Nerve injuries and palsies in the limbs Flashcards
What are common causes of brachial plexus lesions
During birth when the child is pulled out of a tight space
During injuries - commonly driving accidents or falling onto the shoulder
Describe porters tip and what causes it
Erb-duchenne paralysis Arm is adducted because deltoid is not working
Elbow is extended due to bicep not working correctly
Forearm is abducted and wrist is flexed
What happens in upward traction brachial plexus lesions
Klumpke’s palsy
What cord does the axillary nerve come from
posterior cord
Why does the axillary nerve get damaged during dislocations and fractions of the surgical neck of the humerus
It wraps around the surgical neck of the humerus normally
What does the axillary nerve supply
deltoid and teres minor
What is the test on examination to see if there is damage to the axillary nerve
Feel the regimental badge area on the shoulder and if there is no sensation, the axillary nerve is damaged
What are common causes of radial nerve palsy
entrapment and compression
What is saturday night palsy and what does it cause
Sitting with arm over chair and chair compresses radial nerve
What do the symptoms of the radial nerve palsy depend on
The site of the lesion
If the radial nerve palsy is more proximal at the axilla what happens
Every function distal to that is compromised
What happens if the radial nerve palsy is at the axilla
Loss of elbow extension, wrist extension and sensory changes inthe forearm and hand
What happens if the radial nerve palsy is at the arm
Loss of wrist extension and sensory loss
What happens if the radial nerve palsy is at the forearm
Loss of finger extension
What happens if the radial nerve palsy is at the wrist
Loss of sensation - damaging superficial radial nerve
What is the area that is normally checked for sensation in radial nerve injury
Dorsal aspect of first webbing between index finger and thumb
What is the contents of the carpal tunnel
4 Flexor digitorum superficialis tendons
4 Flexor digitorum profundus tendons
1 flexor pollicis longus tendon
Median nerve
What are the causes of carpal tunnel syndrome
Trauma, swelling, inflammation and metabolic conditions where there is swelling in the joint
How does carpal tunnel syndrome present
Nocturnal pain and parasthesia in the median nerve distribution (index finger, thumb and half of middle finger )
Wasting of the thenar muscles
What is checked in the movement for carpal tunnel syndrome
Movement - Abductor pollicis brevis power
What are the tests done on examination for carpal tunnels syndrome
Tinnels
Phalens
Describe tinnels test
tapping the middle of the carpal tunnel with the middle finger - this will cause shooting sensations into middle finger if the patient has carpal tunnel syndrome
Describe phalens test
Putting the back of the hands together – the opposite of prayer sign – same pain and paresthesia as the night symptoms if they have carpal tunnel
What is the treatment for carpal tunnel syndrome
Carpal tunnel release - removing the roof of the carpal tunnel to relieve the pressure on the median nerve
What is the sensory supply of the ulnar nerve
hypothenar eminence, little finger and half of the ring finger
Where is the normal place of compression for the ulnar nerve
cubital tunnel syndrome
What is the cubital tunnel
Runs between the medial epicondyle and olecranon with fascial bands of flexor carpi ulnaris on top of it (the area which is thought to be the funny bone)
How does cubital tunnel syndrome present
Numbness on the ulnar side of the hand
How does ulnar nerve palsy present
Wasting of muscles - first web space first usually and the hypothenar
Claw hand can occur in significant nerve compression
What is ulnar claw hand
Flexion at the ulnar interphalangeal joints and hyper extension at the metacarpal phalangeal joints
What is a test for ulnar nerve
Froment’s test - checking adductor pollicis
Describe froment’s test
Ask patient to hold a piece of paper while their thumb is up and there other digits are in a fist - if there is ulnar nerve damage, the adductor pollicis won’t be working so they will bend their thumb using flexor pollicis longus which is supplied by the median nerve
What are the nerve roots of the lateral femoral cutaneous nerve
L2-3
Describe location of lateral femoral cutaneous nerve
Lies on surface of iliacus muscle - exits pelvis under lateral end of inguinal ligament
What does the lateraql femoral cutaneous nerve supply
Sensory innervation to lateral aspect of the thigh
How does the lateral femoral cutaneous nerve compression occur
It runs through a tunnel so it can become compressed
What is the treatment of lateral femoral cutaneous nerve compression
Injecting steroids into the tunnel to reduce the swelling
Operation can be done if steroids do not work and to open up the tunnel and release the pressure
What is the root of the sciatic nerve
L4-S3
Where does the sciatic nerve leave the pelvis
Sciatic foramen below the priformis muscle
What does the sciatic nerve supply
Hamstring muscles (posterior) - part of adductor magnus and all of the lower leg and foot muscles through terminal branches - tibial and common fibular nerves
What is the roots of the common fibular nerve (commonly known as peroneal nerve)
L4-2 - small branch of the sciatic nerve
What happens if there is damage to the common fibular nerve
Footdrop and slapping gait
What is slapping gait - foot cant dorsiflex so patients have to lift legs higher and the foot slaps when they plant the foot down
