Rare case of median nerve and brachial artery entrapment by an abnormal musculo-fascial tunnel in the arm: possible cause of neurovascular compression syndrome

Entrapment neuropathies of the peripheral nervous system are frequently encountered due to anatomical variations. Median nerve is the most vulnerable nerve to undergo entrapment neuropathies. The clinical complications are mostly manifested by median nerve impingement in forearm and wrist areas. Median nerve entrapment could also occur at the arm, due to the presence of ligament of Struthers. Here we report a rare case of proximal entrapment of median nerve and brachial artery in the arm by an abnormally formed musculo-fascial tunnel. The tunnel was formed by the muscle fibers of brachialis and medial intermuscular septum in the lower part of arm. Due to this, the median nerve coursed deep, below the tunnel and continued distally into the forearm, underneath the pronator teres muscle and hence did not appear as a content of cubital fossa. The present entrapment of neurovascular structures in the tunnel might lead to pronator syndromes or other neurovascular compression syndromes.