Variations in the Shape and Dimension of the Suprascapular Notch in Dried Human Scapula-An Osteological Study with its Clinical Implications

Introduction: The suprascapular notch is a depression on the superior border of scapula which gives passage to the suprascapular nerve to enter the supraspinatus fossa. During its course there is a chance of entrapment of the nerve while in the notch due to its variant shapes and dimensions which leads to suprascapular nerve entrapment syndrome Aim: The purpose of the study was to determine the variations of the shape and dimensions of suprascapular notch of scapula because these parameters may be the causative factors in nerve compression. Materials and Methods: A total 110 dried human scapula of both sides were included in the study. First they were grossly examined for variations in shape of the notches. Then vertical and transverse dimensions of the notches were measured with the help of digital vernier calliper. Results: As per classification by shape we found 43 ‘J’ shaped (39.09%), 35 ‘U’ shaped (31.81%), 10 ‘V’ shaped (9.09%), indentation in eight cases (7.27%), absent in five (4.54%), partial ossification of STSL in four (3.63%) and complete ossification in five (4.54%) scapulae. The results were also analysed according to Natsis classification after excluding the Scapulae with indentation and partial ossification of ligament. Five (5.1%) scapulae Type I, sixty six scapulae (67.34%) had Type II, 14 scapulae (14.28%) had Type III, five (5.1%) had Type IV and none (0%) had Type V. We also found eight scapulae (8.16%) with transverse diameter equal to the vertical diameter (Td=Vl). Conclusion: The present study showed various types of suprascapular notches. Out of these Iqbal type ‘U’ and Natsis type II were most predominant. In both the cases chance of suprascapular nerve compression is less as more space is available to the nerve. The present study also showed five cases of completely ossified STSL where chances of impingement are higher. Since, these anatomical variations are not uncommon in population so there is a need for clinicians to have precise anatomical knowledge of SSN before making proper diagnosis and planning for surgical interventions of suprascapular nerve entrapment syndrome. We hope our study will be helpful in providing anatomical knowledge to the clinicians. A na to m y S ec tio n