Proposal for classification of the suprascapular notch: A study on 423 dried scapulas

Three-Dimensional Morphological Analysis of the Suprascapular Notch in Patients with Arthroscopic Rotator Cuff Repair

Background

The morphology of the suprascapular notch (SSN) and the ossification of the superior transverse suprascapular ligament (STSL) are risk factors for injury of the suprascapular nerve (SN) during arthroscopic shoulder procedures. The purpose of the current study was to compare preoperative clinical and radiologic characteristics between patients with and without STSL ossification and to evaluate SSN morphology in patients who underwent arthroscopic rotator cuff repair using a 3-dimensional (3D) reconstructed model.

Methods

Patients who underwent arthroscopic rotator cuff repair and were given a computed tomography (CT) scan from March 2018 to August 2019 were included in this study. Patients were divided into 2 groups: those without STSL ossification (group I) and those with STSL ossification (group II). Tear size of the rotator cuff and fatty infiltration of rotator cuff muscles were assessed in preoperative magnetic resonance imaging. The morphology of the SSN was classified following Rengachary's classification. The transverse and vertical diameters of the SSN and the distances from anatomical landmarks to the STSL were measured. All measurements were completed using a 3D CT reconstructed scapula model.

Results

A total of 200 patients were included in this study. One hundred seventy-eight patients (89.0%) without STSL ossification were included in group I, and 22 patients (11.0%) with STSL ossification were included in group II. Group II showed a significantly advanced age (61.0 ± 7.4 vs. 71.0 ± 7.3 years, p < 0.001) and a shorter transverse diameter of SSN (10.7 ± 3.1 mm vs. 6.1 ± 3.7 mm, p < 0.001) than group I. In the logistic regression analysis, age was an independent prognostic factor for STSL ossification (odds ratio, 1.201; 95% confidence interval, 1.112-1.296; p < 0.001). Patients in type VI showed significantly shorter transverse diameters than other types (p < 0.001). The patient with type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than those with other types (p < 0.001).

Conclusions

In the 3D morphological analysis, age was the independent factor associated with STSL ossification in patients who underwent arthroscopic rotator cuff repair. Type VI showed significantly shorter transverse diameters than other types. Type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than other types.

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.

Interobserver and Intraobserver Variability of Four Suprascapular Notch Classification Systems

INTRODUCTION

Knowledge of the morphology of the suprascapular notch is clinically beneficial in patients with suspected suprascapular nerve compression or palsy. Several classification systems have been proposed for the morphological classification of the suprascapular notch and its several anatomical variations. The purpose of this study was to evaluate the inter- and intraobserver reliability of four different classification systems for suprascapular notch typing analysing shoulder computed tomography (CT) scans.

METHODS

Shoulder CT scans from 109 subjects (71.5% males) were examined by three raters of various experience levels, one senior, one experienced, and one junior orthopaedic surgeon. The CT scans were evaluated quantitatively and qualitatively and the suprascapular notch was classified according to four classification systems at two separate timepoints, four weeks apart. To determine consistency among the same or different raters, the Kappa statistic was performed and intrarater reliability for each rater between the first and the second evaluation was assessed using Cohen's kappa. Reliability across all raters at each timepoint was assessed using the Fleiss kappa.

RESULTS

Agreement was almost perfect for all the classification systems and amongst all raters, regardless of their experience level. There were no significant differences between the raters on any of the evaluations. The overall interobserver agreement for all classifications was almost perfect.

CONCLUSION

The four suprascapular notch classification systems are reliable, and the rater's experience level has no impact on the evaluation.

Suprascapular notch morphometric study

Relevance. The suprascapular notch is one of the most crucial areas of the scapula from a clinical standpoint. Aside from its anatomical relevance, the suprascapular notch type may also have some clinical implications for suprascapular nerve entrapment. Aim of the study was the determination of the different dimensions of the suprascapular notch based on the maximum depth (MD) and superior transverse diameter (STD), as well as the clinical relation between those dimensions and suprascapular nerve entrapment. Materials and Methods. The study’s materials were 100 unknown dry human scapulae from the from the anatomy department of the Mahatma Gandhi Medical College, Sitapura, Jaipur, Rajasthan. Each scapula was studied for suprascapular notch. From each of the scapulae, maximum depth and superior transverse diameter were determined. Fifty were from right side and Fifty were from left side. Different types of suprascapular notches were observed based on maximum depth and superior transverse diameter. Results and Discussion. In this study, the overall percentage distribution frequency of the suprascapular notch in 100 scapulae is MD STD (25 %), MD = STD (0 %), STD MD (60 %) and SSN Absent (15 %) respectively. The most common SSN type is STD MD (60 %) type and least common SSN type is MD = STD (0 %) type. Conclusion. Morphological examination of the scapular notch reveals a common site of nerve compression and also demonstrates the surgical importance of the scapular nerve during shoulder surgery.

Morphological and Morphometric study of suprascapular notch

Variation in the morphology of suprascapular notch is associated with suprascapular nerve entrapment neuropathy. So, the knowledge about different shapes of suprascapular notch is important for clinicians in understanding the source of the entrapment syndrome. The Shapes of suprascapular notch are of five in types - Deep U Shaped, shallow U Shaped, J Shaped, V Shaped & indented shaped. Deep U shape is most common & Indented is least common type of suprascapular notch. Suprascapular notch is semicircular in shape, situated in the superior border of the scapula just below the base of the coracoid process. Suprascapular notch is converted to the foramen by the attachment of the suprascapular ligament. Suprascapular vessels passes above the ligament & Suprascapular nerve passes below the ligament. In present study morphological data were obtained and classify the suprascapular notch according to their shape. Present study was conducted on 70 dry human scapulae of both sides with unknown age & sex. This study was conducted in the Department of Anatomy, Hind Institute of Medical Sciences, Barabanki. In the Present study Anatomical variation were found in suprascapular notch which included shape, partial & complete ossification of superior transverse ligament. 

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.

Morphometric Study of Suprascapular Notch and Its Safe Zone in Indian Population

Objectives: The suprascapular notch is located on the lateral part of the superior border of the scapula. The anatomical variation of the notch is considered as one of the causes of suprascapular nerve entrapment. In the present study, we tried to evaluate the morphology and morphometry of the suprascapular notch of Indian human dry scapulae and to compare it with scapula morphometry, which is essential to understand and treat different causes of suprascapular nerve entrapment and to obtain a safe zone, which would be useful to avoid iatrogenic nerve lesion during open arthroscopic surgeries and help in designing implants for the shoulder joint. Methods:This is an observational study, with a total of 200 human dry scapulae being observed, examined and studied in detail. The type of suprascapular notch was noted as per the description given by Rengachary et al. Digital Vernier Caliper was used for classical osteometric measurements of suprascapular notch parameters, posterior limit and posterosuperior limit of safe zone along with length and width of scapulae. A statistical data analysis was done. Results:Out of the 200,scapulae examined by us, 172 (86%) showed the presence of suprascapular notch, while nine (4.5%) showed partial ossification and 19 (9.5%) complete ossification. Six types of suprascapular notches were observed: type I,51 (25.5%); type II 45 (22.5%); type III 64 (32%); type IV 11 (5.5%); type V 9 (4.5%), and type VI 20 (10%). Type III notch was more prevalent. The study showed a moderate positive linear correlation between the width of the scapula and the safe zone of type III notch, respectively. Conclusion: Anatomical knowledge about the types of suprascapular notch and measurements is very helpful in the diagnosis and management of cases with shoulder pain due to suprascapular nerve entrapment and also while administering suprascapular nerve blocks for surgeries involving the shoulder region. Safe zone distances are very important for avoiding iatrogenic suprascapular nerve injuries during shoulder surgical procedures.

Anatomical Variations of the Suprascapular Notch and its Importance in Suprascapular Entrapment Neuropathy

Background: Anatomical knowledge about the suprascapular notch is very important in understanding the risk of suprascapular nerve entrapment syndrome. Suprascapular nerve injuries have become commonly recognized as a cause of shoulder pain and dysfunction. This study aimed to describe the morphometrical influence of the suprascapular notch on the course of the suprascapular nerve. Method: A total of 138 dry human scapulae of both sides of the unknown sex were used. Four measurements were defined and collected for every suprascapular notch: maximum depth (MD), superior transverse diameter (STD), middle transverse diameter (MTD), and total circumferential diameter (TCD). Result: In the present study we found different shapes of suprascapular notches. Out of 138 scapulae, 67 (48.55%) had U-shaped notch, 29 (21.01%) V-shaped notch and 14 (10.14%) J-shaped notch. Nine (6.52%) scapulae had incomplete notch. Two (1.44%) scapulae had large double foramen. Six (4.34%) scapulae had complete suprascapular notch. In seven (5.07%) scapulae, the notch was absent. Interestingly, in two (1.44%) scapulae, we found a W-shaped notch. This observation was unique and not reported anywhere in the literature before. Conclusion: Anatomical knowledge about the morphology of the suprascapular notch is of extreme importance for clinicians, radiologists, neurosurgeons, and orthopedic surgeons in making a proper diagnosis and for planning the surgical procedures of the shoulder region.

Morphometric study of suprascapular notch and scapular dimensions in Ugandan dry scapulae with specific reference to the incidence of completely ossified superior transverse scapular ligament

BACKGROUND

Understanding of suprascapular notch (SSN) anatomy and relationship with scapular dimensions are vital in diagnosis, prevention, and assessment of suprascapular nerve entrapment syndrome. The study aimed to assess morphometry of suprascapular notch and scapular dimensions in Ugandan dry scapulae with specific reference to scapulae with completely ossified superior transverse scapular ligaments.

METHODS

This was a cross-sectional analytical study conducted on 50 Ugandan dry scapulae. SSN types and prevalence of completely ossified superior transverse scapular ligament among dry scapulae were quantified and compared with previous data. Scapular dimensions were assessed by measuring scapular length (A), scapular width (B), glenoid length (C), and glenoid width (D). One-way ANOVA was used to compare scapular dimensions of scapulae with different SSN types, and Spearman's correlation coefficient was used to evaluate the correlation coefficient of scapular dimensions amongst groups.

RESULTS

Superior transverse scapular ligament (STSL) was completely ossified in 8% of cases. There was no significant (P > 0.05) difference between scapular dimensions of scapulae with completely ossified STSL compared to scapulae with other SSN types. Scapulae with completely ossified STSL showed strong negative (r = - 0.89137, r = - 0.877) correlations for its A, B respectively compared against D, this finding was not true to scapulae of other SSN types. Also, there were strong positive or negative (r > 0.7, r > - 0.7) correlations: for A, types I and III compared to type VI; for B, types I, III compared to VI; for C, type IV and VI; and for D, type III and VI.

CONCLUSIONS

The prevalence of completely ossified STSL is moderately high in the Ugandan population. Characteristics of the scapula (scapular dimensions) are not 'vital' but rather important or relevant for shoulder pathology with specific reference to suprascapular nerve entrapment syndrome due to completely ossified superior transverse scapular ligaments. Further correlation analyses of scapular dimensions of different SSN types in different populations are important.

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.

Echo-guided invasive pain therapy: indications and limitations

PURPOSE OF REVIEW

The purposes of this review are to summarize the advantages and limitations of ultrasound-guided pain interventions, and to illustrate those interventions with peripheral, axial and musculoskeletal pain procedures.

RECENT FINDINGS

With the capability of locating the interfascial plane, ultrasonography has led to the emergence of a series of plane blocks for the thoracoabdominal region in the recent decade.Ultrasonography for musculoskeletal procedures has been of growing interest because of the major advantage of direct visualization and scanning of various soft tissues and real-time spread in the injectate, thereby enhancing precision and efficacy, reducing risk of trauma and avoidance of radiation. For spine and intra-articular structures, ultrasonography is complicated by the bony shadow artefact and often deep location of the structure, making acquisition of ultrasound image challenging. Despite these difficulties, there is growing interest in applying ultrasonography for cervical spine and sacroiliac joint procedures.

SUMMARY

Pain intervention under ultrasound guidance is particularly valuable in peripheral and musculoskeletal procedures. There is growing interest of its application in cervical spine and sacroiliac joint. More outcome studies are required in the future to make ultrasound-guided pain intervention as the established procedure.

Classification of the superior angle of the scapula and its correlation with the suprascapular notch: a study on 303 scapulas

PURPOSE

The aims of this study had been to classify the superior angle of the scapula based on morphological features, and to investigate its correlation with the suprascapular notch.

METHODS

303 samples of Chinese dried scapular specimens were collected from the Department of anatomy, Southwest Medical University. According to the anatomical morphological characteristics of the superior angle of the scapula, the morphological classification was performed to explore its correlation with the suprascapular notch (SSN).

RESULTS

The superior angle of the scapula was classified into three types (Hilly shape, Mountain Peak shape and Chimney shape). There were 143 cases of Hilly shape (47.20%), 144 cases of Mountain shape (47.52%), and 16 cases of Chimney shape (5.28%). The angle of Hilly shape (93.36° ± 7.76°) was significantly larger than the Mountain Peak shape (86.60° ± 6.61°) and the Chimney shape (86.22° ± 7.20°), and the difference was statistically significant (P < 0.05). The type I-III of Rengachary's classification to SSN was low risk of suprascapular nerve entrapment, while the type IV-VI was high risk of suprascapular nerve entrapment. Compared with the Mountain Peak shape and the Chimney shape, the Hilly shape corresponds to more types I-III of suprascapular notch but to fewer types IV-VI (P < 0.05).

CONCLUSIONS

The superior angle of the scapula was divided into three types: Hilly shape (47.20%), Mountain Peak shape (47.52%) and Chimney shape (5.28%). The Mountain Peak shape might be more likely to result in inability of the levator muscle with acute or chronic overload mechanisms, and the risk of suprascapular nerve entrapment in Mountain peak shape was higher than that of Hilly shape. And, it might have a potential effect on neck pain.

The prevalence and morphometric analysis of ossified superior transverse scapular ligaments in patients with rotator cuff tears

BACKGROUND

The prevalence of ossified superior transverse scapular ligaments (OSTSLs) in rotator cuff tears (RCTs) has not yet been determined. The purposes of this study were to evaluate the prevalence of OSTSLs in RCTs and to investigate the correlation between OSTSL morphology and supraspinatus muscle atrophy.

METHODS

We analyzed a total of 213 patients with RCTs for whom 3-dimensional (3D) computed tomography (CT) and magnetic resonance imaging were performed prior to arthroscopic procedures. The mean age of the patients was 59.73 ± 8.43 years, and 103 patients were men. OSTSLs were identified based on 3D CT findings. The correlations between OSTSLs and age, sex, and RCT size were analyzed. The horizontal and vertical diameters, area, and circumference of the suprascapular foramen were measured. By use of the occupation ratio calculated from magnetic resonance imaging results, supraspinatus muscle atrophy was evaluated.

RESULTS

Of 213 patients with RCTs, 22 (10.3%) had OSTSLs. OSTSLs were found at a rate of 15.5% (16 of 103) in men, higher than that in women (P = .016). The rate of OSTSLs increased with age (P = .003). RCT size was not correlated with the prevalence of OSTSLs. As the horizontal diameter and circumference of the suprascapular foramen increased, muscle atrophy progressed (P = .001 and P = .046, respectively).

CONCLUSION

One of ten patients with RCTs had OSTSLs; the rate of OSTSLs was higher among men and increased with age. For patients with RCTs preparing to undergo arthroscopic superior transverse ligament resection, preoperatively identifying OSTSLs through 3D CT would be useful for the resection.

Nerves Around the Shoulder: What the Radiologist Should Know?

Peripheral neuropathies of the shoulder are common and could be related to traumatic injury, shoulder surgery, infection or tumour but usually they result from an entrapment syndrome. Imaging plays an important role to detect the underlying causes, to assess the precise topography and the severity of nerve damage. The key points concerning the imaging of nerve entrapment syndrome are the knowledge of the particular topography of the injured nerve, and the morphology as well signal modifications of the corresponding muscles. Magnetic Resonance Imaging best shows these findings, although Ultrasounds and Computed Tomography sometimes allow the diagnosis of neuropathy.

Intraoperative Fluoroscopic Imaging for Suprascapular Nerve Localization During Spinal Accessory Nerve to Suprascapular Nerve Transfer

Distal fiber transfer of the spinal accessory nerve (SAN) to the suprascapular nerve (SSN) has been well described as an effective means to regain shoulder external rotation following upper trunk brachial plexus injuries. Both supine and prone positioning techniques have been described with comparable success. Whereas the posterior technique allows for sufficient distal length on the SAN for effective neurotization of the infraclavicular brachial plexus and SSN both proximal and distal to the suprascapular ligament, localization of the SSN within the suprascapular notch can be challenging and time intensive, especially in the obese patient. The use of intraoperative C-arm fluoroscopy is presented as a viable method for more exact suprascapular notch identification during dissection of the SSN.

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.

Unusual morphology of scapulae: incidence and dimensions of ossified ligaments and supraspinous bony tunnels for clinical consideration

INTRODUCTION

Knowledge of morphological variations of the suprascapular region is important in the management of entrapment neuropathy and interventional procedures. The objective of this study was to collect data on the morphological features and dimensions of ossified ligaments and unusual bony tunnels of scapulae from a North Indian population.

METHODS

A total of 268 adult human scapulae of unknown gender were obtained from the bone bank of the Department of Anatomy, Dayanand Medical College and Hospital, Ludhiana, Punjab, India. The scapulae were evaluated for the incidence of ossified superior transverse scapular ligaments (STSLs), ossified inferior transverse scapular ligaments (ITSLs) and bony tunnels (i.e. the bony canal between the suprascapular notch and spinoglenoid notch), found along the course of the suprascapular nerve (SSN). The dimensions of these structures were measured and noted down. Ossified STSLs were classified based on their shape (i.e. fan- or band-shaped) and the dimensions of the ossified suprascapular openings (SSOs) were measured.

RESULTS

Ossified STSLs were present in 26 (9.7%) scapulae. Among the 26 scapulae, 16 (61.5%) were fan-shaped (mean area of SSO 16.6 mm(2)) and 10 (38.5%) were band-shaped (mean area of SSO 34.2 mm(2)). Bony tunnels were observed in 2 (0.75%) specimens, while an ossified ITSL was observed in 1 (0.37%) specimen.

CONCLUSION

The data obtained in the present study augments the reference literature for SSN decompression and the existing anatomical databases, especially those on Indian populations. This data is useful to clinicians, radiologists and orthopaedic surgeons.

Anterior Coracoscapular Ligament as a Factor Predisposing to or Protective for Suprascapular Neuropathy

Suprascapular neuropathy is a pathology caused by injury or compression of the suprascapular nerve. As the nerve runs from the anterior to posterior side of the scapula, the hot point where it is most susceptible to both injury and compression is the suprascapular notch. A literature search reveals several potential predisposing morphological factors in this area. However the most recent reports indicate that the structures at the suprascapular notch region may also prevent nerve injury and compression. The role of the anterior coracoscapular ligament (ACSL) remains unclear. While some studies indicate that it may predispose to suprascapular neuropathy, the newest study proposes a protective function. The aim of the article was to review the function of the anterior coracoscapular ligament in the light of the most recent studies. An understanding of the role of the ligament is essential for arthroscopic and other surgical procedures of this area in order to avoid iatrogenic injury of the suprascapular nerve.

Suprascapular notch morphology in the pediatric population: a computed tomography study

Suprascapular notch is characterized by variable morphology. However, its development is not well studied. We hypothesize that it proceeds postnatally. Thus, the aim of this research was to characterize the morphology of the suprascapular notch in a pediatric population based on computed tomography. A retrospective analysis was performed of 291 chest computed tomography examinations of patients under 18 years old taken following other clinical indications. The inclusion criteria were as follows: both scapulae encompassed in a field of view; no artifacts; no pathologies concerning the scapulae. Based on visual assessment and measurements, the suprascapular notch was classified according to a fivefold classification (type I, deeper than wider; type II, equally deep and wide; type III, wider than deeper; type IV, bony foramen; type V, discreet notch). In all, 173 examinations were included (60 females and 113 males). The most common suprascapular notch types were discreet notch (type V, 225 scapulae; 65.0 %) and type III (114 scapulae; 32.9 %). Children with type V suprascapular notch were significantly younger than children with other types (26.1 ± 42.4 months vs. 111.2 ± 66.7 months; p < 0.05). In types I–III, a positive correlation was found between age and dimensions of the suprascapular notch (p < 0.05). This study provides the first description of the suprascapular notch in a pediatric population based on computed tomography. It confirms that morphology of the suprascapular notch undergoes postnatal development.

The suprascapular notch narrows with aging: a preliminary solution of the old conjecture based on a 3D-CT evaluation

PURPOSE

The purpose of this study was to describe the morphology of the suprascapular notch in terms of age distribution. We hypothesized that the notch narrows with aging.

METHODS

Seven hundred and sixty consecutive patients (465 men and 295 women) scheduled for a shoulder surgery were retrospectively reviewed. A 3D-CT of the shoulder was taken to evaluate the shape of the notch according to the Rengachary classification. The six types of Rengachary classification were arranged into three major categories according to transverse scapular ligament ossification and notch size as follows: the wide notch (type 1 and type 2); the narrow notch (type 3 and type 4); and the ossified notch (type 5 and type 6). Comparisons between categories were done with a one-way analysis of variance.

RESULTS

There was a statistically significant difference among the three categories (P < .01): the narrow notch group (n = 442, 63.4 ± 12.8 years) and the ossified notch group (n = 66, 65.9 ± 10.6 years) were significantly older than the wide notch group (n = 252, 57.5 ± 17.8 years), respectively. In patients with Rengachary type 5 shoulders, ossification was dominant on the medial side of the notch in 37 of 39 shoulders (92.3 %).

CONCLUSION

The current study showed that morphological changes of the scapular notch are related to aging. The narrow notch and the ossified notch are seemed to be developed from the wide notch in terms of the ossification starting from the medial side.

Morphometry and variations of the human suprascapular notch

AIM

The present study proposes a simple method to study variations in shape and dimensions of suprascapular notch, to classify different types and subtypes of notch and to measure the thickness of superior transverse scapular bar (ossified superior transverse ligament of scapula).

MATERIAL AND METHODS

Seven hundred and twenty-eight dried scapulae were observed, examined and studied in detail. Scapulae with suprascapular notch, with suprascapular foramen having varying degree of ossification in the form of transverse scapular bar were included in the present study. Measurements of suprascapular notch and superior transverse scapular bar were taken with the help of digital vernier calliper and recorded in millimetres. The superior transverse diameter, inferior transverse diameter, depth, maximum thickness of suprascapular notch and thickness at lateral and medial end of transverse scapular bar, mean thickness of superior transverse scapular bar were recorded. The data was analyzed statistically.

OBSERVATIONS AND RESULTS

We observed five types of notch in scapulae, type I: without a discrete notch (ill defined), 25 (3.43%); type II: a "V" shaped notch, 192 (26.37%); type III: "U" shaped notch, 383 (52.60%); type IV: inverted "V" shaped notch, 28 (3.84%); type V with absent suprascapular notch: 6 (0.82%). Type II and type III were again subclassified into subtypes (a, b, c and d) on the basis of depth of notch. Scapulae with superior transverse scapular bar (n=94, 12.91%) were classified according to variation in mean thickness of transverse scapular bar (MTSB).

CONCLUSION

This study will help clinicians to correlate suprascapular nerve entrapment with a specific type of suprascapular notch and notch with ossified transverse scapular ligament.

Anatomic observation of the running space of the suprascapular nerve at the suprascapular notch in the same direction as the nerve

PURPOSE

The configuration of suprascapular notch was previously analysed from the anteroposterior viewing. However, the approach direction of the suprascapular nerve (SSN) to the inlet of the suprascapular notch is consistently craniocaudal and mediolateral. We propose a new method to observe the suprascapular notch according to the running course of the SSN. We reviewed the anatomic characteristics of the suprascapular notch in relation to the nerve.

METHODS

In 30 formalin-fixed cadaveric shoulders, the morphology of the suprascapular notch and the attachments of the superior transverse scapular ligament (STSL) were examined from both the anteroposterior and the nerve approach direction. The dimensions of the opening of the SSN passage were measured.

RESULTS

By observing from the nerve approach direction, the inlet of the suprascapular notch was recognized to be a space-bordered by the medial wall of the coracoid process, the deep fascia of subscapularis, and the STSL. The STSL formed a sheet-like structure, which ran parallel to the nerve and also to the deep fascia of subscapularis. The attachment of the ligament to the coracoid process was located at the posteromedial corner rather than the medial side.

CONCLUSION

Based on the present study, the space between the STSL and deep fascia of the subscapularis formed the space for the nerve to run through. As a clinical implication, this new method to assess the suprascapular notch in the nerve approach direction might develop the imaging techniques for evaluation of SSN entrapment.

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.

What is the function of the anterior coracoscapular ligament? - a morphological study on the newest potential risk factor for suprascapular nerve entrapment

BACKGROUND

The suprascapular notch (SSN) is the most common site of suprascapular nerve neuropathy, which may be brought on by the presence of a deep, narrow SSN and structures restricting the space for the nerve. The anterior coracoscapular ligament (ACSL) is a fibrous band extending on the anterior side of the suprascapular notch. As it may tighten the osteo-fibrous tunnel for the nerve, it has been proposed as a new anatomical risk factor in its entrapment. However, this structure occurs in up to 60% of patients, many of whom do not demonstrate any nerve injury. The aim of this work is to evaluate the association between the occurrence of the ACSL and SSN morphology.

MATERIALS AND METHODS

The suprascapular notch region was dissected in 100 formalin-fixed, cadaveric shoulders. The ACSL (if present) and the SSN were assigned to a classification based on their morphology and diameters. Statistical analysis was performed.

RESULTS

The ACSL was present in 52 scapulae (52%) and in all cases, the suprascapular nerve travelled superior to the ACSL. Mechanically relevant types of ACSL were found to occur significantly more often when deeper notches were present (p=0.0018).

CONCLUSIONS

The mechanically efficient ACSL is more common in deep and narrow SSNs, which are associated with suprascapular nerve neuropathy. Thus, by supporting the nerve, the ACSL can protect against its injury.

Suprascapular notch variations: a 3DCT study

BACKGROUND

Although cadaveric studies have revealed suprascapular notch shape variations, few have investigated the association between suprascapular notch variation and age or gender. The purpose of this study was to investigate suprascapular notch shape variations by use of three-dimensional computed tomography (3DCT) and to determine if there was any association with age or gender.

METHODS

Three-dimensional CT images of 762 shoulders of 762 patients were analyzed in this study. Participants comprised 404 men and 358 women, with an average age of 58.2 ± 19.1 years. Suprascapular notch shape variations were classified into six types on the basis of Rengachary's classification.

RESULTS

Of the total study population, 11.4% were classified as type I, 23.5% as type II, 30.1% as type III, 14.8% as type IV, 15.9% as type V, and 4.3% as type VI. Average age was 56.5 ± 20.5 years for type I, 57.0 ± 19.5 years for type II, 55.5 ± 20.0 years for type III, 56.4 ± 18.5 years for type IV, 65.5 ± 14.4 years for type V, and 68.0 ± 13.4 years for type VI. Statistically significant age differences were found between types I-IV and V, between types I-IV and VI, and between the non-ossification group (types I-IV) and the ossification group (types V and VI). Male-to-female ratio among each type, and between the non-ossification group and the ossification group, were not statistically significantly different.

CONCLUSIONS

Our results suggest that transverse scapular ligament ossification is associated with aging whereas individual variation explains differences among types I, II, III, and IV. Three-dimensional CT provides useful information for arthroscopic resection of the transverse scapular ligament, when the wide variety of suprascapular notch shape variations is considered.

LEVEL OF EVIDENCE

Level IV.

Suprascapular Notch asymmetry: a study on 311 patients

The most important risk factor of suprascapular nerve entrapment is probably the shape of the suprascapular notch (SSN). The aim of the study was to perform a radiological study of the symmetry of SSN. Included in the study were 311 patients (137 women and 174 men) who underwent standard computed tomography investigation of the chest. A total of 622 computed tomography scans of scapulae were retrospectively analyzed to classify suprascapular notches into five types. Suprascapular notch was recognized as a symmetrical feature in 53.45% of the patients. Symmetry was more frequently seen in females (54.0% versus 52.9%), but not to any significant degree (P = 0.8413). Type III was the most commonly noted symmetrical feature (66.9%) and type II was less common (0.6%). Type III was the most symmetrical type of suprascapular notch, occurring significantly more often as a symmetrical feature in comparison with type I (P < 0.0001), type II (P = 0.00137), or type IV (P = 0.001). Our investigation did not show that the suprascapular notch is a symmetrical feature. However, symmetry was recognized more frequently in the case of type III SSN. No significant differences in symmetry were found with regard to sex.

Morphological and radiological study of ossified superior transverse scapular ligament as potential risk factor of suprascapular nerve entrapment

The suprascapular notch is covered superiorly by the superior transverse scapular ligament. This region is the most common place of suprascapular nerve entrapment formation. The study was performed on 812 specimens: 86 dry scapulae, 104 formalin-fixed cadaveric shoulders, and 622 computer topography scans of scapulae. In the cases with completely ossified superior transverse scapular ligament, the following measurements were performed: proximal and distal width of the bony bridge, middle transverse and vertical diameter of the suprascapular foramen, and area of the suprascapular foramen. An ossified superior transverse scapular ligament was observed more often in men and in the right scapula. The mean age of the subjects with a completely ossified superior transverse scapular ligament was found to be similar than in those without ossification. The ossified band-shaped type of superior transverse scapular ligament was more common than the fan-shaped type and reduced the space below the ligament to a significantly greater degree. The ossified band-shaped type should be taken into consideration as a potential risk factor in the formation of suprascapular nerve entrapment. It could explain the comparable frequency of neuropathy in various populations throughout the world despite the significant differences between them in occurrence of ossified superior transverse scapular ligament.

Morphometric study of suprascapular notch in Indian dry scapulae with specific reference to the incidence of completely ossified superior transverse scapular ligament

BACKGROUND

The suprascapular notch, a depression on the lateral part of the superior border of the scapula, medial to the coracoid process, is bridged by the superior transverse scapular ligament, which is sometimes ossified and the foramen which is thus completed, transmits the suprascapular nerve to the supraspinatus fossa. Variations in the morphology of suprascapular notch have been identified as one of the causes of suprascapular nerve entrapment. Rengachary et al. classified this notch into six types, based on its shape.

AIM OF STUDY

To study morphological variations of suprascapular notch in Indian dry scapulae and to analyze the incidence of completely ossified superior transverse scapular ligament with other ethnic populations which have been cited earlier.

MATERIALS AND METHODS

A total of 400 human dry scapulae which were obtained from the Department of Anatomy of selected eight medical colleges were analyzed. The type of suprascapular notch was noted and it was recorded as per the description given by Rengachary et al. The results of the present study were compared with the results of previous authors in different populations.

RESULTS

In our study, out of 400 scapulae, 40 (10%), were identified to have completely ossified superior transverse scapular ligaments. The frequencies of various types of suprascapular notches were: Type I -20%, Type II -10%, Type III -52%, Type IV -4%, Type V -4%, Type VI -10%.

CONCLUSION

Since the suprascapular nerve entrapment syndrome might be caused by complete ossification of superior transverse scapular ligament with formation of suprascapular foramen and other morphometric variations of suprascapular notch, the knowledge on such variations is essential for clinicians, for making a proper diagnosis and for planning the most suitable surgical intervention.

Suprascapular nerve entrapment due to a stenotic foramen: a variant of the suprascapular notch

Suprascapular nerve (SSN) entrapment is an uncommon cause of posterior shoulder pain. Entrapment can be relieved arthroscopically in some cases.

Anatomical study of the suprascapular notch: quantitative analysis and clinical considerations for suprascapular nerve entrapment

INTRODUCTION

Detailed anatomical knowledge of the suprascapular notch (SSN) is important for the management of entrapment neuropathy and interventional procedures. The objective of the present study was to collect data on the morphological features and anatomical variations of the SSN in an Indian population.

METHODS

We studied 268 human scapulae of unknown sex (126 right-sided, 142 left-sided) taken from the Department of Anatomy, Dayanand Medical College and Hospital, India. SSNs were classified as either type I, II, III, IV or V, based on the shape of the inferior border of the incisura, and comparison of the SSN's vertical and transverse diameters. The shape of the SSN (i.e V- or U-shaped), if present, was also recorded.

RESULTS

Type II SSN was the most common (50.00%), followed by type I, type IV and type III (32.46%, 9.70% and 7.84%, respectively). For right-sided type II SSNs, the transverse and vertical diameters were 9.1 ± 3.2 mm and 5.2 ± 1.9 mm, respectively, while those for left-sided type ll SSNs were 9.2 ± 2.4 mm and 5.1 ± 1.8 mm, respectively. Generally, the transverse diameter of type II SSN was found to be greater than that of type III SSN. The incidence of U-shaped SSN was 51.49%, while that of V-shaped SSN was 2.99%.

CONCLUSION

This study of the morphometrical characteristics and anatomical variations of SSN provides an anatomical database of SSN in the Indian context. This database will be of use in surgical procedures, as the information can be used to ensure adequate access to and complete decompression of the suprascapular nerve.

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.

A proposal for classification of the superior transverse scapular ligament: variable morphology and its potential influence on suprascapular nerve entrapment

BACKGROUND

The suprascapular region is the most common site of suprascapular nerve entrapment. The aim of the present study was to determine the morphologic variation of the superior transverse scapular ligament (STSL) and measure the reduction in size of the suprascapular opening. Other structures that might be potentially significant during open and arthroscopic procedures in this region are also described.

MATERIALS AND METHODS

The study used 86 randomized formalin-fixed human cadaveric shoulders. After dissection of the suprascapular region, the following measurements were defined and collected for every STSL: length, proximal width, distal width, and thickness at the proximal and distal ends. Measurements were also taken of the area of the suprascapular opening (aSSO) and the middle width of the suprascapular opening (mwSSO).

RESULTS

Three types of STSL may be distinguished: a fan-shaped type (54.6%), a band-shaped type (41.9%), and a bifid type (3.5%). Statistically significant differences between the specimens with fan-shaped and band-shaped types of STSL were observed in aSSO and mwSSO of the suprascapular opening. Anterior coracoscapular ligaments (ACSL) were present in 44 of 86 shoulders. The aSSO and mwSSO were smaller in specimens with an ACSL than in those without; however, this difference was only significant in the band-shaped type of STSL.

CONCLUSION

Knowledge of the morphologic variations of STSL presented in this study is important for better understanding the possible anatomic conditions that can promote suprascapular nerve entrapment and should be taken into particular consideration during surgical and arthroscopic procedures around the suprascapular notch.

Variation in morphology of suprascapular notch as a factor of suprascapular nerve entrapment

PURPOSE

The shape and size of the suprascapular notch (SSN) is one of the most important risk factors in suprascapular nerve entrapment. The aim of the study was to perform a morphological study of SSN variations.

METHODS

A total of 616 computer tomography scans of scapulae were retrospectively analysed in 308 patients. The examination focused on the suprascapular region. The type of suprascapular notch was determined by using a classification based on three geometrical measurements: maximal depth (MD), superior (STD) and middle (MTD) transverse diameters.

RESULTS

In the scans, five types of SSN were noted. In type I (24.18%) maximal depth was greater than superior transverse diameter. Type II (1.95%) has equal MD, STD and MTD. In type III (56.16%) the superior transverse diameter was greater than the maximal depth. Scapulae with bony foramen were classified as type IV (4.72%). In type V a discrete notch (12.99 %) was found. Additionally, types I and III were divided into three subtypes: A, B and C. The frequency of type I and IV was lower in females than in males, but type III was more common in females than males. Distribution of other types of SSN in both groups was similar.

CONCLUSION

Knowledge of the anatomical variations of the suprascapular notch described in this study should be helpful in endoscopic and open procedures of the suprascapular region and also may increase the safety of operative decompression of the suprascapular nerve.

Morphometry of the suprascapular notch: correlation with scapular dimensions and clinical relevance

Background

Better knowledge of the suprascapular notch anatomy may help to prevent and to assess more accurately suprascapular nerve entrapment syndrome. Our purposes were to verify the reliability of the existing data, to assess the differences between the two genders, to verify the correlation between the dimensions of the scapula and the suprascapular notch, and to investigate the relationship between the suprascapular notch and the postero-superior limit of the safe zone for the suprascapular nerve.

Methods

We examined 500 dried scapulae, measuring seven distances related to the scapular body and suprascapular notch; they were also catalogued according to gender, age and side. Suprascapular notch was classified in accordance with Rengachary’s method. For each class, we also took into consideration the width/depth ratio. Furthermore, Pearson's correlation was calculated.

Results

The frequencies were: Type I 12.4%, Type II 19.8%, Type III 22.8%, Type IV 31.1%, Type V 10.2%, Type VI 3.6%. Width and depth did not demonstrate a statistical significant difference when analyzed according to gender and side; however, a significant difference was found between the depth means elaborated according to median age (73 y.o.). Correlation indexes were weak or not statistically significant. The differences among the postero-superior limits of the safe zone in the six types of notches was not statistically significant.

Conclusions

Patient’s characteristics (gender, age and scapular dimensions) are not related to the characteristics of the suprascapular notch (dimensions and Type); our data suggest that the entrapment syndrome is more likely to be associated with a Type III notch because of its specific features.

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.

Ultrasound-guided pain interventions - a review of techniques for peripheral nerves

Ultrasound has emerged to become a commonly used modality in the performance of chronic pain interventions. It allows direct visualization of tissue structure while allowing real time guidance of needle placement and medication administration. Ultrasound is a relatively affordable imaging tool and does not subject the practitioner or patient to radiation exposure. This review focuses on the anatomy and sonoanatomy of peripheral non-axial structures commonly involved in chronic pain conditions including the stellate ganglion, suprascapular, ilioinguinal, iliohypogastric, genitofemoral and lateral femoral cutaneous nerves. Additionally, the review discusses ultrasound guided intervention techniques applicable to these structures.

Sexual dimorphism of the suprascapular notch - morphometric study

INTRODUCTION

The concept of the study was to compare the morphometry of the suprascapular notch (SSN) in females and males because its size and shape may be a factor in suprascapular nerve entrapment.

MATERIAL AND METHODS

The measurements of 81 scapulae included morphological length and width, maximal width and length projection of the scapular spine, and width and length of the glenoid cavity. The width-length scapular and glenoid cavity indices were calculated. In addition to standard anthropometric measurements three other dimensions were defined and collected for every SSN: maximal depth (MD), superior (STD) and middle (MTD) transverse diameters.

RESULTS

The analysis of the measurements allowed us to distinguish five types of SSN. Type I (26%) had longer maximal depth than superior transverse diameter. Type II (3%) had equal MD, STD and MTD. In type III (57.6%) superior transverse diameter was longer than maximal depth. In type IV (7.4%) a bony foramen was present. Type V (6%) was without a discrete notch. Types I and III were divided into two subtypes: A (MTD was longer than STD) and B (MTD < STD). Distribution of the suprascapular notch types in both sexes was similar. However, MD, STD and MTD were significantly higher in males. The superior transverse suprascapular ligament was completely and partially ossified in 7.4% and 24.7% respectively.

CONCLUSIONS

The presented classification of the suprascapular notch is simple, easy to use, and based on specific geometric parameters which allow one to clearly distinguish five types of these structures. All dimensions of SSN were significantly higher in males than in females.

A study on the morphology of the suprascapular notch and its distance from the glenoid cavity

INTRODUCTION

A suprascapular nerve entrapment can occur at the suprascapular notch or at the spinoglenoid notch. So, the size and shape of the suprascapular notch are associated with suprascapular entrapment neuropathy as well as with an injury to the suprascapular nerve in arthroscopic procedures. The knowledge on the variations along the course of the nerve is important in understanding the source of the entrapment syndrome.

MATERIAL AND METHODS

The present study was carried out on 104 scapulae which were obtained from the Department of Anatomy, NRI Medical College and from other nearby medical colleges. The suprascapular notches in the scapulae were classified, based on the descriptions of Rengachary et al and Ticker et al. The distance between the suprascapular notch and the supraglenoid tubercle, and the distance between the posterior rim of the glenoid cavity and the medial wall of the spinoglenoid notch at the base of the scapular spine, were determined. The data were analyzed statistically.

RESULTS

Based on the Rengachary classification, the type III notch was more common. The suprascapular foramen was observed in 2 scapulae. In 56.73% scapulae, the superior transverse diameter was greater than the maximum depth. The U shaped notch (69.23%) was more common. 2.88% and 8.65% scapulae fell short of the mentioned respective safe zone distances from the margin of the glenoid cavity.

CONCLUSION

Such studies may be useful in understanding the role of the notch in causing nerve entrapment and to prevent iatrogenic nerve injuries while posterior approaches are made to the shoulder joint.

Coexistence of the suprascapular notch and the suprascapular foramen--a rare anatomical variation and a new hypothesis on its formation based on anatomical and radiological studies

The suprascapular notch is the most common site of suprascapular nerve entrapment, which can manifest in disability and pain of the upper limb. Here, we present three cases of a very rare anatomical variation in the suprascapular region: the coexistence of the suprascapular notch and the suprascapular foramen. The variation was found during radiological and anatomical investigations. The suprascapular foramen was situated inferior to the suprascapular notch. A bony bridge lay between them, likely created by an ossified anterior coracoscapular ligament (ACSL). This anatomical variation probably increased the risk of suprascapular nerve entrapment by nerve irritation of the bony margins during passsage through the foramen and by a lack of the elasticity that the ACSL normally demonstrates. Also, a bony bridge passing through the middle part of the suprascapular notch reduces the space available for nerve passage (bony bridge decreases the space by about 36.5–38.6 %). One patient who underwent the radiological study had typical symptoms of suprascapular nerve entrapment. Based on his medical history and the presence of this rare variation of the suprascapular notch at the suprascapular region we suspect this neuropathy.

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.

Variations in bifid superior transverse scapular ligament as a possible factor of suprascapular entrapment: an anatomical study

PURPOSE

The suprascapular region is the most common place for suprascapular nerve entrapment. The purpose of this research was to investigate the influence of the superior transverse scapular ligament (STSL) on the reduced space for suprascapular nerve passage at the suprascapular notch. Additionally, we precisely described other structures that seem important during arthroscopic and open procedures in this region.

METHODS

The study was carried out on 96 formalin-fixed cadaveric shoulders. After dissection of the suprascapular region the superior transverse scapular ligament was visualised. Measurements of the ligaments and area of the opening for the passage of the suprascapular nerve were taken using two independent methods: MultiScanBase v.14.02 software and electronic digimatic caliper.

RESULTS

In three of 96 dissected shoulders (3.1 %), a bifid superior transverse scapular ligament was discovered. Morphologically, two subtypes of bifid STSL were distinguished. The first has medially separate superior and inferior bands and a common lateral attachment. In the second subtype, independent anterior and posterior parts are fixed to the lateral border of the suprascapular notch with a common medial attachment. Singular STSL in 93 of 96 shoulders was found. The mean area of the suprascapular opening in the specimens with singular STSL was larger than in the first subtype of bifid STSL and in the second subtype of bifid STSL with anterior coracoscapular ligament.

CONCLUSION

Knowledge of the variations of the superior transverse scapular ligament is important for better understanding of the possible anatomical conditions that can promote suprascapular nerve entrapment. Its morphology should also be taken into particular consideration during surgical and arthroscopic procedures.

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.

Suprascapular nerve block: a narrative review

Suprascapular nerve blockade (SSNB) is a simple and safe technique for providing relief from various types of shoulder pain, including rheumatologic disorders, cancer, and trauma pain, and postoperative pain due to shoulder arthroscopy. Posterior, superior, and anterior approaches may be used, the most common being the posterior. Recently, an ultrasound-guided approach has been described. In this review, the basic anatomy of the suprascapular nerve will be described. The different techniques of SSNB and indications for SSNB will be discussed. The complications of SSNB and outcomes of SSNB on the management of acute and chronic shoulder pain will be reviewed.