During dissection an anomalous muscle was found on the medial aspect i
n the distal half of one left upper extremity. This muscle arose from
the humerus between the m. coracobrachialis and the m. brachialis, pas
sed obliquely across the front of the brachial artery and median nerve
and blended with the common origin of the forearm flexor muscles. It
does not appear to be an additional head of the biceps brachii or the
brachialis muscles. The existance of this anomalous muscle should be k
ept in mind in a patient presenting with a high median nerve palsy tog
ether with symptoms of brachial artery compression.