Suprascapular Notch Variations in Dry Human Scapulae: Implications for Suprascapular Nerve Entrapment

Introduction The suprascapular notch (SSN) is an important anatomical landmark along the upper border of the scapula, which allows the suprascapular nerve to pass through. Variations in the morphology of the SSN, particularly those associated with ossification of the superior transverse scapular ligament (STSL), are known to predispose individuals to suprascapular nerve entrapment. Knowledge of these variations is therefore essential for accurate diagnosis and safe surgical interventions around the shoulder region. Aim To study the morphological variations of the suprascapular notch in dry adult human scapulae. Materials and methods The present descriptive study was conducted on 70 dry adult human scapulae of unknown age and gender acquired from the osteology collection of the Anatomy Department, Lady Hardinge Medical College, New Delhi. Scapulae with damaged or deformed superior borders were excluded. The SSN of each specimen was carefully examined and classified into Types I-VI based on the modified Rengachary classification. The frequency and percentage distribution of each notch type were recorded. Statistical analysis was performed using SPSS by applying the Z-test for a single proportion for each type of suprascapular notch, statistical p value of less than 0.05 regarded as significant. Results Among the 70 scapulae studied, Type III suprascapular notch was the most common, observed in 40 (57.10%) specimens. This was followed by Type VI in 11 (15.71%), Type I in 10 (14.28%), Type II in 5 (7.14%), and Type IV in 4 (5.71%) speciments. Type V suprascapular notch was not observed (0, 0%) in the present study. The distribution of suprascapular notch types was found to be statistically significant (p<0.05). Conclusion The current study reveals that Type III suprascapular notch is the predominant morphological pattern. Variations involving narrowing of the notch or transverse scapular ligament ossification may likely lead to suprascapular nerve entrapment. Awareness of these anatomical variations is clinically important for orthopaedic surgeons, radiologists, and clinicians involved in the evaluation and management of shoulder pathologies.