INNERVATION OF THE MEDIAN NERVE MOTOR BRANCHES IN THE FOREARM AND ITS CLINICAL SIGNIFICANCE

OBJECTIVE: To analyse the anatomical variations of the median nerve motor branches in the elbow region. METHODS: Twenty upper limbs of 10 adult male cadavers were prepared by intra-arterial injection of a solution of 10% glycerol and formaldehyde. All cadavers belonged to the institution anatomy laboratory. RESULTS: We found a great variability within the distribution of median nerve branches leading to forearm muscles. Only three limbs (14%) presented the normal standard of innervation described in anatomy treatises. The pronator teres muscle (PTM), flexor carpi radialis (FCR), palmaris longus (PL), and the flexor digitorum superficialis (FDS) received exclusive innervation from the median nerve in all forearms. The anterior interosseous nerve (AIN) also originated from the median nerve in all dissected limbs. CONCLUSION: A thorough understanding of the anatomy of the median nerve branches is important for performing surgeries such as: approach to the proximal third of the forearm, alleviation of pronator teres and anterior interosseous nerve compression syndromes, and distal nerve transfers. It also enables a better understanding the recovery of muscle function after a nerve injury. Level of Evidence IV, Case series.