Supraspinous Fossa Research Articles

A study of morphology and morphometry of scapula in North Indian population and its evolutionary significance

Introduction. Morphometrics can quantify a trait of evolutionary significance and deduce something of their ontogeny or evolutionary relationships. The present study intends to establish the morphometric criterion of scapula in North Indians. This is of definite significance as bone morphology is known to be influenced by cultural, environmental and racial factors. Materials and methods. The present study was carried on 100 adult scapulae of unknown sex obtained from Department of Anatomy, Government Medical College, Amritsar. The parameters studied were length of scapula; maximum breadth of scapula; superoinferior length, transverse breadth and depth of supraspinous fossa; length of infraspinous fossa, maximum breadth of infraspinous fossa, infraspinous fossa breadth, groove for circumflex scapular vessels and its distance from lateral angle and inferior angle, ridge between origin of teres minor and teres major on lateral border of infraspinous fossa, length of attachment of teres minor on infraspinous fossa, length of attachment of teres major on infraspinous fossa; scapular index and infraspinous index. Results. The values of the parameters were found to be more on the right side except superoinferior length of supraspinous fossa, mean distance of the groove from the lateral angle and inferior angle. Mean scapular index and mean infraspinous index were 68.30 and 76.40 respectively. Discussion. The various morphologic parameters studied and morphometric values measured in our study can be used to compare the racial characteristics and study the evolutionary aspects in different populations.

The Suprascapular Artery as a Reference for the Evaluation of Supraspinatus Fatty Infiltration on Magnetic Resonance Imaging.

Fatty infiltration (FI) of the supraspinatus is commonly seen in chronic large-to-massive rotator cuff tears. Evaluating FI in patients with severe muscle atrophy can be confusing. The purpose of this study was to investigate the anatomic relationship between the suprascapular artery and supraspinatus muscle on magnetic resonance imaging (MRI) to provide a method for defining the border of the supraspinatus muscle on Y-view MRI. It was hypothesized that the branches of the suprascapular artery would encircle the supraspinatus muscle on Y-view and adjacent MRI slices and could be used for defining the supraspinatus outline on oblique sagittal images. Cohort study (diagnosis); Level of evidence, 3. A total of 172 shoulders that had undergone arthroscopic repair for large-to-massive rotator cuff tears were retrospectively included. Two methods, one based on the supraspinous fossa and trapezius (SF method) and the other based on the region bounded by the branches of the suprascapular artery (SA method), were used for defining the supraspinatus outline on Y-view MRI for the assessment of FI. Preoperative supraspinatus FI grade and tangent sign and postoperative tendon integrity were evaluated. Shoulder function was assessed using the American Shoulder and Elbow Surgeons (ASES) score and active range of motion. The branches of the suprascapular artery encircled the supraspinatus in all shoulders, with the diameter of the branches ranging from 0.5 to 3 mm. The agreement in supraspinatus FI grading between the SF and SA methods was 65.12%. When limited to the 61 shoulders with a positive tangent sign, the agreement dropped to 22.95% (κ = 0.032). The group (FI grade 2 by SA method and ≥3 by SF method) showed no significant difference in postoperative outcomes compared with the 2-vs-2 group but had significantly better postoperative ASES scores (P = .001) and active range of motion in forward elevation (P = .020) compared with the ≥3-vs-≥3 group. The tangent sign was positive in 92.16% of the 2-vs-≥3 group. The suprascapular artery is a reliable reference for the evaluation of supraspinatus FI. When a positive tangent sign presents, supraspinatus FI is likely to be overestimated if the hyperintensity outside the region bounded by the branches of the suprascapular artery is mistaken as FI.

Supraspinous Fossa: Anatomy and Pathology.

Supraspinous fossa is an important location in the periscapular region, which houses important structures such as the supraspinatus muscle and the suprascapular nerve. The supraspinous fossa can be affected by pathologies involving its contents (supraspinatus muscle and suprascapular nerve), osseous boundary (scapular body, distal clavicle, and spinous process), or superficial soft tissue covering it. In this pictorial review, we describe the detailed anatomy of the supraspinous fossa. We have also covered imaging of wide range of pathologies that can affect supraspinous fossa such as paralabral cyst, muscle edema/atrophy, malignancies (primary and secondary), and miscellaneous lesions (myositis ossificans, fibromatosis, nerve sheath tumor, etc.). An awareness of the imaging findings of these entities is essential for a radiologist to avoid misinterpretation and can aid a timely diagnosis.

Looking back over the shoulder: New insights on the unique scapular anatomy of the tapir (Perissodactyla: Tapiridae).

The musculoskeletal anatomy of the shoulder of many ungulates has been inferred from veterinary model taxa, with uniformity in muscle arrangements and attachment sites often assumed. In this study, I investigated the muscular and osteological anatomy of tapirs and their relatives (Perissodactyla: Tapiroidea), using a combination of gross dissection and digital imaging (photography and laser surface scanning). Dissections of three modern tapir species revealed that the m. infraspinatus originates from both supraspinous and infraspinous fossae for all species, lying on both sides of the distal scapular spine. The epimysial border between the m. supraspinatus and m. infraspinatus origin sites are marked in all species by an ossified ridge, sometimes extending the length of the scapular spine. This "supraspinous ridge" is clearly visible on the scapular surface of both modern and extinct Tapirus scapulae; however, the ridge does not appear present in any non-Tapirus tapiroids examined (e.g., Helaletes, Nexuotapirus), nor in other perissodactyls or artiodactyls. Moreover, the ridge exhibits a clearly distinct morphology in Tapirus indicus compared to all other Tapirus species examined. Combined, these findings indicate that the presence and position of the "supraspinous ridge" may represent a robust phylogenetic character for reconstructing relationships within tapiroids. Unfortunately, any functional locomotor outcomes or benefits of the m. infraspinatus straddling the scapular spine remains elusive. This study represents a firm reminder for anatomists, veterinarians, and paleontologists to (where possible) look beyond veterinary model systems when inferring musculoskeletal form or function in non-model organisms.

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.

The suprascapular nerve block (SScNB) is easily administered using a landmark-based technique: A cadaveric study to assess nerve staining post-injection.

The suprascapular nerve is an ideal target for nerve blockade to alleviate shoulder pain given its widespread innervation to the shoulder girdle. To widen availability of this treatment, we investigate whether an anatomical landmark technique can be adopted by novice injectors to provide efficacious blockade. Five injectors were recruited with varying experience. 10 shoulders of Thiel embalmed cadavers were injected with blue dye. Written instructions and an illustration of the Dangoisse landmark technique were provided prior to injection. Cadavers were dissected and the presence or absence of dye staining reported by three observers and a consensus agreement reached. Dissection demonstrated diffuse staining in the suprascapular fossa. 90% of shoulders had adequate staining of the suprascapular nerve directly, or distal branches, which would provide adequate anaesthesia. Inter-observer agreement was good (k = 0.73) for staining at the supraspinous fossa and excellent (k = 0.87) for staining distally. The technique was performed by novice injectors with a good success rate. This technique is reproducible by a range of clinicians to effectively provide anaesthesia of the SScN. Within a resource strained healthcare environment greater uptake of this technique is likely to be of benefit to a wider group of patients.

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.

THE SUPRASCAPULAR NERVE BLOCK (SSCNB) IS EASILY ADMINISTERED USING A LANDMARK-BASED TECHNIQUE: A CADAVERIC STUDY TO ASSESS NERVE STAINING POST-INJECTION

The suprascapular nerve is an ideal target for nerve blockade to alleviate shoulder pain given its widespread innervation to the shoulder girdle. Many techniques have been described. To widen the availability of this treatment we investigate whether an anatomical landmark technique can be easily learned by novice injectors to provide efficacious blockade.Five injectors were recruited with varying experience; from the novice medical student to an orthopaedic consultant. Five torsos (10 shoulders) were used. A single page of written instruction and illustration of the Dangoisse landmark technique was provided prior to injection of a Thiel embalmed cadaver bilaterally. A pre-mixed injectate with blue dye was used. Cadavers were dissected and the presence or absence of dye staining reported by 3 observers and a consensus agreement reached.Dissection demonstrated diffuse staining in the suprascapular fossa. 90% of shoulders were found to have adequate staining of the suprascapular nerve directly, or its distal branches, in a manner which would provide adequate anaesthesia. The inter-observer agreement was good (k = 0.73) for staining at the supraspinous fossa and excellent (k=0.87) for staining distally. The technique was easily performed by novice injectors with a 100% success rate.We demonstrate that this technique is reproducible by a range of clinicians to effectively provide anaesthesia of the SScN. The main risks are ineffective block (10% in this series) and of intravascular injection. Within a resource strained healthcare environment greater uptake of this technique is likely to be of benefit to a wider array of patients.

The scapular notch: a Uruguayan cadaveric study of 62 dry scapulae

Introduction: The scapular notch is a depression on the superior border of the scapula, located medially to the coracoid process, through which suprascapular nerve enters the supraspinous fossa. This paper aims to describe the main anatomical aspects of scapular notch, measuring anatomical parameters for identification of this region during surgical procedures, and compare the obtained data with previous worldwide publications. Material and methods: Sixty-two dry scapulae of Uruguayan specimens were studied at the Anatomy Laboratory of the Faculty of Medicine, Universidad Centro Latinoamericano de Economía Humana (UCLAEH) in Maldonado, and the Faculty of Medicine, University of the Republic in Montevideo, Uruguay, and analyzed for variations. Results: Of the 62 studied scapulae, 33 were right sided and 29 left sided. Anatomical variations were found in 19 specimens, which included 5 flattened shape notches (8.1%), and 14 ossified notches (22.6%), from which 4 (6.5%) were complete and 10 (16.1%) were incomplete. Scapular notch is located at an average distance of 66.7 mm (SD: 4.7) medially from the lateral border of the acromion. Conclusions: Anatomy of the scapular notch is variable. The scapular notch can be located at the junction between the medial two thirds and the lateral one third of the superior scapular border. Anatomical variations of this region play an important role in the development of entrapment neuropathies and in surgical considerations for brachial plexus injuries reconstruction.

Topographical Variations of Nutrient Foramina in the Dry Adult Scapula: A Cross-sectional Study

Introduction: The scapula is the shoulder girdle bone. Vascularity of this bone may arise from the subscapular and circumflex scapular arteries (on the lateral border), supra-scapular artery (on the superior border), deep branch of the transverse cervical artery (on the medial border), or a branch from the axillary artery (on the costal surface). Nutrient arteries associated with flat bones like the scapula have not received significant research in the past. Aim: To determine the number and location of nutrient foramina on the human dry scapula. Materials and Methods: This descriptive cross-sectional study was conducted in the Department of Anatomy of RG KAR Medical College, Kolkata, West Bengal, India.. The sample was gathered from August 2022 to January 2023. A total of 122 dry adult scapulae were studied (69 right and 53 left), irrespective of age and sex. The data obtained after thorough inspection was tabulated to obtain the results. The International Business Management(IBM) Statistical Package for Social Sciences(SPSS) software tool was used for statistical analysis, and inferences were drawn from the results. Results: The average number of nutrient foramina per scapula was five (ranging from 2 to 10). The most common location of the supraspinous fossa was 30.97%. On the costal surface, most of the nutrient foramina were found directly inferior to the suprascapular notch (30%), and on the dorsal surface, nutrient foramina were identified under the spine of the scapula (23.75%). Nutrient foramina were least present in the peri- glenoid area (15.28%). The Analysis of Variance(ANOVA) test showed homologous subsets between and within the different types of fossae. Conclusion: To maintain the health of the scapula, the nutrient artery must be preserved. Most scapulae had more than one nutrient foramina, located in specific areas on both the dorsal and costal surfaces of the shoulder blade. As a result, orthopaedic surgeons performing scapular surgery place great significance on their topographic understanding of the nutrient foramina. A knowledge of these variations aids surgeons in minimising blood loss during surgical implications around the pectoral girdle or scapular area in living patients.

Selective Suprascapular and Axillary nerve (SSAX) block – A diaphragm sparing regional anesthetic technique for shoulder surgeries

Interscalene block, the gold standard for shoulder surgeries is inevitably associated with phrenic nerve palsy, even at low volumes. The major innervation of the shoulder joint is by suprascapular nerve and axillary nerve. Suprascapular nerve block has been used commonly for postoperative analgesia in shoulder surgeries done under GA. Combining axillary block with suprascapular nerve block was found to provide superior analgesia when compared to suprascapular block alone. Selective Suprascapular and Axillary nerve (SSAX) block provides effective analgesia in shoulder surgeries without causing diaphragm palsy, but has limited published literature. We performed ultrasound guided suprascapular block in the supraspinous fossa (posterior approach) using 10 ml of 0.25% Ropivacaine and axillary block in the quadrangular space using 6ml of 0.25% Ropivacaine before administration of general anaesthesia (GA) in 4 cases. Among four cases, 2 were closed shoulder manipulation with intra-articular steroid injection for periarthritis, 1 was closed reduction and K-wire fixation for chronic shoulder subluxation and the 4th was Latarjet procedure for recurrent shoulder dislocation. All patients received paracetamol 1g at the end of the procedure and every 6 h postoperatively. No patient experienced pain during recovery and the analgesia lasted for a mean duration of 347.5 minutes. Tramadol was required for rescue analgesia in only one patient (Latarjet surgery). We found that SSAX block provided effective analgesia in all patients, but needs randomized controlled trials with larger sample size comparing with interscalene block.

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.

Subthreshold Peripheral Nerve Stimulation with a High Frequency Electro-Magnetic Couple Powered Implanted Receiver for the Treatment of Chronic Shoulder Pain

BACKGROUND: Shoulder pain has an estimated population prevalence of up to 26%. The most common source of shoulder pain is the rotator cuff, which is a group of muscles and tendons that surround the shoulder joint, accounting for over two-thirds of cases. CASE REPORT: A 65-year-old man presented with sharp, localized pain on abduction of the left shoulder due to a left rotator cuff tear. A diagnostic nerve block provided 100% short-term pain relief. Subsequently a peripheral nerve stimulator trial was offered to the patient, which was successful. The permanent peripheral nerve stimulator was implanted at the supraspinous fossa with the middle electrodes at the suprascapular notch. A receiver was inserted into the inner lumen of electrode array and the neurostimulator was coiled and fixated to the fascia. The following stimulation settings were used: frequency at 1.5 kHz, pulse width at 30 µs, and amplitude of 3.5 mA. CONCLUSION: At one year after implant, the patient had close to 100% pain relief and reported excellent mobility of the shoulder. Wirelessly powered peripheral nerve simulation was a successful option for this patient suffering from debilitating left shoulder pain due to a left rotator cuff tear. KEY WORDS: Chronic shoulder pain, glenohumeral osteoarthritis, peripheral nerve stimulator, suprascapular neuralgia

How to Insert Acupuncture Needles into the Subacromial Space through LI15

LI15 is an important acupuncture point to treat shoulder pain. There are 4 needling methods for LI15 in the textbook; 1 method requires the insertion of the needle horizontally between the acromion and the great tuberosity of the humerus with the arm lowered for supraspinatus tendonitis. This method is also applicable for all conditions of rotator cuff disease, but it has not previously been described in detail. Providing X-ray scans and describing needle direction and depth of insertion will provide evidence for needling with the arm down as an effective stimulation of the subacromial space. Firstly, for this technique, with the arm raised, a concave point is located between the front edge of the acromion and the humerus, and the lower upper arm. Secondly, the acupuncture needle is inserted slightly posteriorly towards the supraspinous fossa, in the direction of the supraspinatus tendon and to a depth of 30-40 mm.

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

The pectoral girdle of StW 573 (‘Little Foot’) and its implications for shoulder evolution in the Hominina

The ca. 3.67 Ma adult skeleton known as ‘Little Foot’ (StW 573), recovered from Sterkfontein Member 2 breccia in the Silberberg Grotto, is remarkable for its morphology and completeness. Preservation of clavicles and scapulae, including essentially complete right-side elements, offers opportunities to assess morphological and functional aspects of a nearly complete Australopithecus pectoral girdle. Here we describe the StW 573 pectoral girdle and offer quantitative comparisons to those of extant hominoids and selected homininans. The StW 573 pectoral girdle combines features intermediate between those of humans and other apes: a long and curved clavicle, suggesting a relatively dorsally positioned scapula; an enlarged and uniquely proportioned supraspinous fossa; a relatively cranially oriented glenoid fossa; and ape-like reinforcement of the axillary margin by a stout ventral bar. StW 573 scapulae are as follows: smaller than those of some homininans (i.e., KSD-VP-1/1 and KNM-ER 47000A), larger than others (i.e., A.L. 288-1, Sts 7, and MH2), and most similar in size to another australopith from Sterkfontein, StW 431. Moreover, StW 573 and StW 431 exhibit similar structural features along their axillary margins and inferior angles. As the StW 573 pectoral girdle (e.g., scapular configuration) has a greater affinity to that of apes—Gorilla in particular—rather than modern humans, we suggest that the StW 573 morphological pattern appears to reflect adaptations to arboreal behaviors, especially those with the hand positioned above the head, more than human-like manipulatory capabilities. When compared with less complete pectoral girdles from middle/late Miocene apes and that of the penecontemporaneous KSD-VP-1/1 (Australopithecus afarensis), and mindful of consensus views on the adaptiveness of arboreal positional behaviors soliciting abducted glenohumeral joints in early Pliocene taxa, we propose that the StW 573 pectoral girdle is a reasonable model for hypothesizing pectoral girdle configuration of the crown hominin last common ancestor.

Diagnostic block and radiofrequency ablation of the acromial branches of the lateral pectoral and suprascapular nerves for shoulder pain: a 3D cadaveric study

Background and objectivesAcromial branches of the lateral pectoral and suprascapular nerves have been proposed as targets for diagnostic block and radiofrequency ablation to treat superior shoulder pain; however, the nerve...

“Suprascapular canal”: Anatomical and topographical description and its clinical implication in entrapment syndrome

BackgroundSuprascapular nerve (SN) entrapment syndrome accounts for 1–2% of all shoulder pain. The SN travels within a space between the suprascapular notch (SSN) and the spinoglenoid notch (SGN). PurposeTo report a detailed topographical study of the suprascapular canal (SSC) and ultimately sort the different types of SN entrapment by its anatomical localization within the canal. Basic proceduresObservational study on 30 free dissected limbs of formaldehyde-fixed cadavers. The SN and vessels were traced as they passed through the SSC and the boundaries of the SSC were observed and documented. The SSC was then exposed by reflecting away the bordering muscles. Dimensions of the SSC as well as parameters of the SSN and SGN were measured using a digital caliper. Finally, a thorough literature review was made to survey the SN entrapment occurrence by site. Main findingsThe SSC is situated in the spinoglenoid fossa, has an average width of 13 mm, and runs underneath the supraspinatus muscle with an average distance of 25 mm between the SSN and SGN sloping in an infero-postero-lateral direction. The first segment represents the SSC entrance site and is composed of two spaces: osteofibrous and musculofibrous. The second segment is bordered by the supraspinatus muscle fascia, lateral margin of the supraspinous fossa, glenohumeral joint capsule, and the bony surface of the scapula (spinoglenoid fossa). This represents the SSC passage site. The third segment represents the SSC exit site around the spinoacromial arch at the SGN. Principal conclusionsThe SSC is defined as an osteofibrous canal running between the SSN and SGN enclosed by the supraspinatus fascia. It is anatomically composed of three segments: an entrance, a passage, and an exit. The distal SN passes through the SSC via five intervals that correspond to five potential sites of anatomical nerve entrapment: at the pre-entrance site, entrance site, passage site, exit site, and post-exit site. Each of those sites was found to be associated with specific causes and forms of entrapment.

Three-dimensional topography of scapular nutrient foramina

PurposeThe aim of this study is to describe the number and location of the nutrient foramina in human scapulae which can minimize blood loss during surgery.Methods30 cadaveric scapulae were macerated to denude the skeletal tissue. The nutrient foramina of 0.51 mm and larger were identified and labeled by adhering glass beads. CT scans of these scapulae were segmented resulting in a surface model of each scapula and the location of the labeled nutrient foramina. All scapulae were scaled to the same size projecting the nutrient foramina onto one representative scapular model.ResultsAverage number of nutrient foramina per scapula was 5.3 (0–10). The most common location was in the supraspinous fossa (29.7%). On the costal surface of the scapula, most nutrient foramina were found directly inferior to the suprascapular notch. On the posterior surface, the nutrient foramina were identified under the spine of the scapula in a somewhat similar fashion as those on the costal surface. Nutrient foramina were least present in the peri-glenoid area.ConclusionNinety percent of scapulae have more than one nutrient foramen. They are located in specific areas, on both the posterior and costal surface.