ULNAR NERVE

INTRODUCTION:
  • Also known as musician nerve
  • Arises from C7,8 & T1 roots
  • Arises from the medial cord of brachial plexus.
  • Enters the palm by passing superficial to flexor retinaculum.
  • Lies between the pisiform & ulnar vessels
  • Most common nerve used for monitoring during anaesthesia is ulnar nerve.
  • Forms Martin-Gruber connections with Median nerve.
  • Cervical rib if present it causes pressure on ulnar nerve.
COURSE OF ULNAR NERVE:
  • Ulnar nerve passes through cubital tunnel behind the elbow.
  • Ulnar nerve enters the palm passing superficial to flexor retinaculum (transverse carpal ligament) lying just lateral to pisiform. Here ulnar nerve et artery lie under cover of a fascial band called as volar carpal ligament, the space under it is known as ULNAR TUNNEL.
  • Deep terminal branch of ulnar nerve passes through Guyon's canal (pisohammate tunnel) under cover of pisso ham mate ligament.
  • Structure passing through tarsal tunnel is posterior tibial nerve.
DIVISION:
  • It divides into superficial & deep branches.
  • Superficial branch: Palmaris brevis & medial 1 1/2 digits with their nail beds
  • Deep branch: accompanies deep ulnar artery & supplies 3 muscles of hypothenar eminence(abductor digitii minimi, flexor digitii minimi and opponens digitii minimi), medial two lumbricals(3rd & 4th), eight interossei, adductor pollicis & wrist joint and occasionally deep head of the flexor pollicis brevis. (All intrinsic muscles of hand are supplied by deep branch)
SUPPLIES:
  • Sensory Supply:
Hand: Anterior ->medial 1/3of palm;             Posterior →medial 1/2 of palm.
Digits: Anterior → medial 1 1/2digits;           Posterior →medial 2 1/2 digits.
  • -Also supplies skin over Hypothenar eminence
Motor Supply:
  • Forearm: Flexor carpi ulnaris & Medial 1/2 of flexor digitorum profundus.
Hand:
  1. Hypothenar muscles: Palmaris brevis [by superficial branch], other 3 muscles [by deep branch]
  2. Thenar muscle: Adductor pollicis only(most commonly observed during preoperative period for neuromuscular blockade. If adductor pollicis is showing no activity it means 
  3. laryngeal muscles have already been blocked and intubation can be performed.At the reversal, if there is activity in adductor pollicis it means that diaphragmatic activity has already returned and the patient will be able to maintain tidal volume even after extubation).
  4. Four palmar interossei & four dorsal interossei(deep branch).
  5. Medial two lumbricals (3rd& 4th)
NOTE:
  • Tip of little finger is the autonomous zone for ulnar nerve
  • All the Intrinsic muscles of hand are supplied Ulnar Nerve (C7, C8, T1) except 1st & 2nd lumbricals and muscles of thenar eminence.
  • The 1st and 2nd lumbricals, muscles of thenar eminence are supplied by Median N (C8, T1).

Exam Question
  • Ulnar nerve is Also known as musician nerve
  • Ulnar nerve Arises from C7,8 & T1 roots
  • Most common nerve used for monitoring during anaesthesia is ulnar nerve.
  • Forms Martin-Gruber connections with Median nerve.
  • Cervical rib if present it causes pressure on ulnar nerve.
  • Deep branch: accompanies deep ulnar artery & supplies 3 muscles of hypothenar eminence(abductor digitii minimi, flexor digitii minimi and opponens digitii minimi), medial two lumbricals(3rd & 4th), eight interossei, adductor pollicis & wrist joint and occasionally deep head of the flexor pollicis brevis. 
  • Also supplies skin over Hypothenar eminence
  • Hypothenar muscles is supplied by deep branch of ulnar nerve
  • The four dorsal interossei is supplied by deep branch of ulnar nerve

Don't Forget to Solve all the previous Year Question asked on ULNAR NERVE