Abnormal musculotendinous slip from Biceps Brachii to Pronator Teres: A Case Report

Variations of upper limb muscles are quite commonly seen during dissection. Biceps Brachii take an edge on this, as it commonly has two or more than two sites of origin and insertion, where mode of insertion being both aponeurotic as well as tendinous. In present study, apart from common modes of insertion, an additional musculotendinous slip was seen running from the medial side of the muscle belly of Biceps Brachii to Pronator Teres and Flexor Carpi Radialis deep to the aponeurosis. The functional aspect of such insertion is also questionable as Biceps brachii being a supinator is gaining attachment to a Pronator Muscle. Presence of such abnormal musculotendinous tissue can pose a difficult situation during surgical procedures in and around cubital fossa and can also be a cause of nerve entrapment syndromes. Additional muscular slip can lead to compression of neurovascular structure around that area.