Asymmetric Bilateral Variations in the Musculocutaneous and Median Nerves with High Branching of Brachial Artery

Abstract

Summary: Brachial Plexus is formed by the union of the anterior rami of cervical 5, 6, 7, 8 and thoracic 1 nerves. These nerves unite and divide to form the key nerves innervating the upper limb. Variations in the course of these nerves are clinically important to anesthetists, neurologists and orthopedicians. we report bilateral variations in the arterial and neural structures in the upper limb of a 65 year old cadaver. The muscles of the arm on one side were innervated by the median nerve with absence of musculocutaneous. while on the other side the musculocutaneous nerve contributed to the formation of the median nerve. There was a presence of high bifurcation of brachial artery on both sides. Knowledge of such variations in the innervations of muscles and the arterial supply of the limbs are important to remember before performing any reconstructive procedures or interventions on the limb.

Absence of Musculocutaneous Nerve Associated with Variations of Distribution Patterns of the Median Nerve

“…Therefore, the musculocutaneous nerve may be absent or variation from theoretical point of view. Related variation or absence of the musculocutaneous nerve has been reported in the literature (Fregnani et al, 2008;Pacholczak et al, 2011;Tomar & Wadhwa, 2012).…”

Absence of the Musculocutaneous Nerve and Associated Compensation by the Median Nerve

“…Furthermore, this finding was associated with high branching of the brachial artery. 18 Finally, there are reports about further variations of the median nerve. These include variations in its subbrachialis course, its entrapment in the brachialis muscle along with the brachial artery, and its formation with three roots.…”