Comparing a common clavicle maturation-based age estimation method to ordinary regression analyses with quadratic and sex-specific interaction terms in adolescents.

Established methods of age estimation are based on correlating defined maturation stages of bony structures with tables representing the observed range of biological ages in the majority of cases. In this retrospective monocentric study in southwestern Germany, common age estimation methodology was assessed in n = 198 subjects at the age of 25 or younger by analyzing the influence of age, quadratic age, biological sex and age-sex interaction on the ossification stages of the medial epiphysis fugue. Three readers (ICC ≥ 0.81 for left/right side) evaluated routine care computed tomography images of the clavicle with a slice thickness of 1 mm. By using least square regression analyses, to determine the real biological age a quadratic function was determined corrected for the age estimated by established methods and sex (R2 = 0.6 each side), reducing the mean absolute error and root mean squared error in the age estimation of women (2.57 and 3.19) and men (2.57 and 3.47) to 1.54 and 1.82 for women, and 1.54 and 2.25 for men. In women, the medial clavicle epiphysis seem to fuse faster, which was particularly observable from approximately 18 years of age. Before that age, the estimation method was relatively close to the ideal correlation between assessed and real age. To conclude, the presented new method enables more precise age estimation in individuals and facilitates the determination and quantification of additional variables, quantifying their influence on the maturation of the medial clavicle epiphysis based on the established ossification stages.

Sex determination using the clavicle by deep learning in a Thai population.

Determining sex is a critical process in estimating biological profiles from skeletal remains. The clavicle is interesting in studying sex determination because it is durable to the environment, slow to decay, challenging to destroy, making the clavicle useful in autopsies and identification which can then lead to verification. The goal of this study was to use deep learning in determining sex from clavicles within the Thai population and obtain the accuracies for the validation set using a convolutional neural network (GoogLeNet). A total of 200 pairs of clavicles were obtained from 200 Thai persons (100 males and 100 females) as part of a training group. For the deep learning approach, the clavicle was photographed, and each clavicle image was submitted to the training model for sex determination. Training groups of 200 samples were made. Images of the same size were input into the training model. The percentage of the validation set accuracy was calculated from the MATLAB program. GoogLeNet was the best training model and get the result of validation set accuracy. The results of this study found accuracies for a validation set with the highest overall right lateral view of the clavicle with an accuracy of 95%. Accuracy from the validation set of each view of the clavicle can demonstrate the forensic value of sex determination. A deep learning approach with clavicles can determine the sex and is simple to utilize for forensic anthropology professionals.

Assigned sex estimation with the clavicle and scapula: A study in a Portuguese reference sample.

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.

Micro-CT evaluation of morphological degenerative features of sterno-clavicular joint for age-at-death estimation in forensic anthropology - A qualitative analysis.

The analysis of the sternoclavicular joint holds significant importance in forensic anthropology, especially through the evaluation of medial clavicular ossification stage, which, however, is helpful only in subjects younger than 30 years of age. Given this limitation, the aim of the present work was to examine, through micro-CT, the surface of sternoclavicular joints of deceased individuals across various age groups, aiming to identify age-related degenerative changes applicable to age estimation in adults over 30 years old. A total of 41 deceased subjects were categorized into three age groups (20-39 years; 40-59 years; ≥60 years) for the analysis. Degenerative morphological features on both clavicular and sternal articular surfaces, including topography, porosity, and presence of osteophytes, were evaluated using a composite scoring system based on a modified "Falys-Prangle method.", which assigns to each parameter specific score ranges: 1-3 for surface topography (smooth, slightly irregular, markedly irregular), 1-6 for porosity (absent, micro- and macroporosity for <50 % or >50 % of surface, surface breakdown), 1-3 for osteophytes (absent, present, not evaluable). The findings revealed a positive correlation between degenerative morphological features and age for both clavicular (rs = 0.719) and sternal articular surfaces (rs = 0.750). Additionally, the combined assessment of the clavicle and sternum, or the evaluation of the clavicle alone, exhibited better differentiation among the three age groups. The micro-CT evaluation of degenerative alterations affecting the sternoclavicular joint proves to be a reliable and efficient method for age estimation in adults.

Measurement of Clavicular Symmetry in Healthy Subjects Using Tomographic Database of Public Hospitals / Mensuração de simetria clavicular em indivíduos saudáveis utilizando-se de banco de dados tomográficos de hospitais públicos

Abstract Objective This study aimed to perform an imaging evaluation to prove the existence or not of symmetry between the clavicles of healthy subjects from Curitiba, Paraná, Brazil, and identify potential factors influencing the clavicular length. Method The study analyzed chest computed tomography (CT) scans of 211 patients with no clavicular fracture or malformations (100 women and 111 men). We measured the greatest clavicular diagonal on both sides, and the software automatically generated the maximum distance in millimeters. Relative and absolute frequencies described qualitative variables and mean values; quantitative variables used a 95% confidence interval. Value comparisons employed the student's t-test, and correlations determinations used Pearson's correlation coefficient. The significance level adopted was 5%. Results There was a significant difference between the clavicular length (right clavicle, 143.58 mm; left clavicle, 145.72 mm; p = 0.037), indicating asymmetry. On average, the left clavicle was 3.71 mm larger. Asymmetry was significant for both men and women (p < 0.001). The average difference was 4.13 mm for men and 3.23 mm for women. Seventy-three percent of the sample had < 5 mm of asymmetry, 23.7% had 5 to 10 mm, and 3.3% had > 10 mm of asymmetry. Conclusion The studied population did not present clavicular symmetry. On average, the left clavicle was longer than the right clavicle, with differences of 3.71 mm in the general sample, 3.23 mm in women, and 4.13 mm in men. The only significant factor was gender since men presented longer clavicles and higher differences than women.

Resumo Objetivo Realizar avaliação imagiológica com intuito de comprovar a existência ou não de simetria entre as clavículas de indivíduos saudáveis da cidade de Curitiba/PR, aliada à identificação de possíveis fatores de influência no comprimento clavicular. Método Foram analisadas tomografias computadorizadas de tórax de 211 pacientes sem fratura ou malformações na clavícula (100 mulheres e 111 homens). A maior diagonal clavicular foi medida em ambos os lados e o software gerou automaticamente a máxima distância em milímetros. Foram utilizadas frequências relativas e absolutas para descrever variáveis qualitativas e a média e intervalo de 95% de confiança para as quantitativas. As comparações foram feitas com o teste t de Student e correlações calculadas pelo coeficiente de correlação de Pearson. O nível de significância adotado foi de 5%. Resultados Verificou-se diferença significativa entre o comprimento das clavículas (direita 143.58mm e esquerda 145.72mm, p = 0.037), indicando assimetria. Em média, o lado esquerdo é 3.71mm maior. A assimetria foi significativa tanto para homens quanto para mulheres (p < 0.001). A diferença média foi de 4.13mm para homens e 3.23mm para mulheres. 73% da amostra apresentou <5mm de diferença, enquanto 23.7% apresentou 5-10mm e 3.3% apresentou >10mm de assimetria. Conclusão Não foi possível encontrar simetria nas clavículas da população de Curitiba/PR. Em média, a clavícula esquerda é maior que a direita, com diferenças de 3.71mm na amostra geral, 3.23mm para mulheres e 4.13mm para homens. O único fator significativo foi o sexo, com homens tendo maiores comprimentos claviculares e maiores diferenças em comparação às mulheres.

A review of the coracoclavicular joint: Description, etiology, and clinical significance.

The coracoclavicular joint (CCJ) is a synovial joint that forms between the conoid tubercle of the clavicle and the coracoid process of the scapula in approximately 2.5% of the population. The number of bilateral to unilateral cases is almost equal. The number of right-sided and left-sided cases is also almost equal. It is found in both males and females but most often in male adults. Very few cases have been identified in juveniles. Found in populations all over the world, the highest frequencies of CCJ are in Asia. The etiology is unknown but it is most likely caused by metaplastic change of the trapezoid and surrounding tissue due to compression and friction of the coracoacromial ligament between the clavicle and coracoid process. Typically asymptomatic, but if so, the most common complaint is anterior should pain exacerbated by extreme abduction. Successful treatment includes steroid injection and surgical excision.

To be or not to be heavier: The role of dermal bones in the buoyancy of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis.

Stereospondyli are a clade of large aquatic temnospondyls known to have evolved a large dermal pectoral girdle. Among the Stereospondyli, metoposaurids in particular possess large interclavicles and clavicles relative to the rest of the postcranial skeleton. Because of the large size of these dermal bones, it was first proposed that they served as ballast during hydrostatic buoyancy control which assisted metoposaurids to live a bottom-dwelling mode of life. However, a large bone need not necessarily be heavy, for which determining the bone compactness becomes crucial for understanding any such adaptation in these dermal bones. Previous studies on the evolution of bone adaptations to aquatic lifestyles such as osteosclerosis, pachyostosis, osteoporotic-like pattern and pachyosteosclerosis have been observed in the long bones of secondarily aquatic amniotes. However, there are no known studies on the analysis of bone compactness in the dermal pectoral girdle of non-amniote taxa including Temnospondyli. This study looks at evidence of changes in bone mass adaptations in the dermal bones of the pectoral girdle of two stereospondyls occurring in the Late Triassic Krasiejόw locality (Southwestern Poland), namely: Metoposaurus krasiejowensis and Cyclotosaurus intermedius. However, because of lack of research on bone compactness of temnospondyls in general, there is no existent frame of reference to infer bone mass increase (BMI) in the M. krasiejowensis samples, and thus the bone compactness results of this taxon are compared with that of the samples of C. intermedius. Results of this study indicate that the interclavicles of M. krasiejowensis partially evolved BMI-like condition rendering these bones to be heavy enough to get selected as ballast during hydrostatic buoyancy control. Additionally, M. krasiejowensis shared its habitat with C. intermedius, however, the dermal pectoral girdle sample of the latter taxon does not display signs of BMI-like condition. Furthermore, the absence of variation in hydrostatic buoyancy control in the ontogenetic series of interclavicles of M. krasiejowensis could imply lack of ontogenetic niche shift along the water column.

Sex determination using scapular and clavicular parameters in modern Thai population / Determinación del sexo utilizando parámetros escapulares y claviculares en la población tailandesa moderna

SUMMARY: As natural disasters or crimes, precise postmortem identification is needed especially in case of unknown human remains. The aim of the study is to assess sexual dimorphism by formulating new multivariate equations based on scapular and clavicular parameters for a modern Thai population. Eight left scapular and six left clavicular parameters were measured from 278 individuals (124 males and 124 females for training group; and 15 males and 15 females for test group) of a modern Thai population with age ranges from 19 to 101 years. All scapular and clavicular parameters were sexually dimorphic. Direct and stepwise multivariate discriminant function analysis was performed to generate models. Three direct multivariate discriminant functions showed accuracy rates from 91.1c to 92.3 % (cross-validated range from 90.3 % to 91.5 %). Similarly, three stepwise multivariate discriminant functions showed accuracy rates from 90.7 % to 92.7 % (cross-validated range from 90.7 % to 92.7 %). Moreover, the test group showed 86.67 % to 100 % of sex determination accuracy in six discriminant functions. As recommendation for sex determination by using combination of the scapular and clavicular parameters yields statistically high accuracy for sex determination. Therefore, the accuracies of these multivariate discriminant function equations obtained from scapula and clavicle can be applied for forensic sex determination, especially in modern Thais.

RESUMEN: En casos de desastres naturales o crímenes se requiere una identificación post mortem precisa, especialmente en el caso de restos humanos desconocidos. El objetivo de este estudio fue evaluar el dimorfismo sexual mediante nuevas ecuaciones multivariadas basadas en parámetros escapulares y claviculares para una población tailandesa moderna. Se midieron ocho parámetros escapulares izquierdos y seis claviculares izquierdos de 278 individuos (124 hombres y 124 mujeres para el grupo de entrenamiento; y 15 hombres y 15 mujeres para el grupo de prueba) de una población tailandesa moderna con rangos de edad de 19 a 101 años. Todos los parámetros escapulares y claviculares presentaban dimorfismo sexual. Se realizaron análisis de funciones discriminantes multivariadas directas paso a paso para generar modelos. Tres funciones discriminantes multivariadas directas mostraron tasas de precisión de 91,1 % a 92,3 % (rango de validación cruzada de 90,3 % a 91,5 %). De manera similar, tres funciones discriminantes multivariadas mostraron tasas de precisión de 90,7 % a 92,7 % (rango de validación cruzada de 90,7 % a 92,7 %). Además, el grupo de prueba mostró del 86,67 % al 100 % de precisión en la determinación del sexo en seis funciones discriminantes. Como recomendación para la determinación del sexo mediante el uso de la combinación de los parámetros escapulares y claviculares, se obtiene una precisión estadísticamente alta para la determinación del sexo. Por lo tanto, las precisiones de estas ecuaciones de funciones discriminantes multivariadas obtenidas de la escápula y la clavícula se pueden aplicar para la determinación forense del sexo, especialmente en los tailandeses modernos.

Sex estimation from the clavicle using 3D reconstruction, discriminant analyses, and neural networks in an Eastern Turkish population.

Sex estimation of skeletal remains is an important aspect of forensic anthropology. The clavicle is a bone with relatively high accuracy in sex determination. In this study, 7 clavicular parameters were obtained using the CT images and 3D reconstruction of 360 cases equally distributed as 180 males and 180 females. Sex determination was made using univariate, linear, and stepwise discriminant analyses, and multilayer perceptron neural networks. Maximum sex determination accuracy of 85.3% was achieved with univariate analysis, 89.4% with linear discriminant analysis, 90.0% with stepwise discriminant analysis, and 91.4% with multilayer perceptron neural networks. Significant changes were observed in the MLC, APMD-R and CDC parameters according to age, and these were determined to affect the accuracy of sex determination in different age groups. In forensic anthropological studies, more reliable results can be obtained by considering the confounding factors during sampling. Although high accuracy rates can be achieved with neural networks, the results should be approached with caution.

A new analytical cut-off point for determining 18 years of age using MRI on medial clavicular epiphysis.

Evaluation of the ossification of the medial clavicular epiphysis plays a key role in forensic age estimation. The purpose of the present study was to assess a new numerical cut-off at the age of 18 years, taking into consideration Magnetic Resonance (MR) images of the medial clavicular epiphysis. We analyzed 163 MR scans of Italian subjects aged between 14 and 25 years. Using the data obtained we calculated two ratios: REM-1 (ratio between the length of the whole epiphysis and the length of the metaphysis) and REM-2 (ratio between the length of epiphyseal-metaphyseal fusion and the length of the metaphysis). In 68 out of 163 cases it was not possible to measure REM-2. The reproducibility was demonstrated using the Intraclass Correlation Coefficient (ICC) (Cronbach's alpha > 0.80). REM-1 and REM-2 were compared in each category of age (adult and minor) by the Wilcoxon signed-rank test. The cut-off points for measurements of REM-1 and REM-2 were determined by logistic regression. For REM-1, the cut-off scores were 0.83 for all individuals (accuracy = 94.77%) and males (accuracy = 96.05%), and 0.86 for females (accuracy = 92.30%). For REM-2, the cut-off values were 0.40 for all individuals and males (accuracy = 100.00%), and 0.41 for females (accuracy = 100.00%). Finally, receiver operating characteristic (ROC) curves for age classification based on REM-1 and REM-2 were constructed, showing that REM-2 had the highest discriminative power. Thus, a new cut-off model for predicting the age of majority has been introduced, conducting a quantitative analysis thanks to the use of a high-resolution imaging tool.

Contribution of the use of clavicle bone density in age estimation.

Age estimation is an essential element in the field of forensics and is also of judicial interest in forensic medicine of the living. Despite all the methods, age estimation is often imprecise with many biases, especially in mature individuals. The main objective of our study is to assess the correlation between age and computed tomography bone mineral density of the medial end of the clavicle. A sample of 180 chest multi-slice computed tomography scans without contrast injection performed in living individuals, with suspected respiratory infection, aged 15 to 100 years was used. Bone density measurement was performed on the medial meta-epiphyseal region of the clavicles. A significant negative correlation was found between bone density and age of individuals (p-value < 0.05). The mean absolute error was calculated for men at 13.4 years and 13.1 years for women, which was associated with an absence of bias. Good precision of the estimate for both sexes was also calculated on a subgroup of individuals whose age was greater than 40 years, with average absolute errors of about 12 years, which was associated with an absence of relative error. In view of our preliminary results, the study of bone density of the medial end of the clavicle could be of interest in the estimation of age. Several studies will be necessary to evaluate the reproducibility of these results on independent bone samples and in the estimation of age in the living individual.

Anatomy and Correlation of the Coracoid Process and Coracoclavicular Ligament Based on Three-Dimensional Computed Tomography Reconstruction and Magnetic Resonance Imaging.

BACKGROUND The anatomy of the coracoid process and coracoclavicular (CC) ligament have been described and the correlation between them has been assessed based on 3-dimensional computed tomography (CT) reconstruction and magnetic resonance imaging (MRI), which provide a guide for coracoclavicular ligament reconstruction. MATERIAL AND METHODS Data were collected from 300 patients who underwent both CT and MRI of the shoulder joint from January 2017 to January 2019 at the Jiang'an Hospital of Traditional Chinese Medicine. The coracoid process was observed and classified and parameters of the CC ligament were measured according to different corneal types. All of the statistics were collected and classified by 2 radiologists, and average values were determined.Measurements of segments were taken as follows: ab - In the coronal plane, the length of the CC ligament from the central point of the CC ligament at the clavicular attachment to the CC ligament at the center of the CC attachment); ac - The distance from the center point of the CC ligament at the supraclavicular attachment to the acromioclavicular joint; de - In the sagittal plane, the length of the CC ligament from the center of the clavicular attachment to the coracoid attachment point; fg - The maximum diameter of the CC ligament at the anterior and posterior margins of the clavicle attachment; hi - The largest diameter of the CC ligament at the anterior and posterior edge of the coracoid process attachment; dj - The distance of the coracoclavicular ligament from the center point of the coracoid process attachment to the coracoid process tip; kl - The distance in the supraclavicular plane from the coracoclavicular ligament to the subcoracoid process. RESULTS The analysis showed that there are 5 types of coracoid process: gourd (31%), short rod (20%), long rod (22.3%), wedge (10.3%), and water drop (6.3%). There were statistically significant differences between the lengths of the ac and hi segments in the among the wedge and gourd-type and the short rod and water drop-type coracoid processes. There were statistically significant differences between the lengths of the ab, de, and fg segments in the short rod, gourd, and long rod-type coracoid processes. There were statistically significant differences between the lengths of the ac, fg, hi, dj, and kl segments in the water drop, gourd, and long rod-type coracoid processes. CONCLUSIONS The present study indicated that measurement of the CC ligament and the different shapes of the coracoid process provide an anatomical basis for the diagnosis and treatment of shoulder diseases and the data can be used to improve the safety of CC ligament reconstruction.

Forensic age estimation using conventional radiography of the medial clavicular epiphysis: A systematic review.

Of the many roles that forensic anthropologists and medico-legal professionals need to perform, forensic age estimation is one of the most frequent and important. Scoring medial clavicular epiphyseal (MCE) fusion is a method used to estimate age in young adults. The aim of this systematic review is to assess the reliability and reproducibility of MCE fusion visualised by conventional radiography and scored by Schmeling's grading system to determine whether an individual has attained the age of 18 years. Four articles were acquired after screening 4589 articles across four databases, and these were subjected to qualitative and quantitative synthesis. The risk of bias was calculated in the qualitative synthesis using the QUADAS-2 tool. Horizontal box plots were constructed to see whether MCE fusion as visualised by conventional radiography can be used to ascertain whether an individual has attained the age of maturity (18 years). It was observed that stages 4 and 5 of the Schmeling's method of age estimation from MCE fusion are observed only in individuals aged ≥18 years. This indicates that MCE fusion, when visualised using x-rays, which are associated with less ionisation radiation compared to computed tomography, can be used to verify the attainment of the age majority in individuals.

Estimation of sex based on postcranial elements in European American and Latin American populations.

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.

Estimating age-at-death in burnt adult human remains using the Falys-Prangle method.

OBJECTIVES: The Falys-Prangle-method assesses age-related morphological changes to the sternal clavicle end (SCE), enabling the observation of mature adults from the 5th decade onwards in unburnt human skeletal remains. The aim of this study is to investigate the applicability of the Falys-Prangle-method on burnt human remains. MATERIALS AND METHODS: Fifty-two SCE of 40 cremated individuals (out of 86) from the William M. Bass collection of the Forensic Anthropology Center (Knoxville, Tennessee) of known age-at-death and sex are available for assessment. Surface topography, porosity, and osteophyte formation are evaluated, after which the calculated composite score is associated with the corresponding age range as described by Falys and Prangle. The method is also applied on an archaeological case study from Oudenburg, Belgium, dating to the Roman period. RESULTS: The assessed age ranges strongly agree with the true age ranges (α = 0.828), suggesting the Falys-Prangle-method to be applicable on burnt human remains. The case study from Oudenburg yields markedly improved age-at-death estimates, significantly enhancing our understanding of the age distribution within this community. DISCUSSION: Information on age-at-death is key in the construction of biological profiles of past individuals. The mature adult is often invisible in the archaeological record since most macroscopic age estimation methods do not distinguish beyond 46+ years old. Our study stresses the usefulness of a large-scale application of the Falys-Prangle-method, which will increase the visibility of mature adults, especially in archaeological burnt human skeletal collections, where such information is, at present, extremely difficult to obtain.

Anatomy and Embryology of the Thoracic Outlet.

The thoracic outlet is the space between the thorax and axilla through which the subclavian vein, subclavian artery, and brachial plexus travel from their central origins to their peripheral termini. Its bounds include the clavicle, first thoracic rib, insertion of the pectoralis minor muscle onto the coracoid process of the humerus, and the sternum. It contains three areas: the scalene triangle, the costoclavicular space, and the subcoracoid or pectoralis minor space. Aberrant anatomy is common in the thoracic outlet and may predispose patients to compression of the neurovascular bundle and development of clinical thoracic outlet syndrome (TOS). Much of this aberrancy is explained by the embryologic origins of the structures that comprise the thoracic outlet. A thorough understanding of this anatomy and embryology is therefore critical to the understanding of TOS.

Innervation of supraclavicular adipose tissue: A human cadaveric study.

Functional brown adipose tissue (BAT) was identified in adult humans only in 2007 with the use of fluorodeoxyglucose positron emission tomography imaging. Previous studies have demonstrated a negative correlation between obesity and BAT presence in humans. It is proposed that BAT possesses the capacity to increase metabolism and aid weight loss. In rodents it is well established that BAT is stimulated by the sympathetic nervous system with the interscapular BAT being innervated via branches of intercostal nerves. Whilst there is evidence to suggest that BAT possesses beta-3 adrenoceptors, no studies have identified the specific nerve branch that carries sympathetic innervation to BAT in humans. The aim of this study was to identify and trace the peripheral nerve or nerves that innervate human BAT in the supraclavicular region. The posterior triangle region of the neck of cadaveric specimens were dissected in order to identify any peripheral nerve branches piercing and/or terminating in supraclavicular BAT. A previously undescribed branch of the cervical plexus terminating in a supraclavicular adipose depot was identified in all specimens. This was typically an independent branch of the plexus, from the third cervical spinal nerve, but in one specimen was a branch of the supraclavicular nerve. Histological analysis revealed the supraclavicular adipose depot contained tyrosine hydroxylase immunoreactive structures, which likely represent sympathetic axons. This is the first study that identifies a nerve branch to supraclavicular BAT-like tissue. This finding opens new avenues for the investigation of neural regulation of fat metabolism in humans.

Sagittal orientation of coracoclavicular ligament reconstruction affects the stability of surgical repair.

BACKGROUND: The variation in the anatomic relationship between the coracoid and the clavicle affects the biomechanical stability of coracoclavicular ligament reconstruction (CCLR). METHODS: Three-dimensional computed tomography reconstruction of 85 patients was analyzed. Anatomic landmarks were used to derive the coracoclavicular sagittal reconstruction angle (sRA). The lateral concave angle, which indicated the shape of the distal clavicle, and the offsets between the clavicle and coracoid were also measured. To investigate the biomechanical effects of the sRA on CCLR, 7 computed tomography scans with different sRAs were 3D printed. Two reconstructions, a single trans-coracoclavicular tunnel and a looped reconstruction technique, were performed sequentially. Models were cyclically loaded at 70 N in the anterior, posterior, and superior directions. RESULTS: The mean sRA was 68° ± 9.3° (range, 47°-85°). The superoinferior offset between the clavicle and the coracoid and the lateral concave angle positively correlated with the sRA (r = 0.359 and 0.837, respectively; P ≤ .001), whereas the anteroposterior offset had a negative correlation (r = -0.925; P < .001). The sRA had a negative correlation with the anterior displacement of the clavicle (rho = -0.96; P < .001) and a positive correlation with the posterior displacement for both surgical techniques (rho = 1.0; P < .001). CONCLUSION: The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane. Low sagittal angles can reduce anterior stability, whereas high sagittal angles can reduce posterior stability of CCLR.

Radiological study of the Asian coracoid process and clavicle: Implications for coracoclavicular ligament reconstruction.

PURPOSE: Iatrogenic coracoid and clavicle fracture is a known complication of drilling bone tunnels during anatomic coracoclavicular ligament reconstruction (ACCR). This study aims to measure the dimensions of coracoid process and clavicle in an Asian population to evaluate the suitability of drilling coracoid and clavicle tunnels for ACCR in Asians. METHODS: Width measurements of 196 coracoids and 189 clavicles were obtained after reviewing all computed tomography (CT) scans of the shoulder performed over a 6 years period. Coracoid measurements were made on the CT slice which showed the maximum cross sectional width of the coracoid base. Medial to lateral measurements of the coracoid width were taken on an axial view, 4 mm above the identified junction of the coracoid base and glenoid base. Antero-posterior clavicle width was measured through a point directly above the midpoint of the coracoid and perpendicular to the long axis of the clavicle. RESULTS: The overall mean coracoid width was 14.8 mm ± 2.54 mm (range 9.2-23.3 mm) and clavicle width was 17.1 mm ± 2.72 mm (range 11.1-25.3 mm). CONCLUSION: The Asian coracoid process is smaller than its Western equivalent. More research is required to validate this conclusion as no cadaveric studies with equivalent measurement techniques have been performed on Asians. Given the potentially narrower dimensions of the Asian coracoid process, extra precautions are required to minimize the risk of iatrogenic coracoid and clavicle fractures.

Prevalence of the sternalis muscle in a sample of routinely dissected human cadavers.

PURPOSE: Sternalis muscle is an uncommon muscle head attaching between the sternoclavicular joint superiorly and the costal cartilage near the xiphoid process. METHODS: In this study, 36 cadavers (18 male, 18 female) were obtained through the Anatomical Board of the State of Florida and complete, routine musculoskeletal dissection was performed while adhering to all relevant laws and practices. RESULTS: Two examples of the sternalis muscle belly (5%) were identified, one in a black male and one a white female. The sternalis muscles were bilateral in both cases and each was formed of a single muscle belly. The superior attachments were continuous with the sternal attachment of sternocleidomastoid, and the inferior attachments connected to the costal cartilages. Sternalis did not cross the midline and the T2-T5 anterior intercostal neurovasculature associated closely with the muscle belly. In the female, a well-formed unilateral chondrocoracoideus muscle was apparent with a branch from the medial pectoral nerve closely associated on the deep surface. No other abnormalities in the chest, axilla, or brachial plexus were noted on either cadaver, and the pectoralis major and minor muscles were normally formed and innervated in both cases. CONCLUSION: This study supports other evidence in the literature that indicates the sternalis muscle has an average prevalence in the population of approximately 5%, and it appears across race and sex. Education about this structure is important for radiologists, surgeons, and doctors of physical therapy that may be involved in treatment and post-surgical rehabilitation of this region.