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.