A Study on Morphometry and Morphological Variation of Suprascapular Notch in Dried Human Scapula

Introduction: The Suprascapular Notch (SSN) is located at the superior border of the scapula, just medial to the base of the coracoid process. The knowledge of variations in shapes and dimensions can be helpful to clinicians to correlate the suprascapular nerve entrapment with a specific type of notch. Aim: This study was carried out to observe morphological variation in shapes of SSN and morphometric analysis of SSN. Materials and Methods: A total of 120 adult scapulae of unknown age and sex will be obtained from Department of Anatomy, GMERS Medical College, Gandhinagar and Sola, Gujarat, India. The shapes of SSN were observed and dimensions were taken by digital Vernier caliper. Results: The most common type of SSN observed was Type 2, a notch that was longest in its transverse diameter. The least common type was Type 4. Type 5 SSN was absent. The most common shape was ‘J’ and least common was ‘V’.Partial and complete ossification was also noted. Conclusion: Knowledge of anatomical variations of suprascapular notch is better for understanding location and source of entrapment syndrome. Since, the present study is performed with a limited number of dry scapulae, so there is need of further clinical, radiological and cadaveric studies. A na to m y S ec tio n A Study on Morphometry and Morphological Variation of Suprascapular Notch in Dried Human Scapula SudArShAn GuptA, ZArnA pAtel, deepAk howAle InTROduCTIOn The scapula in humans is located between second to seventh ribs in the post lateral part of the chest. It is a flat bone which is triangular in shape. At the superior border of scapula, a notch is present medially to coracoid process base. This notch is called the SSN. Suprascapular nerve passes through SSN which is motor nerve to supraspinatus and infraspinatus muscles,and sensory to rotator cuff muscles, ligamentous structures of shoulder andacromio-clavicular joint [1]. The suprascapular nerve passes through the suprascapular foramen which is created by the attachment of superior transverse scapular ligament to the notch [2]. Kopell and Thompson were the first to describe suprascapular nerve entrapment syndrome at SSN [3]. Over the years, many studies have investigated anatomical variations in the SSN and found out that ossified suprascapular ligament is one of the possible cause for development of suprascapular neuropathy [4]. It is characterized by shoulder pain, weakness in arm, difficulty in external rotation and abduction, and atrophy of supraspinatus and infraspinatus muscles.This syndrome is commonly seen in those who are involved in overhead heavy keywords: Ossified suprascapular ligament, Rotator cuff, Suprascapular nerve entrapment syndrome work, athletes such as baseball players, volleyball players, weight lifters etc., [4]. The SSN was classified into six types by Rengachary et al., [5-7], based on the shape of notch. This study has been planned with the following objectives: 1) To find out the prevalence of the various shapes of SSN. 2) Morphometric analysis of different shape of SSN and to find out the any difference in measurements of different shape and on right and left side scapulae. MATeRIAlS And MeThOdS This is an observational analytical type of study to determine the morphological variations and morphometric analysis of SSN in dried human scapulae conducted at Department of Anatomy of GMERS Medical College, Gandhinagar, Gujarat, India during September 2016 to December 2016 (4 Months). Using Epi Info 7 by CDC Atlanta [8], and considering a prevalence rate of variation in shape of SSN as 26.9% from previous studies [9], confidence level as 95%, acceptable margin of error as 8% and design effect of 1, the provisional sample size was calculated to be 120. These 120 human dried scapula of unknown age and sex were obtained