of agreement (95% confidence intervals) were -0.57 (-0.97, -0.17) and 1.33 (0.93, 1.73). Intraoperator and interoperator reliability were evaluated with a multifactor ANOVA and gave p = 0.7 for intraoperator reliability and p = 0.5 for interoperator reliability. The mean of the coefficients of variation for the two operators was 1.84%. The average range for repeated trials (same operator, same subject) was 1.35 mm. The maximum differences in the averages for each operator was 1.2 mm. The ultrasound technique described is a reliable, accurate and valid technique for evaluating the coracoclavicular distance and may usefully supplement the routine radiographic examination of the shoulder in patients presenting for radiographic examination of the acromioclavicular joint.

On the basis of published anatomical and skeletal anthropological surveys supplemented by published and unpublished commissioned radiologic surveys, the distribution of coracoclavicular joints in the world is described. The findings are in keeping with a focus having developed in central Asia in Pleistocene times. Thus, this anatomical variant can serve, by regression, as a marker for population migration from prehistoric times to the present.

The present study shows that the coraco-clavicular joint should be recognised as a normal human joint that is present in a large number of people of all races. Its presence does not confer any overt advantage but neither does it give rise to any trouble. It is possibly an evolutionary joint that has arisen from the approximation of the clavicle to the coracoid and new conditions of use in man where complex movements are possible at the shoulder. The genetic basis for this joint has been elucidated and it is inherited in a simple Mendelian fashion.

The coracoclavicular joints are genetically determined anatomic variants. There are problems in determining their presence by dissection examination of osteologic material as well as by radiography. Based on a survey of published material and a prospective radiological survey carried out in Malaysia, it is clear that the anomaly is more frequent in Asia than in Europe and Africa. There is a high incidence in people from Southern China. The joints are subject to osteophytic marginal lipping without development of symptoms or disability.