The suprascapular notch: its morphology and distance from the glenoid cavity in a Kenyan population.

Abstract

The morphology of the suprascapular notch has been associated with suprascapular entrapment neuropathy, as well as injury to the suprascapular nerve in arthroscopic shoulder procedures. This study aimed to describe the morphology and morphometry of the suprascapular notch. The suprascapular notch in 138 scapulae was classified into six types based on the description by Rengachary. The suprascapular notch was present in 135 (97.8%) scapulae. Type III notch, a symmetrical U shaped notch with nearly parallel lateral margins, was the most prevalent type, appearing in 40 (29%) scapulae. The mean distance from the notch to the supraglenoid tubercle was 28.7 ± 3.8 mm. This varied with the type of notch, being longest in type IV (30.1 ± 1.8 mm) and shortest in type III (27.3 ± 2.3 mm). The mean distance between the posterior rim of the glenoid cavity and the medial wall of the spinoglenoid notch at the base of the scapular spine was found to be 15.8 ± 2.2 mm. Type III notch was the most prevalent, as found in other populations. In a significant number of cases the defined safe zone may not be adequate to eliminate the risk of nerve injury during arthroscopic shoulder procedures, even more so with type I and II notches.