Communication between the musculocutaneous and median nerves in the arm: an anatomical study and clinical implications

OBJECTIVE: To determine the frequency and features of communication between the musculocutaneous nerve (MCN) and median nerve (MN) in a sample of the Colombian population, and assess its clinical implication. METHODS: The arms of 53 cadaver specimens that had been subjected to necropsy at the National Institute of Forensic Medicine, in Bucaramanga, Colombia, were studied. The structures of the anterior compartment of the arm were dissected and characterized regarding the presence of communication between the MCN and MN. RESULTS: A communicating branch was found in 21/106 upper limbs (19.8%), occurring bilaterally in 10 (47.6%) and unilaterally in 11 (52.4%), without significant difference regarding the side of occurrence (p = 0.30). In 17% of the cases, there was MCN-MN communication in which the communicating branch was seen leaving the MCN after piercing the coracobrachialis muscle (Type I). In 2.8%, the connection was from the MN to the MCN (Type II). The length of the communicating branch was 57.8 ± 33.4 mm. The distances from the proximal and distal points of this branch to the coracoid process were 138 ± 39.4 mm and 188 ± 48.3 mm, respectively. The communicating branch was located mostly in the middle third of the arm. CONCLUSIONS: The frequency of MCN-MN communication observed in the present study is in the middle of the range of what was reported in previous studies. MCN-MN connections need to be taken into account in diagnosing and managing peripheral nerve lesions of the upper limbs.