Topographical anatomy of the suprascapular nerve and vessels at the suprascapular notch

Morphology and Prevalence of the Inferior Transverse Scapular Ligament: Systematic Review, Meta-Analysis, and Proposal for Classification

Background/Objectives: The suprascapular nerve is most vulnerable to entrapment at the suprascapular and spinoglenoid notches, causing neuropathy. Numerous studies have examined the suprascapular notch and ligament and its relationship with suprascapular nerve entrapment, but few have examined the spinoglenoid notch and the inferior transverse scapular ligament (ITSL). This study summarizes all existing ITSL morphology studies and presents a simple and comprehensive classification system for different ITSL subtypes. Methods: A systematic review of the literature was conducted according to the PRISMA guidelines, searching the online databases PubMed and Embase. The references of each relevant article were further screened to find more eligible studies. The Anatomical Quality Assessment tool was used in order to further evaluate the quality of the records extracted. STATA MP 14 was used for the analysis in this study. Results: In total, 14 studies (995 scapulae; minimum: 1 and maximum: 268) were included in the present study. The overall ITSL prevalence was 5.8 (95% CI: 4.5-7.1) and the estimated odds for ligamentous vs. membranous type was 0.5 (95% CI: 0.3-0.7). The basic different morphological subtypes of the ITSL reported in the included studies are the band-like ligament, the fan-shaped ligament, the membranous ITSL, and the perforated membranous types. Conclusions: The ITSL represents an anatomical structure of mostly ligamentous nature. A single ITSL definition and standardization of its basic morphological subtypes along with an easy-to-remember and thus widely used classification system could greatly facilitate the comprehensive description, identification, and proper handling of this element across many surgical procedures.

Systematic Review and Meta-analysis of Suprascapular Notch Morphological Variability: Do We Know Everything?

The suprascapular notch represents a depression on the lateral part of the superior border of the scapula, medially to the coracoid process. The current paper presents a systematic review with a meta-analysis of the suprascapular notch morphological variability. Related clinical implications were further discussed as well to emphasize the value of the topic. A total of 31 articles were included in the meta-analysis, which depicted great heterogeneity. Thus, due to the different classification systems, difficulties were faced in creating a complete and united classification. All the problems and pitfalls that arise from each classification system were discussed, and we concluded with the most complete one. The knowledge of the suprascapular notch morphological anatomy is of great importance, especially for orthopedic surgeons, due to its relationship with the suprascapular nerve. Thus, further research in this area is adequate.

The Aberrant Origin of the Suprascapular Artery May Hide Neural Covariants: A Cadaveric Finding

The axillary artery is the continuation of the subclavian artery. Occasionally, some of the subclavian artery's distal branches may atypically originate from the axillary artery, such as the suprascapular artery. The suprascapular artery's distal (low) origin from the axillary artery, instead of the subclavian artery, may also be characterized as an aberrant suprascapular artery. The current cadaveric report describes the coexistence of an aberrant suprascapular artery (of axillary origin), variant course, and termination with atypically formatted nerves originating from the cervical (the phrenic nerve) and the brachial (the long thoracic and the median nerves) plexus. An unusual interconnection between the phrenic and the long thoracic nerves was also described. The aberrant suprascapular artery had an atypical termination below the superior transverse scapular ligament, along with the suprascapular vein and nerve. Except for the atypically formatted phrenic and long thoracic nerves, the aberrant suprascapular artery coexisted with an atypical passage of the anterior ramus of the C6 spinal nerve, through the middle scalene muscle, before the long thoracic nerve formation, and a variant formation of the median nerve. Understanding neurovascular variants is crucial for interventionists and surgeons who work in the supra- and infraclavicular areas. Being aware of the different origins of the brachial plexus branches, in the supraclavicular part, may help reduce the occurrence of iatrogenic axillary injury. Efforts should be made to expand the number of cadaveric studies that investigate the origin, course, interconnection, and branching patterns of these nerves and related covariants, in a systematic way, thus unifying their study and comprehension.

Variations in the Course and Diameter of the Suprascapular Nerve: Anatomical Study

(1) Background: Suprascapular neuropathy is an important factor contributing to shoulder pain. Given the prevalence of nerve injury and nerve block in the suprascapular notch region, as well as the frequency of arthroscopic procedures on the suprascapular notch, which are recommended in shoulder pain management, its morphology is relevant from a clinical perspective. (2) Methods: Suprascapular nerve course was studied in twelve shoulders by dissection. Its diameter was measured at omohyoid level, proximal to the suprascapular notch and distal to the spinoglenoid notch. A multi-vari chart was used in order to descriptively visualize the results. The variations found were analyzed with a mixed linear model. (3) Results: In two of the six subjects, the suprascapular nerve was divided into two motor branches proximal to the superior transverse scapular ligament. An increase in diameter around the suprascapular notch was detected, with an estimated difference between diameter means of 2.008 mm at the suprascapular notch level and 2.047 mm at the spinoglenoid notch level. (4) Conclusions: A difference in the estimated diameter detected and the fact that the motor branches, which innervate supraspinatus and infraspinatus muscle, were divided proximal to the suprascapular notch may be relevant in the diagnosis and treatment of suprascapular neuropathy and arthroscopic procedures.

Morphometry and Contents of the Suprascapular Notch with Potential Clinical Implications: Α Cadaveric Study

Background  The suprascapular notch (SN) represents the point along the route of the suprascapular nerve (SSN) with the greatest potential risk for injury and compression. Thus, factors reducing the area of the notch have been postulated for suprascapular neuropathy development.

Methods  Thirty-one fresh-frozen shoulders were dissected. The contents of the SN were described according to four types as classified by Polguj et al and the middle-transverse diameter of the notch was measured. Also, the presence of an ossified superior transverse scapular ligament (STSL) was identified.

Results  The ligament was partially ossified in 8 specimens (25.8%), fully ossified in 6 (19.35%), and not ossified in the remaining 17 (54.85%). The mean middle-transverse diameter of the SN was 9.06 mm (standard deviation [SD] = 3.45). The corresponding for type-I notches was 8.64 mm (SD = 3.34), 8.86 mm (SD = 3.12) was for type-II, and 14.5 mm (SD = 1.02) was for type III. Middle-transverse diameter was shorter when an ossified ligament was present (mean = 5.10 mm, SD = 0.88 mm), comparing with a partially ossified ligament (mean =7.67 mm, SD = 2.24 mm) and a nonossified one (mean = 11.12 mm, SD = 2.92 mm). No statistically significant evidence was found that the middle-transverse diameter depends on the number of the elements, passing below the STSL.

Conclusion  Our results suggest that SSN compression could be more likely to occur when both suprascapular vessels pass through the notch. Compression of the nerve may also occur when an ossified transverse scapular ligament is present, resulting to significant reduction of the notch's area.

Did the prevalence of suprascapular neuropathy in professional volleyball players decrease with the changes occurred in serving technique?

Objectives: Suprascapular neuropathy is more frequent in volleyball as compared to other overhead sports. This study aims to report the actual prevalence of suprascapular neuropathy among elite volleyball players. The hypothesis is that becoming jump topspin serves the most common serving technique, suprascapular neuropathy reduced its frequency. Methods: A total of 82 professional players were enrolled in the study. The presence of symptoms and the type of serve preferably performed were investigated. The strength and trophicity of the supraspinatus and infraspinatus muscles were evaluated. Patients with positive clinical findings underwent MRI of the shoulder. Results: The jump topspin serve was found to be the most popular type of serve both in males and females. At physical examination, 9% of the males and 12% of the females presented with infraspinatus muscle hypotrophy. Each case was accompanied by external rotation weakness. None of them complained of pain or reduced performance when they played. MRI confirmed infraspinatus muscle atrophy in all subjects. Conclusion: A lower prevalence of suprascapular neuropathy was found as compared with that previously reported in the 1980s and 1990s. A reduction in the popularity of the float serve seems to be a possible explanation. Thus, the jump topspin serve could be safe for suprascapular neuropathy and associated injuries in volleyball. The findings of this study should be considered by athletes and coaches for the prevention of activity-related injuries.

Applied anatomical study on suprascapular nerve protection in reverse total shoulder arthroplasty

BACKGROUND

This study aimed to investigate the three-dimensional (3D) anatomical relationship between the suprascapular nerve and scapula, and the method of protecting the suprascapular nerve in reverse total shoulder arthroplasty (RTSA) METHODS: In the present study, 12 fresh adult cadaver shoulder specimens were dissected. X-ray and computed tomography (CT) were used to investigate the 3D scapular and suprascapular nerve images.

RESULTS

The results revealed that the best fitting baseplate diameter was 24.73 ± 1.56 mm. Furthermore, the baseplate diameter correlated with the glenoid cavity width. After the osteotomy, a simulated screw placement on the baseplate was performed. The dangerous area for the posterior screw placement was at the angle between the upper edge and transverse axis exceeding 38° and between the lower edge and transverse axis exceeding 76°. The distance between the nearest point of the nerve and osteotomy plane was 15.38 ± 2.02 mm, and the angle between the projection point of the nearest point and transverse axis was 27.33 ± 7.96°, which was the dangerous area for retractor placement. The suitable angle between the superior screw and longitudinal axis was 21.67 ± 13.27°, and the suitable superior screw length was 34.66 ± 2.41 mm.

CONCLUSION

In RTSA, the baseplate size correlates with the glenoid cavity width. The relationship between the screw and suprascapular nerve and retractor placement position should be carefully considered to avoid damaging the suprascapular nerve.

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

BACKGROUND

Suprascapular 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).

PURPOSE

To 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 PROCEDURES

Observational 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 FINDINGS

The 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 CONCLUSIONS

The 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.

Coexistence of a rare case of a suprascapular artery with other vascular abnormalities: case report and potential surgical relevance

PURPOSE

The suprascapular artery originates in the thyrocervical trunk; however, several variations regarding both the origin and the path have already been described. This article aims to describe a complex and rare variation of the suprascapular artery originating as a branch of the subscapular artery. We described, reviewed the literature, and highlighted the clinical relevance of such variations to the medical practice.

METHODS

A routine dissection was performed on a male adult cadaver approximately 60-70 years old, embalmed in formalin 10%. In addition, the diameter of the axillary, subscapular and suprascapular arteries was measured.

RESULTS

During the dissection, we identified the suprascapular artery emerging from the medial side of the subscapular artery with a long and tortuous pathway to the supraspinatus fossa, under the superior transverse scapular ligament. Associated with this, three other anatomical variations stand out: the posterior circumflex humeral artery emerging from the subscapular artery, the absence of the anterior circumflex humeral artery, and two pectoral branches emerging from the third part of the axillary artery and from the subscapular artery, respectively.

CONCLUSION

Such variations are of great clinical relevance to orthopedists, mastologists, vascular surgeons and other specialties for both surgical approaches and suprascapular neuropathy.

An anatomical study of the superior transverse scapular ligament of Jining population

PURPOSE

The aim of this study was to determine the anatomical variations of the superior transverse scapular ligament (STSL) for better understanding the possible predisposing factors for suprascapular nerve entrapment.

METHODS

The study was using fifty 10% formalin solution-fixed human cadaveric shoulders. After dissection of the suprascapular region, the length, medial width, lateral width and middle width of the suprascapular opening were measured for each STSL.

RESULTS

The STSL displayed six types as: (1) band-shaped in 11 cases; (2) fan-shaped in 27 cases; (3) triangular-shaped in 5 cases; (4) linear type in 2 cases; (5) bifid in 1 case; (6) absent in 1 case. The ossified type of STSL was found in 3 cases. There were statistically significant differences in the length (P = 0.009), medial width (P = 0.001), lateral width (P = 0.029) of the three types of fan-shaped, band-shaped and triangular-shaped. However, there was no statistical difference in the middle width of the suprascapular opening of the three types (P = 0.340).

CONCLUSION

Knowing the morphological features and variations of the STSL is important for better understanding the anatomical conditions, which could be taken into consideration during open suprascapular operations or arthroscopic decompressions.

Morphological Aspects in Ultrasound Visualisation of the Suprascapular Notch Region: A Study Based on a New Four-Step Protocol

Background: Sonographic evaluation of the suprascapular notch (SSN) region is clinically important, because it is the most common location for performing suprascapular nerve block. The aim of the study was to describe the morphology of the SSN region based on ultrasound examination and in accordance with the patients’ body mass index (BMI). Material and Methods: The SSN region was sonographically examined in 120 healthy volunteers according to our new four-step protocol. The morphometry of the SSN and the neurovascular bundle was assessed, and patients’ BMI were calculated. The shape of the suprascapular notch was classified based on its superior transverse diameter (STD) and maximal depth (MD). Result: The type III scapular notch was the most prevalent (64%). The BMI was higher in type IV/V (27.38 ± 3.76) than in type I (24.77 ± 3.49). However, no significant differences were observed in the distribution of SSN notch types with regard to BMI (p = 0.0536). The suprascapular artery was visualised in all of the recognised SSNs, while the suprascapular vein and nerve were visualised only in 74.9% and 48.1% of the SSNs, respectively. The suprascapular nerve was significantly thicker on the right side (3.5 ± 1.1 mm) than on the left (1.3 ± 0.4 mm) (p = 0.001). In contrast, the suprascapular vein (1.5 ± 0.9 mm) was found to be a significantly wider on the left side than the right (1.2 ± 0.7 mm) (p = 0.001). Conclusion: Our original four-step sonographic protocol enabled characterising the morphology of the SSN region, despite the SSN notch types. The suprascapular artery is the best sonographic landmark for the suprascapular notch region. No significant differences were found between sides regarding the thickness of the soft tissue above the suprascapular nerve and vessels. Recognition of the SSN morphology is not affected by the BMI.

Variations in the origin and course of the suprascapular artery: case report and literature review

The suprascapular artery is normally a branch of the thyrocervical trunk of the subclavian artery. During dissection of the left upper limb of a female cadaver, aged 70 years and fixed in 10% formalin solution, the suprascapular artery was observed aberrantly arising from the first part of the axillary artery. Later, it coursed obliquely behind the clavicle bone and brachial plexus to reach the suprascapular notch, where it was accompanied by the suprascapular nerve. Then, both suprascapular nerve and artery anomalously traversed beneath the transverse scapular ligament. It then irrigated the supraspinatus muscles and took part in the anastomosis around the scapula. On the contralateral side there was no abnormality. Variations in the origin and course of suprascapular artery are of immense value to orthopedic and vascular surgeons, angiographists, and anatomists.

Protective and Predisposing Morphological Factors in Suprascapular Nerve Entrapment Syndrome: A Fundamental Review Based on Recent Observations

Suprascapular nerve entrapment syndrome (SNES) is a neuropathy caused by compression of the nerve along its course. The most common compression sites include the suprascapular notch and the spinoglenoid notch. The aim of this article was to review the anatomical factors influencing the occurrence of SNES in the light of the newest reports. Potential predisposing morphological factors include a V-shaped, narrow, or "deep" suprascapular notch; a band-shaped, bifurcated, or completely ossified superior transverse scapular ligament (STSL); particular arrangements of the suprascapular nerve and vessels at the suprascapular notch. A very recent report indicates structures at the suprascapular notch region that may protect from SNES, such as the suprascapular notch veins (SNV). The role of the anterior coracoscapular ligament (ACSL) is still not clear. While some studies indicate that it may predispose for SNES, the newest study proposes a protective function. Knowledge of these variations is essential for arthroscopic and other surgical procedures of this area in order to avoid iatrogenic injury of the suprascapular nerve or unexpected bleeding from the suprascapular vessels running alongside the STSL.

Open Anterior Release of the Superior Transverse Scapular Ligament for Decompression of the Suprascapular Nerve During Brachial Plexus Surgery

Reconstruction of the suprascapular nerve (SSN) after brachial plexus injury often involves nerve grafting or a nerve transfer. To restore shoulder abduction and external rotation, a branch of the spinal accessory nerve is commonly transferred to the SSN. To allow reinnervation of the SSN, any potential compression points should be released to prevent a possible double crush syndrome. For that reason, the authors perform a release of the superior transverse scapular ligament at the suprascapular notch in all patients undergoing reconstruction of the upper trunk of the brachial plexus. Performing the release through a standard anterior open supraclavicular approach to the brachial plexus avoids the need for an additional posterior incision or arthroscopic procedure.

The role of the peripheral and central nervous systems in rotator cuff disease

Rotator cuff (RC) disease is an extremely common condition associated with shoulder pain, reduced functional capacities, and impaired quality of life. It primarily involves alterations in tendon health and mechanical properties that can ultimately lead to tendon failure. RC tendon tears induce progressive muscle changes that have a negative impact on surgical reparability of the RC tendons and clinical outcomes. At the same time, a significant base of clinical data suggests a relatively weak relationship between RC integrity and clinical presentation, emphasizing the multifactorial aspects of RC disease. This review aims to summarize the potential contribution of peripheral, spinal, and supraspinal neural factors that may (1) exacerbate structural and functional muscle changes induced by tendon tear, (2) compromise the reversal of these changes during surgery and rehabilitation, (3) contribute to pain generation and persistence of pain, (4) impair shoulder function through reduced proprioception, kinematics, and muscle recruitment, and (5) help explain interindividual differences and response to treatment. Given the current clinical and scientific interest in peripheral nerve injury in the context of RC disease and surgery, we carefully reviewed this body of literature with a particular emphasis on suprascapular neuropathy that has generated a large number of studies in the past decade. Within this process, we highlight the gaps in current knowledge and suggest research avenues for scientists and clinicians.

Clinical evaluation of the shape of the suprascapular notch--an ultrasonographic and computed tomography comparative study: Application to shoulder pain syndromes

The most common site of suprascapular nerve compression and injury is the suprascapular notch. The aim of this study was to assess the sensitivity and specificity of sonography in determining the type of suprascapular notch (SSN). Thirty randomized patients (60 upper extremities) underwent USG examination of the shoulder area. The results were further compared with three-dimensional reconstructions of the scapulae obtained through CT examination to place the SSNs within a fivefold classification. For identification of type I, the sensitivity was 73.3% and the specificity 97.8%. For identification of type III, the values was 96.9% and 85.7%, respectively. Type II was not found in USG examination. Discrimination between type IV and V was not possible. The mean distance between the line connecting the edges of the SSN and the skin was 38 mm in right-handed patients and 34 mm in ambidextrous subjects. Ultrasonographic examination of the SSN is characterized by high specificity for type I, and high sensitivity for type III SSN. Discrimination between type IV and V of the SSN is not recommended based on sonographic evaluation.

The variable morphology of suprascapular nerve and vessels at suprascapular notch: a proposal for classification and its potential clinical implications

PURPOSE

The most common place for suprascapular nerve entrapment is the suprascapular notch. The aim of the study was to determine the morphological variation of the location of the suprascapular nerve, artery and vein, and measure the reduction in size of the suprascapular opening in each type of the passage.

METHODS

A total of 106 human formalin-fixed cadaveric shoulders were included in the study. After dissection of the suprascapular region, the topography of the suprascapular nerve, artery and vein was evaluated. Additionally, the area of the suprascapular opening was measured using professional image analysis software.

RESULTS

Four arrangements of the suprascapular vein, artery and nerve were distinguished with regard to the superior transverse scapular ligament: type I (61.3 %) (suprascapular artery was running above ligament, while suprascapular vein and nerve below it), type II (17 %) (both vessels pass above ligament, while nerve passes under it), type III (12.3 %) (suprascapular vessels and nerve lie under ligament) and type IV (9.4 %), which comprises the other variants of these structures. Statistically significant differences regarding the suprascapular opening were observed between the specimens with types II and III. Anterior coracoscapular ligaments were present in 55 from 106 shoulders.

CONCLUSION

The morphological variations described in this study are necessary to better understand the possible anatomical conditions which may promote suprascapular nerve entrapment (especially type III). They may be useful during open and endoscopic procedures at the suprascapular notch to prevent such complications as unexpected bleeding.

Arthroscopic decompression at the suprascapular notch: a radiographic and anatomic roadmap

BACKGROUND

Arthroscopic decompression of the suprascapular nerve (SSN) at the suprascapular notch is a technically demanding procedure. Additional preoperative and intraoperative information may assist surgeons. The purpose of this study was to (1) identify which imaging modality most accurately represents the anatomic distance to the notch and (2) quantify the mean intraoperative distances from routine arthroscopic portals to the notch.

METHODS

Ten matched pairs of fresh cadaveric shoulders were imaged by roentgenogram, computed tomography (CT), magnetic resonance imaging, and 3-dimensional (3D) CT, followed by arthroscopic SSN decompression at the notch and anatomic dissection. Measurements obtained included the distances from the anterolateral, posterior, and SSN portal sites to the notch in addition to the distance from the anterolateral acromion to the notch. Statistical analysis with Spearman correlation coefficients and Bland-Altman plots were used to determine the correlation and agreement between measurements.

RESULTS

The preoperative imaging modality with the highest correlation to anatomic distances from the anterolateral acromion to the notch was 3D CT (Rs = 0.90, P < .0001). The mean intraoperative distances to the notch from the anterolateral, posterior, and SSN arthroscopic portals were 89 mm, 88 mm, and 49 mm, respectively. The mean anatomic distance from the anterolateral acromion to the notch was 64 mm.

CONCLUSIONS

Preoperative imaging with 3D CT may assist surgeons in performing arthroscopic SSN decompression. Understanding of the mean distances from the portal sites to the suprascapular notch and being cautious of arthroscopic instruments placed beyond 9 cm from laterally based portals may result in safer intraoperative medial dissection.

New parameters describing morphological variations in the suprascapular notch region as potential predictors of suprascapular nerve entrapment

BACKGROUND

The suprascapular notch (SSN), bridged by the superior transverse scapular ligament (STSL), creates a pathway for the suprascapular nerve (SN). Morphological variations in the SSN region are common and can increase the risk of neuropathy by constricting the space for the nerve. The aim of this study was to establish new objective parameters that take this complex morphology into account.

METHODS

The SSN region of 100 formalin-fixed cadaveric shoulders was dissected. The dimensions of the SSN, the STSL and the anterior coracoscapular ligament (ACSL), as well as diameters of the SN, associated vessels and SN passage area, were measured by means of quantitative visual data analysis software to assign those structures to present classifications. The area reduction coefficient (ARC) and the ambit occupation coefficient (AOC) were defined and calculated for each shoulder.

RESULTS

The mean ARC and AOC for ligaments in the suprascapular region were: ARCSTSL = 71.6%, ARCACSL = 9.6%, AOCSTSL = 56.8% and AOCACSL = 9.1%. The SN passage area, ARC and AOC did not differ significantly between SSN types. The SN passage area and ARC differed significantly between band- and fan-shaped types of STSL. A significant relationship was observed between ARC and AOC (R=0.6855; p<0.0001). The SN passage area correlated significantly with ARC (R=-0.7555; p<0.0001) and AOC (R=-0.5609; p<0.0001).

CONCLUSIONS

The proposed parameters convey the complex morphology of the SSN region in a quantitative manner. The area reduction coefficient seems to be a more relevant indicator than the AOC as it better correlates with the SN passage area. Contrary to the SSN type, the STSL type significantly influences SN passage area and ARC.

The suprascapular vein: a possible etiology for suprascapular nerve entrapment and risk of complication during procedures around the suprascapular foramen region

INTRODUCTION

Nerve can be compressed when traveling through any osteo-fibrous tunnel. Any eventual anatomic structure limiting this passage increases the risk of neuropathy. During dissection of the shoulder region we recognized a vein travelling on the inferior border of the suprascapular notch together with the suprascapular nerve. The aim of this work was to evaluate the morphological characteristics of this vein in cadaveric material.

MATERIALS AND METHODS

The suprascapular notch (SSN) region was dissected in 60 cadaveric shoulders. The course, number and diameter of nerve and vessels in the suprascapluar notch region were evaluated. Length, proximal and distal width of the superior transverse scapular ligament were measured. Photographic documentation was taken to evaluate the suprascapular nerve passage area.

RESULTS

The vein identified was named as the suprascapular notch vein. It was present in 58.3% of shoulders. In 11 specimens, it was double. Its mean diameter was 1.7 mm (SD 0.7 mm) and did not correlate with the suprascapular nerve passage area. A suprascapular notch vein co-occurred more often with the anterior coracoscapular ligament (ACSL). In comparison with the SSN without the ACSL, it has a significantly greater diameter (2 mm; SD 0.7 mm vs 1.5 mm; SD 0.6 mm, respectively; P=0.021).

CONCLUSIONS

The suprascapular notch vein was a common structure that did not replace the suprascapular vein. Its presence correlated with the occurrence of the ACSL and was independent of body side, STSL type and SSN type.

TYPE OF STUDY

Observational anatomic study.

The superior transverse scapular ligament in fetuses

Introduction. The superior transverse scapular ligament (STSL) links the margins of the suprascapular notch and converts it into a foramen, through which, the suprascapular nerve and, on some rare occasions, the suprascapular vessels pass. This conversion often results from partial or complete ossification of the STSL and may produce compressive symptoms in the suprascapular nerve. Material and Method. Twenty shoulders from human fetuses were dissected without the aid of optical instruments and, using a digital pachymeter of precision 0.01 millimeters, length measurements and thickness measurements were made. The fetal age was from 21 to 33 weeks of gestation, with a mean of 27.6 ± 4.14 weeks. Results. There was no statistically significant difference in STSL length or any difference in the thicknesses at the medial and lateral extremities between the halves of the body (P ≥ 0.05). However, in the left half of the body, the medial extremity of the STSL was significantly thinner than the lateral extremity (P ≤ 0.05). Conclusion. Anatomical and morphometric details about the STSL were described in human fetuses. These findings, in fetuses, may encourage the pursuit of further studies to understand the morphofunctional role and meaning of this small ligament.

Anomalous origin and course of the suprascapular artery combined with absence of the suprascapular vein: case study and clinical implications

Background:

Variations concerning the origin and course of the suprascapular artery are numerous and present important clinical implications.

Aim:

In the present study the origin and course of the suprascapular artery are investigated in a sample of Greek (Caucasian) origin.

Materials and Methods:

The anatomy and course of the suprascapular artery were carefully examined in 31 adult human cadavers (16 male and 15 female).

Results:

Anomalous origin of the suprascapular artery from the third segment of the subclavian artery was observed in the right side of only one female Caucasian specimen (1/62 = 1.6%). The suprascapular artery and the suprascapular nerve passed together under the superior transverse scapular ligament through the suprascapular notch, whereas the suprascapular vein was absent.

Conclusion:

According to the available literature, this type of variation in the origin of the suprascapular artery is considered rare. This variation is clinically important, since it is related to the creation mechanism of suprascapular neuropathy and has also obvious surgical implications. The variation is embryologically enlightened and has an interesting ontogenic aspect.

Suprascapular vascular anomalies as a cause of suprascapular nerve compression

The vascular anatomy at the spinoglenoid and suprascapular notches appears to be more variable than previously thought. In patients presenting with signs of suprascapular nerve compression, vascular causes must be considered. Especially when considering percutaneous or arthroscopic treatment, awareness of these entities may help to guide treatment decisions, aid in identification of the anatomy, and prevent unwanted vascular insult.

The double suprascapular foramen: unique anatomical variation and the new hypothesis of its formation

A unique anatomical variation of the suprascapular notch was discovered in one scapula from 610 analyzed by three-dimensional CT reconstruction. Two bony bridges were found, converting it into a double suprascapular foramen, in the left upper extremity of an 56-year-old Caucasian female. This variation might be a risk factor for suprascapular nerve entrapment. Suprascapular nerve running through inferior suprascapular foramen was discovered. Suprascapular vessels passed through superior suprascapular foramen (artery lay medially and vein laterally). A new hypothesis of double suprascapular foramen formation (mechanism of creation) is presented based on recent anatomical findings (e.g., the discovery in 2002 of the anterior coracoscapular ligament). Knowledge of the anatomical variations described in this study should be helpful in arthroscopic and open procedures at the suprascapular region and also confirms the safety of operative decompression for the suprascapular nerve.

Variable morphology of the anterior coracoscapular ligament - a proposal of classification

INTRODUCTION

The suprascapular region is the most common site of compression and injury to the suprascapular nerve. This often results in suprascapular nerve entrapment, a possible risk factor being the anterior coracoscapular ligament (ACSL), a structure that runs in the suprascapular notch, below the superior transverse scapular ligament. The aim of the present study is to determine morphological variation of the ACSL and to measure the reduction in size of the suprascapular opening of specimens exhibiting it.

MATERIALS AND METHODS

A total of 84 human shoulders were included in the study. The following measurements were defined and performed for every ACSL: maximal length (ML), maximal proximal width (MPW) and maximal distal width (MPW). Additionally, two measurements of the suprascapular opening were collected: the area (aSSO) and the middle width (mwSSO). All of these measurements were taken using two independent methods: classical osteometry, and a new procedure based on the analysis of digital photographic documentation of the SSN taken using MultiScanBase v.14.02 software.

RESULTS

The anterior coracoscapular ligaments were present in 43 shoulders (51.2%). The analysis allowed the determination of four types of ACSL: first - fan-shaped (7%), second - band-shaped (62.8%), third - bifid (11.6%) and fourth - vestigial (18.6%). The mean area as well as the middle width of the suprascapular opening in the specimens with the anterior coracoscapular ligament was smaller than in those without this structure, however, no statistically significant differences were observed. The suprascapular nerve passed inferior to the ACSL in 2 specimens, and superior to it in 41.

CONCLUSION

The study presents a classification of the anterior coracoscapular ligament that has not been described in the literature and can be helpful in arthroscopic and open procedures of the suprascapular region. Knowledge of such anatomical variations confirms the safety of operative decompression to relieve entrapment of the suprascapular nerve.