Multiple existence of supernumerary heads of the biceps brachii, coracobrachialis longus, dual accessory brachialis, and a Y-shaped axillary arch muscles in the unilateral arm of a Thai cadaver.

Abstract

While single or dual variations of the brachial muscle have been documented, multiple muscular variations in the anterior compartment of the arm are relatively uncommon. Therefore, we aim to report the multiple muscular variation in the anterior compartment of the arm. During routine dissection, we observe the muscular variations including supernumerary heads of the biceps brachii, coracobrachialis longus, double accessory brachialis, and axillary arch muscles in the right arm of a 92-year-old male Thai cadaver. These variant muscles were supplied by branches from the musculocutaneous nerve and brachial artery. The unusual course of these muscles was associated with the neurovascular bundle, which may increase the risk of entrapment of neuropathy. Furthermore, it is essential to understand these anatomical variations to improve surgical procedures in the brachial field.