peripheral nerve injuries Flashcards
what nerve roots are damaged in erbs palsy (upper brachial plexus injury)?
C5 and C6
what nerve roots are damaged in klumpke’s paralysis (lower brachial pleus injury)?
- C8 & T1
what roots does the long thoracic nerve come off?
C5, C6, C7
what can cause erbs palsy?
widening of the angle between the neck and shoulder
what is the deformity seen with erbs palsy & why?
- waiters tip
- C5 & C6 damaged - lateral cord damaged - musculocutaneous and median nerve damaged - unable to flex arm and forarm and wrist - so arm 7 wrsit stays in an extended position
what can cause klumpke’s paralysis?
an increased angle between the trunk and arm
what deformity is seen with klumpke’s paralysis?
a claw hand
what structures does the median nerve provide motor innervation/ function to?
- flexor muscles in forearm EXCEPT FCU and 1/2 of FDP
- first & second lumbricals
- muscles of thenar eminence (thumb) - OAF
what would a disability of the median nerve look like - what symptoms might the patient have?
- wasting of thenar eminence
- ape like hand
- loss of opponens muscle
what is a good test to test for median nerve injury?
- ask the patient to oppose their thumb - they should be unable to with a median nerve injury
what are examples of situations that could cause a median nerve injury?
- laceration (cut) at elbow
- fractures at elbow
- laceration at the wrist
- carpel tunnel syndrome (compression of the median nerve)
what kind of symptoms can be seen with carpal tunnel syndrome?
- pins and needles
- burning pain
- possible wasting of thenar eminence over time
- most patients with this syndrome have normal power and may have symptoms but no signs
what muscles does the ulnar nerve provide motor innervation to?
- flexor carpi ulnaris and 1/2 of FDP
- hypothenar eminence
- interossei muscles
- adductor pollicis
what are examples of ulnar nerve motor disability symptoms?
- partial claw hand
- wasting of the hypothenar eminence
- wasting of the interossei
- loss of DAB & PAD
- loss of adduction of thumb
what is a partial claw hand?
partial clawing of the litte and ring finger
how can the adductor pollicus muscle be tested?
- froments test
- ask the patient to pinch a piece of paper between the thumb and index finger
- if an ulnar nerve injury is present, the patient will flex their thumb - showing weakness of adductor pollicis
what is the ulnar nerve paradox?
- this refers to the difference in severity of ulnar nerve injury between a lesion at the elbow compared to the wrist
- lesion at or above the elbow - causes loss of flexor digitorum profundus - therefore loss of flexion at the IP joints
- a lesion at the wrist would cause weakness of the hand muscles
what are examples of situations that could cause axillary nerve lesions?
- dislocated shoulder
- fracture of the surgical neck of the humerus
- deltoid injections - paralysis of deltoid or loss of sensation over the regimental patch
what is the regimental patch?
a patch of skin at the top of the upper arm
what are examples of situations and conditions that could cause radial nerve injuries?
- fracture of the midshaft of the humerus
- crutch palsy (compression of the nerve caused by crutches)
- saturday night palsy - prolonged direct pressure on the axillary region
what are examples of disabilities that are seen with radial nerve injuries?
- wrist drop - due to the loss of the wrist extensors
- if lesion is high in humerus then also loss of elbow extension
- poor grip
what is the sensory distribution of the median and ulnar nerve on the palmar surface of the hand?
- median - palmar surface of thumb, index and middle finger, half of ring finger
- ulnar - half of the ring finger and little finger
Describe the sensory innervation of the dorsal surface of the hand
- radial nerve - supplies the dorsal surface of the thumb, index, middle and half of the ring finger
- the ulnar nerve supplies the dorsal surface of the little finger and half the ring finger
