Peripheral Nerve Palsy Flashcards
What examination can be done to test for Carpal Tunnel Syndrome?
Tinel’s Test- Tap over carpal tunnel
Phalen’s Test- Flex the wrist for 60 seconds
What are symptoms of carpal tunnel syndrome?
Pain and tingling in the thumb, index finger, middle finger and lateral side of the ring finger on the palmar side
Describe the sensory innervation of the hand
Median nerve- palmar side of thumb, index finger, middle finger and lateral ring finger
Ulnar nerve- palmar side of medial ring finger and little ring and same on back of the hand
Radial Nerve- Dorsal surface of the thumb, index finger, middle finger and lateral half of ring finger
What is seen on examination of patients with carpal tunnel syndrome?
Wasting of the thenar muscles
Sensory reduction on palmar surface of thumb, index finger, middle finger and lateral third of ring finger
Weakness of abductor pollicis brevis
Note- nerve branch from median nerve supplies the palm and this does not pass through the tunnel so sensation is not altered there
What are the boundaries of the carpal tunnel?
Roof- Flexor Retinaculum
Floor- Carpal bones
What are the carpal bones?
Some Lovers Try Positions That They Cant Handle
Scaphoid Lunate Triquetrum Pisiform Trapezoid Trapezium Capitate Hamate
What causes carpal tunnel syndrome?
Compression of the median nerve- may be due to: Idiopathic Inflammation XS GH- Acromegaly Hypothyroidism Diabetes Rheumatoid arthritis (joint inflammation) Osteoarthritis Pregnancy- often settles after delivery
How is carpal tunnel syndrome investigated?
Nerve conduction studies- reduced conduction rate.
What is the management for carpal tunnel syndrome?
Reduce typing
Wrist splints
Local steroid injections
Decompression surgery- incision in flexor retinaculum
How does ulnar nerve irritation commonly present?
Paresthesia/ reduced sensation/ pain in the little finger and medial side of ring finger on palmar side
What does the median nerve innervate?
Flexor and pronator muscles in the anterior compartment of the forearm (except for flexor carpi ulnaris which is innervated by the ulnar nerve)
Thenar muscles
Lateral two lumbricals
What are the nerve roots of the median nerve?
C6 to T1
What are the motor innervations of the ulnar nerve?
All the intrinsic muscles of the hand (except for the lateral two lumbricals and thenar muscles- median nerve)
Flexor carpi ulnaris
Medial half of flexor digitorum profundus (flexes ring and little finger at DIP)
What might be seen for an ulnar nerve lesion?
Reduced sensation over palmar/dorsal surface of the little and medial side of ring ringer
Wasting of muscles of hand with thenar sparing
Ulnar claw- due to weakness of the intrinsic muscles of the hand which flex the MCP and extend the IPs- does causes long flexors and extensors to take over (in the forearm). Note if at the elbow there is loss of supply to the medial half of flexor digitorum profundus causing extension of the DIP of ring and little ringer.
What causes damage to the ulnar nerve?
Lacerations at the wrist Fractures at the elbow Compression at the elbow Dislocation at the elbow Osteoarthritic changes at elbow
What investigation should be done for ulnar nerve palsy?
Nerve conduction studies
What clinical sign can test for ulnar nerve palsy?
Froment’s sign- paralysis of adductor pollicis- can’t hold paper between thumb and index finger
What muscles are innervated by the median nerve?
Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
(LOAF)
What does muscles does the radial nerve innervate?
Triceps
Extensor muscles in the forearm
What does a lesion of the radial nerve cause?
Wrist drop
Inability to extend the fingers at the MCP due to weakness of extensors in the forearm
Where does the radial nerve provide sensory innervation to?
Posterior of the forearm
Dorsal surface of thumb, index finger, middle ringer and lateral half of ring finger
Lots of overlap so check the web space between thumb and index finger)
What muscles does the radial nerve innervate?
Triceps
Brachioradialis
Extmespr carpi radialis longus
What can cause radial nerve injury?
Fracture of the humeral shaft- radial nerve passes in the radial groove Shoulder dislocations (also causes weakness of the triceps) Crutch trauma at the level of the axilla
What does a common peroneal nerve palsy cause?
Foot drop- if permanent causes a high stepping gait.
Also weakness in eversion
