Editing Upper limb (section)

=== '''Ulnar nerve''' ===

** Origin
*** Direct continuation of the       medial cord (C8, T1) but 95% pick up C7 fibres from the lateral cord
** Course
*** Runs down arm with brachial       artery
*** Penetrates medial       intermuscular septum in mid-arm and passes posteriorly, reaching the       groove behind the medial epicondyle of the humerus.
*** In the forearm, lies close       to distal ulnar artery.
*** Enters palm of hand via       Guyon's canal
*** Main branch gives off       digital nerves, and also supplies superficial palmaris brevis.
*** Branches
**** Dorsal branch - arises in        the distal forearm 5cm from the wrist flexion crease and passes between        FCU and the distal ulna to reach the ulnar side of the dorsum of the        hand
** Supplies
*** Flexor muscles of the ulnar       side of the forearm - FCP and medial two parts of FDP
*** Most of the intrinsic       muscles of the hand - HILA
**** Hypothenar eminence
**** Interossei
**** Lumbricals (medial two)
**** Adductor pollicis
*** Cutaneous to the skin of       the ulnar 1.5 digits, and hypothenar eminence
** Injuries:
*** Most commonly injured       behind the elbow or at the wrist
*** Low lesion (at the wrist       e.g. lacerations)
**** Claw hand on attempted        finger extension - hyperextension of the MCPJ of the ring and little        fingers, and flexion of IPJ (unopposed action of the extensors and FDP)
****
**** Sensory loss 1.5 fingers
*** High lesion (elbow or above       e.g. fracture, dislocation, damage behind medial epicondyle)
**** Paradoxical straighter        fingers because loss of the ulnar half of FDP - can't flex the distal        IPJs of the ring and little fingers
**** Sensory loss 1.5 fingers
*** Deformity - wasting of       hypothenar eminence and intrinsic muscles of hand