W3 nerve injuries Flashcards
• Considerations
o Loss of nerve to muscle results in atrophy
o Weakness of a movement comes from a movement done by multiple muscles with multiple innervations
o Loss of movement comes when all the muscles involved are innervated by the same nerve
o Loss of muscle function results in opposite function/motion being dominant
o Injury to nerve is associated with sensory loss as well
• Injury to axillary nerve
o Anterior dislocation of humerus and fracture of surgical neck of humerus
o Weakness in abduction of the arm
o Sensory loss on lateral shoulder and upper arm
• Injury to radial nerve
o Midshaft fractures of the humerus
o Loss of wrist and digit extension
o Weakness in supination
o Sensory loss on posterior arm and forearm and dorsum of the hand
• Common injuries to median nerve
o Fractures of elbow and distal humerus
o Carpal tunnel syndrome
• Supraepicondylar fracture of the humerus
o Median nerve damage
o Weakened wrist flexion
o Hand deviates to the ulnar side when wrist is flexed
o Loss of index and middle finger flexion at MP, DIP, and PIP joints
o Weakness of thumb abduction, loss of thumb opposition and loss of thumb flexion
o Loss of pronation
o Sensory loss on palmar and dorsal aspects of index, middle and half of ring fingers and palmar aspect of thumb
• Carpal tunnel syndrome, fracture, or laceration
o Median nerve damage
o Weakness of thumb abduction and flexion, loss of thumb opposition (atrophy of thenar pad)
o Sensory loss on palmar and dorsal aspects of index, middle and half of ring fingers and palmar aspect of thumb
• Deep branch of median nerve (anterior interosseous nerve)
o Sparing of main median nerve due to compression by muscles or from forearm fractures
o Weakness of thumb flexion
o Loss of flexion of the DIP joint of the index and middle fingers
o Weakness of pronation
o Can’t make a normal “OK” sign with fingers
o No sensory loss
• Common injuries to the ulnar nerve
o Fractures of the medial epicondyle or
o compression of the nerve against bone as with “tennis elbow” or
o fractures or lacerations to the ventral medial side of the wrist
• entrapment at the elbow or medial epicondyle fractures
o ulnar nerve
o loss of abduction and adduction of fingers
o loss of thumb adduction
o loss of flexion at the 4th and 5th digits at DIP joint
o hand deviates to radial side when flexed
o can’t make a fist
o sensory loss on medial side of hand and aspects of 4th and 5th digits
• wrist fracture or laceration
o ulnar nerve
o loss of abduction and adduction of the fingers
o loss of thumb adduction
o sensory loss on medial side of hand and aspects on the 4th and 5th digits
• musculocutaneous nerve lesion
o weakness of forearm flexion
o weakness of hand supination
o weakness of arm flexion
o sensory loss on lateral forearm
• upper brachial plexus injury
o Erb’s palsy
o Separation of head from shoulder often encountered in birth or fall on the shoulder
o C5 and C6 roots
o Musculocutaneous, axillary, and suprascapular nerves
o Deformity: arm hangs by side and is adducted and medially rotated, forearm is extended and hand protonated
o Disability: abduction and lateral rotation of arm, flexion and supination of hand, sensations lost over lower part of shoulder
• Lower brachial plexus injury
o Klumpke’s palsy
o Undue abduction of arm as in clutching something with hands after a fall from a height, or a birth injury
o C8 and T1 roots
o Ulnar and maybe median nerve
o Deformity: ulnar claw hand due to unopposed flexors and extensors (hyperextension of the MP joints and flexion at the IP joint)
o Disability: intrinsic muscles of the hand, ulnar flexors of the wrist and fingers, sensations lost over ulnar borders of the forearm and hand
