During dissection an anomalous muscle was found on the medial aspect in the distal half of one left upper extremity. This muscle arose from the humerus between the m. coracobrachialis and the m. brachialis, passed obliquely across the front of the brachial artery and median nerve and blended with the common origin of the forearm flexor muscles. It does not appear to be an additional head of the biceps brachii or the brachialis muscles. The existence of this anomalous muscle should be kept in mind in a patient presenting with a high median nerve palsy together with symptoms of brachial artery compression.
The arterial and muscular variations of the upper limbs are common but important with regard to surgical approaches. Even though anomalies of the coracobrachialis muscle are rare, anatomical variations of the biceps brachii, existence of the accessory muscles in the forearm and persistent median artery are known and well documented. During routine dissection, we observed some important anatomical variations in a 50-year-old male cadaver. The variations were unilateral. The anomalies were: third head for biceps brachii muscle, an accessory belly for coracobrachialis muscle crossing the median nerve and brachial vessels and continuing with the medial head of triceps brachii muscle to be inserted to the olecranon process (coracoulnaris), a persistent median artery and an additional muscle in the anterior compartment of forearm. Although there are individual reports about these variations, the combination of these variations in one cadaver has not previously been described in the literature. Awareness of these variations is necessary to avoid complications during radiodiagnostic procedures or surgeries in the upper limb.