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2023, Volume 31, Issue 1

Case Report

Accessory Subscapularis muscle compressing posterior division of upper trunk: A rare presentation

Vinay Sharma, C S Ramesh Babu

Pages: 56-60


Presence of additional or accessory muscles near the axilla can lead to compression of vital structures of the axilla. Opposite conventional thoughts, it seems that the subscapularis muscle (SM) is the most variable muscle of the rotator cuff group. Accessory Subscapularis muscle is one of the rare variants of the Subscapularis muscle. Presence of this variant (ASsm) can cause abnormal clinical presentation. During routine dissection of the axilla in a female cadaver in the Department of Anatomy, Muzaffarnagar Medical College, we found an additional slip or accessory subscapularis muscle, arising from the anterolateral part of the Subscapularis and running upward and medially, finally attached to the coracoid process (palpated tip). During its course, it passed through the Brachial plexus and caused compression of the posterior division of the Upper trunk. This type of accessory slip or accessory subscapular muscle can cause compression neuropathy, or this accessory slip can be used during the repair of a ruptured Subscapularis or any other adjacent muscle.

Keywords: Accessory Subscapularis Muscle, Rotator Cuff Variants, Brachial Plexus Compression

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