Nerve Palsies in the Limbs Flashcards
Describe the brachial plexus?
From spinal roots C5-T1 > upper, middle and lower trunk > anterior/posterior divisions > medial/lateral cords > branches
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Brachial lesions are common in what?
Childbirth
Upwards traction (such as fall onto side of neck - upper cord damage)
Downwards traction - lower cord damage
Damage to what spinal nerves is considered upper cord damage?
C5, C6
What muscles are supplied by the upper cords (C5, C6)?
Deltoid
Shoulder muscles
Brachialis
Biceps
What kind of paralysis does upper cord damage cause?
Erb-Duchenne paralysis (porters tip)
Describe Erb-Duchenne paralysis?
- Causes Erb-Duchenne paralysis (arm “porters tip”)
- Arm adducted, elbow extended, forearm pronated, wrist flexed
Damage to what spinal nerve is lower cord damage?
T1
What paralysis does lower cord damage cause?
Klumpke’s palsy
Axillary nerve is formed from what spinal nerves?
C5, C6
What cord forms axillary nerve?
Posterior cord
What does the axillary nerve supply?
wraps around surgical neck of humerus supplying
- deltoid
- teres minor
- regimental badge area of skin
Damage to axillary nerve causes what paralysis?
Axillary nerve palsy
What is the presentation of axillary nerve palsy?
- Lack of sensation in badge area
- Deltoid atrophy
What often causes axillary nerve palsy?
- shoulder dislocation
- fracture of surgical neck of humerus
Radial nerve is formed from what spinal nerves?
C5, C6, C7, C8, T1
Radial nerve comes from what cord?
Posterior cord
What does the radial nerve supply?
- tricep brachii
- supplies brachoradialis (BCR), extensor carpi radialis longi (ECRL) and extensor carpi radialis brevis (ECRB)
- before dividing into posterior interosseus nerve (PIN) (motor) and superficial radial nerve (SRN) (sensory) branches
Describe the course of the radial nerve?
- Runs in radial groove of humerus as it passes from medial to lateral
Radial nerve damage causes what paralysis?
Radial nerve palsy
What is the presentation of radial nerve palsy?
- loss of extension in digits and wrist, forearm supinators
- sensory changes in forearm and hand
What often causes radial nerve palsy?
- entrapment (maybe in radial fracture)
- compression (such as due to Saturday night palsy)
What nerve supplies snesation to this area?
Radial nerve
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Median nerve is supplied from what spinal nerves?
C5, C6, C7, C8 and T1
What cords form the median nerve?
Medial and lateral cords
What does the median nerve supply?
- Supplies flexors of forearm, LOAF muscles
- Supplies sensation to radial 3.5 digits
What nerve supplies this area?
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Median nerve
What forms the floor and the roof of the carpal tunnel?
- Floor
- Carpal bones
- Roof
- Flexor retinaculum
What are the contents of the carpal tunnel?
9 tendons and a nerve
- flexor digitorium superficialis (FDS x 4)
- flexor digitorium profundus (FDP x 4)
- flexor pollicus longus (FPL)
- median nerve
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What are some causes of carpal tunnel syndrome?
- development
- trauma: distal radius fracture
- swellings: ganglion, fibroma, lipoma
- inflammatory: rheumatoid, gout, TB, amyloid
- metabolic: pregnancy, mucopolysaccharidoses, hypothyroidism
Carpal tunnel syndrome involves what nerve?
Median nerve
What is the presentation of carpal tunnel syndrome?
- nocturnal pain
- parasthesia in part or all of median nerve distribution
- wasting of the thenar muscles
- lack of sensation
What investigations are done for carpal tunnel syndrome?
- Tinnels test
- Phalens test
Whats the treatment of carpal tunnel syndrome?
- splints
- treat metabolic cause
- steroid injection
- surgery: divide roof of carpal tunnel to relieve pressure
Ulnar nerve is formed from what cord?
Medial cord
Does the ulnar nerve supply any muscles in the arm?
- No branches in arm
Ulnar nerve enters the forearm between what?
two heads of flexor carpi ulnaris (FCU)
Ulnar nerve supplies what?
- medial half of flexor digitorium profundus (FDP), flexor carpi ulnaris (FCU) and all intrinsic muscles in hand apart from LOAF
- sensation to ulnar 1.5 digits
What nerve supplies this area?
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Ulnar nerve
Ulnar nerve runs through what tunnel?
Cubital tunnel
Where is the cubital tunnel?
medial epicondyle and olecranon with fascial bands from flexor carpi ulnaris (FCU) as roof
Cubital tunnel syndrome involves what nerve?
Ulnar nerve
What is the presentation of cubital tunnel syndrome?
- Numbness on ulnar side
- Difficulty with fine tasks
What is the presentation of ulnar nerve palsy?
motor deficit: claw hand & hypothenar and first dorsal interosseus wasting
sensory deficit: little finger
What investigation is done for ulnar nerve palsy?
- Froment’s test
- Tests adductor pollicis (ulnar nerve) and flexor pollicis longus (median nerve)
- If ulnar nerve not working, patient will cheat and use FPL instead of adductor pollicis
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What does the Froment’s test test?
- Tests adductor pollicis (ulnar nerve) and flexor pollicis longus (median nerve)
- If ulnar nerve not working, patient will cheat and use FPL instead of adductor pollicis
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What are the roots of the lateral femoral cutaneous nerve?
L2, L3
Describe the course of the lateral femoral cutaneous nerve?
Lies on surface of iliacus muscle, usually exits pelvis under lateral end of inguinal ligament but can vary
What does the lateral femoral cutanoeus nerve supply?
Purely sensory to lateral aspect of thigh
Compression of the lateral femoral cutaneous nerve causes what?
meralgia paraesthetica
What supplies this area?
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Lateral femoral cutaneous nerve
What is the treatment for lateral femoral cutanoeus nerve palsy?
- Steroid injection guided by US
- Operation to release tunnel
What are the roots of the sciatic nerve?
L4-S3
What is the largest nerve in the body?
Sciatic nerve
Describe the course of sciatic nerve?
- Exits through sciatic foramen below piriformis muscles
- Runs deep to gluteus maximus muscle
What does the sciatic nerve supply?
- Hamstring (posterior)
- Part of adductor magnus
- All lower leg and foot muscles via terminal branches (tibial and common fibular nerves)
What can damage to sciatic nerve occur due to?
- Posterior dislocation of hip
- Intra-muscular injections
- During surgery or trauma
What roots supply the common fibular nerve?
L4-S2
What is the common fibular nerve a branch of?
Smaller and lateral branch of sciatic nerve:
- Passes around lateral aspect of neck of fibula
- Divides into superficial and deep fibular nerves
Deficits to common fibular nerve causes what?
Deficit causes foot drop and slapping gait
What is the most commonly injured nerve in the leg?
Common fibular nerve