ABSTRACT
Variations in branching pattern of the brachial plexus are common and have been reported
by several investigators. Of the four main nerves traversing the arm, namely median,
ulnar, radial and musculocutaneous, the ulnar and median nerve do not give any branches
to muscles of the arm. Ulnar nerve after taking origin from medial cord of brachial
plexus runs distally through axilla on medial side of axillary artery till middle
of arm, where it pierces the medial intermuscular septum and enters the posterior
compartment of arm. Ulnar nerve enters forearm between two heads of flexor carpi ulnaris
from where it continues further. It supplies flexor carpi ulnaris , flexor digitorum
profundus and several intrinsic muscles of hand . We recently observed dual supply
of biceps muscle from ulnar and median nerves in arm. Musculocutaneous nerve was absent.
Although communications between nerves in arm is rare, the communication between median
nerve and musculocutaneous nerve were described from the 19th century which could
explain innervation of biceps from median nerve. But no accurate description of ulnar
nerve supplying biceps could be found in literature. Knowledge of anatomical variation
of these nerves at level of upper arm is essential in light of the frequency with
which surgery is performed to transfer nerve fascicles from ulnar nerve to biceps
in case of brachial plexus injuries. We also observed third head of biceps, our aim
is to describe the exact topography of this variation and to discuss its morphological.
KEY WORDS
Ulnar nerve - biceps - median nerve
