Infraspinous Fossa Research Articles

Scapular foramina - a systematic review with meta-analysis based on 3316 scapulae.

In the present study, we want to systematize the previous studies on the scapular foramina (SF) and nutrient foramina (NF) with emphasis on the clinical relevance of this topic. Although seemingly not important, radiologists, clinicians and surgeons should be aware of the presence and characteristics of the SF and NF and look out for possible mistakes that may cause harm to the patients during either the diagnostic process or surgery. A comprehensive search was conducted in multiple databases, including PubMed, Scopus, Web of Science, Embase, Cochrane Library and Google Scholar. The whole process was divided into three stages. In the first stage, the following search terms were used: ((scapular foramina) or (scapular foramen) or (scapular nutrient foramina) or (scapular nutrient foramen) or (scapula foramen) or (scapula foramina) or (scapula nutrient foramina)). The results of the present meta-analysis were based on a total of 3316 studied scapulae. A pooled prevalence of scapulae in which at least one SF was found was set to be 11.29%. The most common localization of the SF was found to be the infraspinous fossa, in which the SF occurred with the prevalence of 52.31%. Subsequently, a pooled prevalence of scapulae in which at least one NF occurs was established at 74.23%. The presented data contribute to a comprehensive understanding of the prevalence, distribution, and characteristics of suprascapular and nutrient foramina in scapulae, considering different topographical areas, genders, and sides.

A standardized protocol for needle placement in the infraspinatus muscle: an anatomical perspective.

This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection. The superior part was mostly observed near the spine of the scapula. The middle part was broadly observed within the infraspinous fossa. The inferior part showed variable location within the infraspinous fossa. The injection accuracy of the superior, middle, and inferior parts in the infraspinatus muscle was 95.8%, 100%, and 91.7%, respectively. Targeting the superior and middle parts for injection of the infraspinatus muscle is relatively more straightforward than targeting the inferior part. Targeting the inferior part of the infraspinatus muscle in this study was more challenging than targeting the superior and middle parts. Needling for electromyography should be performed with special care to avoid unintended muscle parts, which could lead to inaccurate data acquisition and affect the conclusions about muscle function.

A novel radiographic projection for the detection of a scapula body fracture in a Thoroughbred foal

SummaryThis case report describes the clinical and diagnostic imaging findings, treatment and outcome of a 3‐month‐old Thoroughbred foal referred for the evaluation of severe left forelimb lameness and presents the acquisition of a novel radiographic projection of the scapula used to achieve the diagnosis. No abnormalities were found with the standard radiographic examination of the left shoulder. A right dorsal 45° lateral‐ left ventral lateral oblique radiographic view was performed to evaluate the body of the left scapula. A longitudinal, minimally displaced fracture of the infraspinous fossa was diagnosed with this projection. Ultrasound was used in conjunction to confirm the diagnosis, assess the displacement of the fracture in the sagittal plane and evaluate soft tissue damage. The foal was treated conservatively with anti‐inflammatory drugs and stall rest. A radiographic follow‐up and clinical reassessment were performed, and the horse appeared sound, no atrophy of the region was appreciated and no radiographic abnormalities were found.

Morphometric analysis of adult Hippopotamus forelimb bones

Background: Understanding the adaptative changes in bone shapes among animals involves studying bone morphology. We examined adult hippopotamus (Hippopotamus amphibius)forelimb bones at the anatomy laboratory of Patuakhali Science and Technology University, Bangladesh. Samples were collected from Rangpur Recreation Park and Zoo between September 2021 and July 2022. Methods: Bones were processed by removing mud and boiled with water. Subsequently, hydrogen peroxide was used for one and a half hours to remove any remaining muscular tissues from the bones. Following this, the bones were air-dried under sunlight for a month. Measurements of key parameters including length, height, width, circumference, and weight were obtained using calibrated instruments, thereby ensuring precision. Results:The scapula displayed a pronounced and elongated spine – the spina scapulae – that demarcated the lateral surface into two distinct fossae: the supraspinous fossa and the infraspinous fossa. The distal expansion of the spine, known as the acromion process, consisted of the fused hamate process and suprahamate process. The head of humerus was round and featured two undivided tubercles: the greater or major and the lesser tubercle. On the medial surface, a small and shallow radial fossa was observed, while on the opposite side, a large and deep olecranon fossa was present. The proximal surface of the radius head exhibited concave fovea capitis radii, which articulated with the lateral condyle of the humerus. The shaft of the radius was slightly expanded in the cranio-caudal direction. Similarly, the shaft of the ulnahad a somewhat triangular shape, resembling the shape of the radius shaft. Medially, it had a convex facet that articulated with the radius, and cranially, the interosseous space between the radius and ulna was longer than the caudal view. Conclusions: The unique anatomical features and morphometric measurements of the forelimb bones in hippos can be beneficial for identification, radiographic interpretation, and forensic investigation. Furthermore, this study provides essential guidelines and insights for understanding appropriate anatomical parameters.

Morphological and morphometric study of the scapulae of Korean wild deer

Korean water deer (Hydropotes inermis argyropus; Heude, 1884) and Siberian roe deer (Capreolus pygargus; Pallas, 1771) are Korean wild deer classified in the tribe Capreolini. C. pygargus in Korea were previously considered a single species; however, it was recently suggested that roe deer living on Jeju Island (Jeju roe deer; Capreolus pygargus jejuensis) is a distinct subspecies from roe deer living on the Korean peninsula (mainland roe deer; Capreolus pygargus tianschanicus) based on several studies demonstrating genetic and morphological features. In this study, we suggests that the scapular morphology and osteometric data can be used for interspecies discrmination between Korean wild deer. To compare the morphological characteristics of scapula among the three groups of deer, we analyzed the features and nine osteomorphological measurements of 31 H. i. argyropus (14 males and 17 females), 18 C. p. jejuensis (4 males and 14 females), and 23 C. p. tianschanicus (16 females and 7 males). The estimated ages of the deer were over 32–35 months. Data were analyzed by one-way repeated measures analysis of variance with post hoc Duncan test and discriminant functional analysis (DFA). H. i. argyropus and C. p. tianschanicus had the smallest and largest scapulae, respectively. The scapulae of the three Korean wild deer had a similar triangular shape, which was obscured by the tuber of the scapular spine, pointed acromion, broad infraspinous fossa, narrow supraspinous fossa, and partial ossification of scapular cartilage in older deer. H. i. argyropus had certain distinctive features, including a caudally pointed acromion, a notch between the supraglenoid tubercle and glenoid cavity (NBSG), a glenoid notch, and no sexual dimorphism, except for the longest dorsal length (Ld) and the scapular index (SI). C. p. jejuensis had a larger scapular index (SI) (61.74 ± 0.74%), compared with the SIs of H. i. argyropus and C. p. tianschanicus. The unique features of the scapula in C. p. jejuensis include its S-shaped cranial border. The C. p. jejuensis had a cranially pointed acromion, less frequent presence of glenoid notch and NBSG, short length of supraglenoid tubercle, and no sexual dimorphism. The C. p. tianschanicus had elevated cranial margin of the glenoid cavity, and frequent presence of glenoid notch and NBSG, similar to the H. i. argyropus. Similar to C. p. jejuensis, C. p. tianschanicus had a cranially pointed acromion. However, sexual dimorphism was observed in C. p. tianschanicus. DFA using osteometric data showed 97.22% of specimens were classified correctly into their species, meaning the osteometric parameters can be used for interspecies discrimination of Korean wild deer. Our findings indicate that the scapular morphologies of the three Korean wild deer have certain similarities and differences, suggesting that C. p. jejuensis are distinct from C. p. tianschanicus.

Topographical study of scapular foramina and scapular nutrient foramina in dried skeletons

The aim of our study is to study the prevalence and anatomy of scapular foramina (SF) and scapular nutrient foramina (SNF) in dried skeletons from the Northeastern Thai population. A total of 150 dried scapulae were investigated. Both SF and SNF were identified using a metal wire with a diameter of 0.36mm. The number, locations, lengths, and diameters of SF were recorded. Subsequently, SNF were identified using the same metal wire. Their number and locations were recorded. Two observers performed the evaluations and measurements. SF were present in 78.0% of scapulae. They could have up to five openings. Eighteen types were found. On average they were longer in males (21.7 ± 5.0mm) than females (19.45 ± 4.6mm). The mean diameters of both the superior and inferior openings were significantly greater in females (p < 0.01). SNF, in contrast, were present in 100% of scapulae. They were located in the supraspinous fossa (36.7%), subscapular fossa (31.3%), infraspinous fossa (22.8%), and peri-glenoid area (10.0%). Unlike previous studies, the present study suggests that SF are normal anatomical findings, present in 78.0% of the scapulae investigated. Surgeons should be aware of both SNF and SF when operating or interpreting radiological findings.

Gross morphometric studies on scapula, humerus, radius, and ulna of the Royal Bengal Tiger (Panthera tigris)

The study was carried out to know the gross anatomy and morphometry of scapula, humerus, radius, and ulnar bones of forelimb of an adult Royal Bengal Tiger. The bones were collected from Bangladesh National Zoo, Dhaka, and processed scientifically in The Veterinary Anatomy Laboratory of Chattogram Veterinary and Animal Sciences University (CVASU). The scapula was somewhat a quadrangular shape having two surfaces, three borders, and three angles. Its lateral surface was unequally divided into supraspinous and infraspinous fossa by a well-developed spine which gradually diminished towards the proximal extremity. The acromion process was subdivided into thick triangular shaped suprahamate process and hamate process which was over hanged the glenoid cavity. The humerus of The Royal Bengal Tiger was a long bone with a spirally twisted shape. The body of the humerus was somewhat compressed laterally. The radius was a slightly twisted bone with an anteroposteriorly flattened shaft and two extremities. The proximal extremity had a concave facet and the distal extremity was expanded and was about twice the size of the proximal extremity. The ulna was longer than the radius and was flattened mediolaterally. The proximal extremity had an olecranon process, anconeus process, and facet for the humerus. The olecranon process possessed three tubercles. Some osteomorphometrical features in the bones of forelimb specified unique discrepancies for this species which were the key factors for interpretation in the field of radiology and forensic studies.

An unreported infraspinatus muscle variation—two-headed infraspinatus minor muscle and three-headed fusion with the teres minor muscle

The infraspinatus muscle is situated under the scapular spine in the infraspinous fossa and inserts into the greater tuberosity of the humerus. It is a component of a crucial shoulder muscle group, the rotator cuff. There are a few interesting additional muscles in the infraspinal region. In the literature they are called the infraspinatus superficialis, infraspinatus minor and infraspinatus accessory muscles. The infraspinatus minor muscle is described as a superficial muscle bundle running under the scapular spine. During routine anatomical dissection, an unreported variation of the infraspinatus minor muscle was found. It derived from the inferior surface of the scapular spine and the infraspinous fossa. It had two heads. The superior head inserted on the greater tuberosity of the humerus. The inferior head inserted on the tendinous part of the infraspinatus muscle. There was also an unusual fusion of the infraspinatus muscle with the teres minor muscle. In this paper we will discuss the anatomical and physiological relationships of this morphological variation.

Morphology and morphometric analysis of bones of the forelimb of giraffe (Giraffa camelopardalis)

We studied the bones of forelimb of male giraffe (Giraffa camelopardalis) to record the gross anatomical and morphometrical features of the scapula, humerus, radius and ulna. We observed some unique anatomical features that will be helpful for radiographic interpretation and forensic investigations. For this purpose all the bones of thoracic limb were collected timely from the burial ground, identified by their morphological features and finally measured after processing with chemicals. The scapula was a triangular flat bone and the lateral surface of scapula was unequally divided into supraspinous (fossa supraspinata) and infraspinous fossa (fossa infraspinata) by a welldeveloped spine (spina scapulae). The humerus was a major and massive bone in the appendicular skeleton to bear the total body weight. The average length of humerus was 56.17 cm that run from the shoulder to the elbow. It possessed a cylindrical diaphysis which was somewhat compressed laterally and two enlarged epiphysis namely-proximal epiphysis and distal epiphysis. The humeral head (coput humeri) was long and strongly curved cranio-caudally; while the distal end had condyles (condylus) and epicondyles (epicondylud laterialis). The radius and ulna were twin bones where radius was articulated craniolateral to the ulna proximally and craniomedial to the ulna distally. However, the ulna was the longest bone in the forelimb of giraffe. These bones were entirely fused in giraffe except two places namely- proximal and distal interosseous spaces

Anatomical aspects of the selective infraspinatus muscle neurotization by spinal accessory nerve

The suprascapular nerve (SSN) is commonly reconstructed by spinal accessory nerve (SAN) transfer. However, reinnervation of its branch to the infraspinatus muscle (IB-SSN) is poor. Reconstruction of the SSN in cases of scapular fractures is frequently neglected in clinical practice. The morphological study was performed on 25 adult human cadavers. The course and the length of SSN of minimal diameter of 2 mm within the trapezius muscle, the length of the distal stump of IB-SSN to its branching point and the length of the SSN available for reconstructive procedure were measured. The feasibility study of the SAN - IB-SSN neurotization performed by using a bony canal under the spine of scapula was performed. The mean distance of the SAN from the spine was 8.5 cm (±0.88) at the point where it perforates the trapezius muscle and 4.49 cm (±0.72) at the most distal part of the nerve. The mean length of the intramuscular portion of the nerve was 14.74 cm (±1.99). It ran under a mean latero-medial angle of 15.54° (±2.51). The mean distance between the medial end of the scapular spine and the SAN was 2.44 cm (± 0.64). The mean length of the IB-SSN was 3.6 cm (± 0.67). The mean length of the SAN stump which was mobilized from its original course and transferred to the infraspinous fossa to reach distal stump of the IB-SSN was 8.09 cm (±1.6). Direct SAN to IB-SSN transfer is anatomically feasible in the adult population.

Visual Observation of Apparent Infraspinatus Muscle Atrophy in Male Professional Tennis Players.

Background:Previous studies have reported visually observed apparent muscle atrophy in the infraspinous fossa of the dominant arm of overhead athletes. Several mechanisms have been proposed as etiological factors, including eccentric overload, compressive spinoglenoid notch paralabral cysts, and cumulative tensile suprascapular neurapraxia.Purpose:To report the prevalence of apparent infraspinatus atrophy in male professional tennis players and to determine whether the suspected atrophy correlates with objectively measured weakness of external rotation.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 153 male professional tennis players underwent a musculoskeletal screening examination that included visual inspection of the infraspinous fossa. Infraspinatus atrophy was defined as hollowing or loss of soft tissue bulk inferior to the scapular spine in the infraspinous fossa of one extremity that was visibly different from the contralateral extremity. This finding was observed and independently agreed upon by both an orthopaedic surgeon and a physical therapist during the examination. Also assessed were rotator cuff instrument-assisted manual muscle testing, visual observation of scapular kinesis (or motion), and glenohumeral joint range of motion for internal and external rotation and horizontal adduction.Results:In the 153 players, dominant-arm infraspinatus atrophy was observed in 92 players (60.1%), and only 1 player (0.7%) was identified with nondominant infraspinatus atrophy. A Pearson correlation showed a significant relationship between the presence of dominant-arm infraspinatus atrophy and dominant-arm external rotation strength measured in neutral abduction/adduction (at the side) (P = .001) as well as between the presence of dominant-arm infraspinatus atrophy and bilateral external rotation strength measured at 90° of glenohumeral joint abduction (P = .009 for dominant arm and .002 for nondominant arm). No significant correlation was found with scapular dyskinesis, glenohumeral range of motion, or instrument-assisted manual muscle testing of the supraspinatus (empty-can test).Conclusion:Visually observed infraspinatus muscle atrophy is a common finding in the dominant shoulder of asymptomatic male professional tennis players and is significantly correlated with external rotation weakness. This condition is present in uninjured players without known shoulder pathology and is not related to glenohumeral joint internal rotation, total rotation range of motion, or scapular dysfunction. Players with visually observed infraspinatus atrophy should be evaluated for external rotation strength and may require preventive strengthening.

Three-dimensional CT observation of position and movability of the scapula in the horse using carcasses of Falabella.

The three-dimensionally real position and movement of the scapula in the lateral side of the ribcage could not be clarified in the horse, since the body size of the horse is too large to apply the CT scanning and image analysis methods. In this study, therefore, we examined the position and the movability of scapula using a carcass of the Falabella which is one of the smallest breeds of the horse. The whole skeletal system in thoracic part of the Falabella could be three-dimensionally observed by CT scanning method. The three-dimensional images show that the scapula cranially slides and the ventral part of the scapula dorso-cranially rotates, when the shoulder joint moves to the most cranial position as simulation. The three-dimensional rotation angle was approximately 10 degrees. As a result of comparative osteology of the scapula between Falabella and the large draft horse, the infraspinous fossa was caudally enlarged in the larger draft horse, whereas the Falabella had narrower infraspinous fossa. We suggest that it may be due to the adaptational morphological change in the scapula bearing various body weights among breeds. The three-dimensional CT image analysis and the simulation in carcass contribute to the analysis of the bone movements of the horse during walking and running locomotion as well as the motion analysis from external functional-morphological data.

Gross anatomy of scapula in Tiger (Panthera tigris)

The present study was conducted on the scapula of five adult tigers to record the characteristic features of scapula bone. It was placed on lateral aspect of thorax, directed downward and forward. It was in the form of wide plate having scapular spine on lateral aspect. The height of spine increased gradually towards the distal end. The acromian process was subdivided into hamate process and suprahamate process. Hamate process overhanged the glenoid cavity. The suprahamate process was in the form of thin triangular plate directed backwards. The supraspinous fossa presented undulating surface in its middle. The infraspinous fossa was triangular and more or less flattened. Subscapular fossa was shallow and presented two prominent ridges. The caudal angle of the scapula was terminated in to glenoid cavity which was oval to quadrangular in shape. Cranial and proximal to the glenoid cavity prominent supraglenoid tubercle was observed which had hook shaped coracoid process. Scapula of both the sides were morphologically similar but the morphometrical values for the right scapula were non-significantly higher than the left counterpart (t less than 0.05), which may be of some biomechanical importance.

Therian postcranial bones from the Upper Cretaceous Bissekty Formation of Uzbekistan

The Upper Cretaceous (upper Turonian) Bissekty Formation of Uzbekistan produces the most diverse Cretaceous therian fauna including one stem marsupial and eleven stem placental taxa known from cranial and dental elements. Some isolated postcranial elements from the Bissekty Formation can be confidently attributed to some of these taxa based on morphology and size. The humeral fragments, astragalus, and calcanei attributed to the deltatheroidan Sulestes karakshi Nessov, 1985 are similar to these bones in other stem marsupials. Postcranial bones referred to Zhelestidae Nessov, 1985 and Asioryctitheria Novacek et al., 1997 possess plesiomorphic therian morphologies, which are also present in some stem marsupials. All fragments of scapula from the Bissekty Formation show a plesiomorphic morphology with a trough-like infraspinous fossa placed medially to the supraspinous fossa. Bones attributed to the stem placental Paranyctoides quadrans (Nessov, 1982) and to the zalambdalestid Kulbeckia kulbecke Nessov, 1993 indicate arboreal and cursorial specializations, respectively. In particular, Kulbeckia Nessov, 1993 is similar to Zalambdalestes Gregory et Simpson, 1926 in having long and distally fused tibia and fibula and a long calcaneal tuber. Its distal humerus has a deep trochlea, large medial trochlear keel, and large capitular tail separated from a cylindrical capitulum by a shallow groove. The upper ankle joint of Kulbeckia has the complete separation of medial and lateral astragalotibial articulations.

Evolution of the hominoid scapula and its implications for earliest hominid locomotion.

The higher primate scapula has been subject to many explanations of the putative "adaptive value" of its individual traits. However, the shift from the bone's position in above branch quadrupeds to its more posterolateral position in recent hominoids obviously required fundamental changes to its general form. We hypothesize that most features argued to be individually adaptive are more likely secondary consequences of changes in its fundamental bauplan, a view more consistent with modern developmental biology. We tested this hypothesis with scapular metrics and angles from a broad anthropoid sample. Our results support our hypothesis. Contrary to earlier predictions, vertebral border length differs little relative to body size in anthropoids, inferior angle position primarily reflects mediolateral scapular breadth, and supraspinous and infraspinous fossa sizes largely reflect scapular spine orientation. Suspensory taxa have cranially oriented glenoids, whereas slow clamberers and humans do not. Australopithecus most closely resembles the latter. Most scapular features can be explained by only two primary changes: (1) reduction in mediolateral breadth and (2) change in the glenoid position relative to the vertebral border with increased reliance on suspension, which led to a more cranially angled scapular spine. Virtually all other scapular traits appear to be byproducts of these two changes. Based on fossil morphology, hominids1 were derived from a last common ancestor primarily adapted for clambering and not for suspension. Scapular form in early hominids such as Australopithecus is therefore primitive and largely reflects the genus's general clambering heritage.

A computed tomography study on the correlation between the morphometry of the suprascapular notch and anthropometric measurements of the scapula.

The suprascapular notch is a clinically important site because it is the main site of injury and compression of the suprascapular nerve. Its shape and size are the most important factors in the aetiopathology of suprascapular nerve neuropathy. This article reports the first computed topography (CT) study on the correlation between the diameters of the suprascapular notch and anthropometric measurements of the human scapula. A total of 130 scans of shoulders by a helical 32-row multidetector CT scanner were retrospectively analysed. The following scapular measurements were performed: morphological length, morphological width, projection length of the scapular spine, maximal width of the scapular spine, length of the acromion, maximal length of the coracoid process, length of the superior border of the scapula, morphological height of the supraspinous fossa, length of the lateral border of the scapula, and morphological height of infraspinous fossa. The following suprascapular notch dimensions were measured: maximal depth, superior transverse diameter, middle transverse diameter. The maximum depth of the suprascapular notch correlates with the morphological length of the scapula, the length of the lateral border of the scapula and the morphological width of the scapula. The superior transverse diameter of the suprascapular notch correlates with the length of the superior border of the scapula and negatively with the length of the lateral border of the scapula. In addition it has been shown that the length of the superior border of the scapula correlates more closely with the superior transverse diameter of the suprascapular notch than the middle transverse diameter of the suprascapular notch. It could be supposed that humans with longer scapulae have deeper notches. It may be also concluded that scapulae with a wider superior border have a shallower suprascapular notch.

Arterial supply and anastomotic pattern of the infraspinous fossa focusing on the surgical significance

The clinical significance of the muscular branch of the circumflex scapular artery (CSA) has been underestimated during surgery involving the scapular osteocutaneous free flap, while the suprascapular artery (SSA) is vulnerable to damage during internal fixation of a scapular fracture. This study aimed to provide navigational guidelines for the positions of the suprascapular and circumflex scapular arteries at the infraspinous fossa and to identify the anastomotic pattern. Scapulae were carefully dissected following injection of liquid silicone into the suprascapular and circumflex scapular arteries. The artery diameters and the distances between landmarks were measured. Scapulae were classified according to the anastomotic morphology of the arteries. The suprascapular and circumflex scapular arteries had mean diameters of 1.7 and 2.1 mm, respectively. The mean horizontal distance from the root of the spine to the suprascapular artery was 90.3 mm, and the mean distance between the suprascapular and circumflex scapular arteries was 45.5 mm. The circumflex scapular artery was positioned along the lateral border at 68.7% from the inferior angle. Practical navigational guidelines for the positions of the suprascapular and circumflex scapular arteries have been provided, with the anastomotic pattern classified into two types and two subtypes. The results of the present study will help reduce donor-site morbidity and damage to these arteries during surgery in the scapular region.

Anatomical structure and nerve branching pattern of the human infraspinatus muscle

The function of the infraspinatus muscle, critical to rotator cuff function, is dependent upon the muscle's structure and innervation pattern. The morphology of the infraspinatus muscle has been inconsistently described in the literature. Additionally, the branching pattern of the suprascapular nerve in the infraspinous fossa has not been addressed in the literature. The purposes of this study were to determine: the arrangement of the infraspinatus muscle bellies; the branching patterns of the suprascapular nerve to the infraspinatus muscle; if the infraspinatus muscle was composed the neuromuscular compartments. Forty-eight infraspinatus muscles from 24 embalmed cadavers were studied using standard dissection techniques to determine morphological characteristics and innervation patterns. Results demonstrated that the infraspinatus muscles were comprised of three separate muscular partitions with each partition residing in a thin fascial compartment but all residing deep to the posterior scapular fascia. A first order suprascapular nerve branch was present in 91.6% of superior, 100% of middle, and 70.8% of inferior partitions. A first order nerve was present in all 3 muscular compartments of the same infraspinatus muscle in 62.5% of cases. Second order nerve branches were present in 8.3% of superior, 0% of middle, and 29.2% of inferior partitions. These findings help to determine a more complete and accurate understanding of the structure of the infraspinatus muscle. A better understanding of its structure could lead to a better understanding of the function of the muscle. Such information will enable more effective rehabilitation strategies for injuries involving the infraspinatus component of the rotator cuff.

Hypophosphatemic rickets is associated with disruption of mineral orientation at the nanoscale in the flat scapula bones of rachitic mice with development

Metabolic bone disorders such as rickets are associated with altered in vivo muscular force distributions on the skeletal system. During development, these altered forces can potentially affect the spatial and temporal dynamics of mineralised tissue formation, but the exact mechanisms are not known. Here we have used a murine model of hypophosphatemic rickets (Hpr) to study the development of the mineralised nanostructure in the intramembranously ossifying scapulae (shoulder bone). Using position-resolved scanning small angle X-ray scattering (SAXS), we quantified the degree and direction of mineral nanocrystallite alignment over the width of the scapulae, from the load bearing lateral border (LB) regions to the intermediate infraspinous fossa (IF) tissue. These measurements revealed a significant (p<0.05) increase in mineral nanocrystallite alignment in the LB when compared to the IF region, with increased tissue maturation in wild-type mice; this was absent in mice with rickets. The crystallites were more closely aligned to the macroscopic bone boundary in the LB when compared to the IF region in both wild type and Hpr mice, but the degree of alignment was reduced in Hpr mice. These findings are consistent with a correlation between the nanocrystallites within fibrils and in vivo muscular forces. Thus our results indicate a relevant mechanism for the observed increased macroscopic deformability in rickets, via a significant alteration in the mineral particle alignment, which is mediated by an altered spatial distribution of muscle forces.

3D Morphometric and Posture Study of Felid Scapulae Using Statistical Shape Modelling

We present a three dimensional (3D) morphometric modelling study of the scapulae of Felidae, with a focus on the correlations between forelimb postures and extracted scapular shape variations. Our shape modelling results indicate that the scapular infraspinous fossa becomes larger and relatively broader along the craniocaudal axis in larger felids. We infer that this enlargement of the scapular fossa may be a size-related specialization for postural support of the shoulder joint.