upper limb nerve injuries Flashcards
what is the difference between a spinal cord injury and a spinal nerve injury?
spinal cord injury = all nerves below point of injury are affected (neural level etc)
spinal nerve injury = only the individual nerve is affected
what are the different types of nerve injuries?
4 S’s:
* stretched
* squashed
* severed
* stressed
- what is the mechanism of injury of the musculocutaneous nerve?
- what is the motor supply of the musculocutaneous nerve? what is the effect of the injury?
- what is the effect on sensory supply in a musculocutaneous nerve injury?
- trauma
- anterior arm muscles weakened - BBC
- loss of the lateral cutaneous nerve causes loss of sensation on lateral aspect of forearm
- what is the mechanism of injury of the axillary nerve?
- what is the motor supply of the axillary nerve? what is the effect of the injury?
- what is the effect on sensory supply in a axillary nerve injury?
- anterior shoulder dislocation, surgical neck of humerus fracture, compression in quadrangular space
- weakness in deltoid so weakness in those actions, weakness in teres minor + loss of abduction from 15-90 degrees
- loss of sensation in regimental badge region
- what is the mw
- what is the motor supply of the long thoracic nerve? what is the effect of the injury?
- blunt trauma, latrogenic-masectomy with axillary clearance
- loss of serratus anterior function - protraction
what nerve damage is associated with mid-shaft humeral fracture?
nerves to tricep and sensory nerves to arm and forearm ar given off before whilst the radial nerve is in the spinal groove
therefore patients experience:
wrist drop - can’t extend at wrist
paraesthesia in dorsum of hand and lateral 3.5 digits
- what is the mechanism of high median nerve injury?
- what is the motor supply of the high median nerve? what is the effect of the injury?
- what is the effect on sensory supply in a high median nerve injury?
- supracondylar fracture
2.
how do you test for high median nerve injury?
ask patient to make a fist
show hand of benediction
unable to flex 2nd and 3rd digit
thumb adducted and interphalangeal joint extended
what are the effects of high median nerve injury?
- index and middle finger is unable to flex - flexors of fingers and radial half of FDP lose nervous supply
- ring and little finger are able to flex - ulnar nerve still supplies ulnar half of FDP intact
thumb: - adducted as adductor pollicis longus functional as supplied by ulnar nerve
- extended interphalangeal joint FPL + FPB supplied by median nerve so lost
what are the 2 causes of median nerve injury at wrist?
compression - carpal tunnel syndrome
laceration
what are the effects of carpal tunnel syndrome?
nerve supply to forearm muscles preserved
LOAF is lost
sensory loss to radial 3 1/2 digits
what are the effects of wrist lacerations?
nerve supply to forearm muscles preserved motor/sensory loss depends on depth/location of injury
- what is the mechanism of distal ulnar nerve injury?
- what is the motor supply of the distal ulnar nerve? what is the effect of the injury?
- laceration or compression in guyon’s canal
- intrinsic hand muscles lost (except LOAF), forearm muscles intact
why is distal ulnar claw seen at rest in a distal ulnar nerve injury?
4th and 5th digits:
1. hyperextension at MCPJ
2. flexion at PIPJ
3. flexion at DIPJ
how are the lumbricals involved associated with distal ulnar nerve injury?
loss of supply to medial 2 lumbricals so cant carry out normal function:
* cant flex at MCPJ
* cant extend at DIPJ and PIPJ
forearm flexors and extensors function so we see opposite of normal lumbrical action as forces are unbalanced
