peripheral nerves Flashcards
30 yo woman– motor vehicle accident. slams her left shoulder into the steering wheel, unable to extend and suppinate the left arm, and has decreased sensation on the posterior aspect of the upper arm, forearm and hand. What nerve is likely injured? what motor injuries? what sensory loss?
radial– innervates posterior muscles of the arm and forearm.
- loss of extension at the elbow, wrist and digits, weakened extension at the shoulder, and weakened supination
- sensory loss on posterior arm, forearm, and hand
shoulder dislocation can lead to which nerve injuries?
radial nerve or axillary nerve
axillary nerve- supplies which muscles? injury leads to…?
deltiod and teres minor
-injury = loss of abduction of the arm in the horizontal plane
how is axillary nerve typically damaged?
fracture of the surgical neck of the humerus or dislocation of the shoulder
median nerve- what does it innervate?
muscles of the ant. comp. of the forearm EXCEPT carpi ulnaris and half of the flexor digitorum profundus (it supplies the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor pollicis longus, pronator quadratus, abductor pollicis brevis, opponens pollicis, superficial head of the flexor pollicis brevis, the 1st and 2nd lumbricals, and half of the flexor digitorum profundus)
injuries of the median nerve at the elbow and wrist cause clinical problems with respect to
the forearm, wrist and hand mainly with flexion and pronation. Weakened extension and weakened supination
musculocutaneous nerve innervates…
injury to musculocutaneous nerve causes…
muscles of anterior arm
injury: loss of elbox flexion, weakness in supination and loss of sensation on lateral aspect of forearm
ulnar nerve innervates… clinical problems arise at what level?
muscles of the forearm not innervated by median nerve, and all the muscles of the hand except those innervated by median (flexor carpi ulnaris, palmaris brevis, abductor digiti minimi, flexor digiti, minimi brevis, opponens digiti minimi, palmar and dorsal interossei, 3rd and 4th lumbricals, medial half of the flexor digitorum profundus). Clinical problems arise with injury at the elbow and wrist
what peripheral nerve disease frequently follows viral ifxn, and has rapidly evolving limb weakness with symmetric hyporeflexia but normal sensation. (sensory symp can occur, but motor symp predom). the symptomes typically ascend the body —> may evolve into complete paralysis with resp failure. It can be an autoimmune disease and is correlated to demyelination…
Guillain-Barre syndrome
damage to which peripheral nerve might cause wrist drop?
radial nerve!
the radial nerve provides sensation to what part of the hand?
the dorsal aspect of the radial side of the hand, including all the fingers (except the part around the fingernails, half the ring finger and the little finger)
the ulnar nerve provides sensation to what part of the hand?
dorsal and palmar part of small finger and half of the ring finger
the median nerve provides sensation to what part of the hand?
palmar aspect of the hand, digits 3, 4 and 5 plus half ofthe ring finger, the nail beds of all those fingers on the dorsal side
is palm sensation affected by carpal tunnel syndrome- why or why not?
no, because the superficial palmar cutaneous branch of the median nerve passes superficial to carpal tunnel
injury to the radial nerve can cause…
wrist drip and sensory loss of the proximal part of the dorsal aspect of the thumb/digits 3,4 and 1/2 of 2
