[Contribution to subscapularis nerve supply. 18 dissections]

Dividing the subscapularis muscle along its fibers axis allows approaching the glenohumeral joint. The more medial its division, the more possible injury of its nerve supply.

The aim of our study was to assess the subscapularis nerve supply through cartography of the entry points of subscapularis nerves from simple landmarks, reproducible by triangulation.

On 18 formalin-preserved shoulders, after dissection of the subscapularis nerves, distances were measured between entry points of subscapularis nerves and the following landmarks: center of the minor tubercle (tm), upper and lower poles of the glenoid cavity (cgs and cgi), apex of the coracoid process (pc).

There were in average 3.33 subscapularis nerves (2-4). These different nerves split most often before entering subscapularis muscle; there were in average 5.05 entry points (3-6). Distances between entry points and clinical landmarks were as follows: cgs, 3.9-6.45 cm; cgi, 3.7-5.54 cm; tm, 5.9-7.15 cm; pc, 4.9-7.66 cm. Reporting these measurements onto a frame allowed to show that all these points were located in average medially to the scapular notch and at more than 3 cm from the anterior border of the glenoid cavity.

If the transverse division does not extend farther than 3 cm from the anterior border of the glenoid cavity and from the medial border of the root of the coracoid process, there should not be any injury of the subscapularis nerves.