Bilateral rare variation in origin of biceps brachii short head tendon with clinical implications

While reports of supernumerary heads of the biceps brachii muscle are common, variants of the short head of the biceps brachii tendon are rare, and bilateral presentations have not been previously reported. This case presents novel variants of attachments along a broad aponeurosis present bilaterally that was identified during routine student cadaveric dissection. On the right shoulder, the aponeurosis extended from the coracoid process, where it formed a conjoint tendon with the coracobrachialis, to the lesser tubercle of the humerus where it fused with the tendon of the pectoralis major muscle. On the left shoulder, the aponeurosis extended from the coracoid process to the greater tubercle of the humerus, with an arterial branch passing through the tendon. The presence of a broad aponeurosis of the biceps brachii short head across the shoulder capsule has implications for mobility and surgical approach to the shoulder.