4. After the ulnar
nerve passes
behind the medial
epicondyle, it
enters the forearm
between the two
heads of the flexor
carpi ulnaris
muscle.
5.
6. The nerve gives branches to
the flexor carpi ulnaris and
the medial half of the flexor
digitorum profundus.
The ulnar nerve then travels
along side the ulna bone of
the forearm into the wrist.
As the nerve descends into
the forearm, it stays medially
above the flexor digitorum
profundus and under the
flexor carpi ulnaris, giving
branches to these muscles.
7. In the lower part
of the forearm the
ulnar nerve lies
lateral to the
flexor carpi
ulnaris muscle and
medial to the
ulnar artery.
8. At the wrist, the ulnar nerve lies just
lateral to the pisiform bone.
The superficial branch of the ulnar
nerve supplies and passes under the
palmaris brevis muscle and divides into
palmar digital nerves.
The deep branch of the ulnar nerve
innervates the three hypothenar
muscles, the medial two lumbricals, the
seven interossei, the adductor pollicis
and the deep head of the flexor pollicis
brevis.
It supplies all intrinsic hand muscles
which lie medial to the flexor pollicis
longus except the lateral two lumbricals
(median n.)
10. The ulnar nerve provides
palmar and dorsal sensory
innervation to the little finger
and half of the ring finger.
Pinching of the ulnar nerve
often causes paresthesia in the
fourth & Fifth digit.
Entrapment or injury of the
ulnar nerve below the elbow
may result in a claw hand
deformity due to the
unopposed preserved function
of the flexor digitorum
profundus.
