Peripheral nerve injuries

Neurapraxia

  • Temporary loss of function caused by minor trauma or pressure
  • Recovery occurs within minutes

Axonotmesis

  • Loss of function due to severe ischaemia
  • Recovery occurs within weeks

Neurotmesis

  • Loss of function due to division of nerve
  • No recovery occurs unless nerve is repaired

Radial nerve

  • Often injured in radial groove of humerus
  • Motor paralysis results in typical 'wrist drop' due to loss of:
    • Extension of elbow, wrist, knuckles and all joints of thumb
    • Supinator and brachioradialis
  • Sensory loss involves dorsum of 1st, 2nd and 3rd metacarpals
  • May be as small as the anatomical snuffbox

Median nerve

  • Often injured by penetrating wounds of the forearm
  • Motor paralysis due to loss of:
    • The pronators
    • Radial flexor of the wrist
    • Flexors of all of the proximal interphalangeal joints
    • Flexors of the terminal joint of the thumb, index and middle finger
    • Abductor and opponens pollicis
  • Sensory loss over thumb, index, middle and half of ring fingers

Ulnar nerve

  • Often injured with fractures of the medial epicondyle of the elbow
  • Motor paralysis results in 'claw hand' and hypothenar wasting due to loss of:
    • Ulnar flexor of the wrist
    • Flexors of the terminal phalanx of the ring and little finger
    • Muscles of the hypothenar eminence
    • Adductor pollicis
    • Palmar brevis
  • All the interossei and the medial two lumbricals
  • Sensory loss over little and half of ring finger

ulnar nerve palsy

Picture provided by Loh Yin, International Medical University, Jolam Rasah. Malaysia

Brachial plexus injuries

  • Usually occur in two situations
    • Difficult vaginal deliveries associated with the use of forceps
    • Traction during a fall or road traffic accident

Erb's palsy

  • Due to damage to the upper nerve roots
  • Usually involves C5, C6, C7
  • Abductors and external rotators of the shoulder are affected
  • Loss of finger extension
  • Sensation is intact

Klumpke's palsy

  • Due to damage to the lower nerve roots
  • Usually involves C8, T1
  • All finger muscles are paralysed
  • Loss of sensation
  • Often associated with unilateral Horner's syndrome

Bibliography

Leffert R D.  Nerve lesions about the shoulder.  Orthop Clin North Am 2000;  31:  331-345.

Terzis J K,  Vekris M D,  Soucacos P N.  Brachial plexus root avulsions.  World J Surg 2001;  25:  1049-1061

 

 
 

Last updated: 05 January 2008

Copyright © 1997- 2008 Surgical-tutor.org.uk