Nerve Palsies in the Limbs Flashcards
What are the upper limb palsies involving the brachial plexus?
Erb’s palsy
Klumpke’s palsy
Total brachial plexus
What peripheral nerves can be affected by upper limb palsy?
Musculocutaneous Axillary Radial Median Ulnar
What are the features of Erb’s palsy?
Traction of C5, C6 (+/- C7) "waiter's tip position" - shoulder adducted and internally rotated - elbow extended and pronated - wrist flexed
What are the features of Klumpke’s palsy?
Traction of C8/T1
Very rare
Affects small muscles of hand - claw hand
What is the anatomical course of the musculocutaneous nerve?
C5, 6, 7
Lateral cord
Pierces coracobrahcialis then runs inferiorly between biceps and brachial to supply both
Gives supply to elbow joint
Terminates as the lateral cutaneous nerve to the forearm
What is Hilton’s Law?
A sensory nerve supplying a joint also supplies the muscles moving the joint and the skin overlying the insertions of these muscles
What is the anatomical course of the axillary nerve?
C5, 6 Posterior cord Wraps around surgical neck of humerus Supplies deltoid and teres minor Supplies skin over the lateral arm - regimental badge area
When might axillary nerve palsy occur?
Shoulder dislocation or fracture of the surgical neck of the humerus
What does axillary nerve palsy result in?
Deltoid atrophy
What is the anatomical course of the radial nerve?
C5, 6, 7, 8, T1
Posterior cord
Supplies triceps
Runs in the radial groove of the humerus as it passes from medial to lateral
Supplies BCR, ECRL and ERCB before dividing into PIN (motor) and SRN (sensory) branches
What is the cause of radial nerve palsy?
Entrapment or compression
What are the symptoms of radial nerve palsy?
Depend on site of lesion
Axilla - loss of elbow extension and wrist extension, and sensory changes in the forearm and hand
In arm - loss of wrist extension and sensory loss
In forearm - loss of finger extension
At wrist - loss of sensation
What does the median nerve supply?
Flexors of forearm and LOAF muscles
Sensation to radial 5 digits
What does median nerve palsy result in?
Carpal tunnel syndrome
What is the anatomical course of the ulnar nerve?
C8, T1
Medial cord
Enters forearm between two heads of FCU
Supplies medial half of FDP, FCU and all intrinsic muscles of the hand except LOAF muscles
What is the innervation of the upper limb?
Nerve roots Brachial plexus Peripheral nerves - axillary - radial - musculocutaneous - ulnar - median
What is the innervation of the lower limb?
Nerve roots Sacral and lumbar plexuses Peripheral nerves - sciatic - femoral - common peroneal - LFCN
Where can a nerve be trapped, injured or compressed?
At any point along its course, from the nerve roots as they exit the spinal canal, the plexuses they form, to the peripheral nerves
What myotome is supplied by spinal level C5?
Elbow flexors
What myotome is supplied by spinal level C6?
Wrist extensors
What myotome is supplied by spinal level C7?
Elbow extensors
What myotome is supplied by spinal level C8?
Finger extensors
What myotome is supplied by spinal level T1?
Intrinsic hand muscles
What myotome is supplied by spinal level L2?
Hip flexors
What myotome is supplied by spinal level L3?
Knee extensors
What myotome is supplied by spinal level L4?
Ankle dorsiflexors
What myotome is supplied by spinal level L5?
Long toe extensors
What myotome is supplied by spinal level S1?
Ankle plantar flexors
What are the components of the sacral plexus?
Sciatic - common peroneal nerve, tibial nerve
Lumbar plexus - femoral nerve
Ventral rami L4-S4
What does the superior gluteal nerve supply?
Gluteus medius and minimus and TFL
What does the inferior gluteal nerve supply?
Gluteus maximus
What is the main branch of the sacral plexus and what does it supply?
Sciatic nerve
L4, 5, S1, 2, 3
Supplies posterior thigh, leg and foot muscles
Made up of tibial nerve and common peroneal nerve
What is the anatomical course of the common peroneal nerve?
Wraps around neck of fibula
Divides into deep peroneal nerve which supplies the anterior compartment of the leg and the superficial peroneal nerve which supplies the lateral compartment
What does palsy of the common peroneal nerve result in?
Foot drop
What nerves are in the lumbar plexus?
L1-5
What are the main branches of the lumbar plexus?
LFCN
Femoral
Obturator
What is merelgia parasthetica?
Altered sensation and pain in the lateral thigh
Compression of the lateral femoral cutaneous nerve of the thigh as it travels under the lateral borders of the inguinal ligament
What are the components of the carpal tunnel?
Floor - carpal bones
Roof - flexor retinaculum
Contents - 4 FDS, 4 FDP, FPL and median nerve
What are the causes of carpal tunnel syndrome?
Developmental
Trauma - distal radius fracture
Swellings - ganglion, fibroma, lipoma
Inflammatory - rheumatoid, gout, TB, amyloid
Metabolic - pregnancy, mucopolysaccharides, hypothyroidism
What are the symptoms and signs of carpal tunnel syndrome?
Nocturnal pain and parasthesia in part or all of the median nerve distribution
Wasting of the thenar muscles
How would you diagnose carpal tunnel syndrome?
Look - thenar wasting, previous scars, deformity
Feel - sensation
Move - ABP power
Special tests - Tinnel’s, Phalen’s
Where is the cubital tunnel?
Between the medial epicondyle and olecranon with fascial bands from FCU forming the roof
What is the clinical presentation of cubital tunnel syndrome?
Patient has numbness of the ulnar side of the hand and has difficulty with fine tasks
Ulnar muscle wasting/claw hand/paradox
What are the ulnar muscle wasting features in cubital tunnel syndrome?
First webspace often has most marked wasting
Guttering
Hypothenar muscles
What are the ulnar claw hand features in cubital tunnel syndrome?
Hyperextension at MCJP
Flexion at IPJs
What is the ulnar paradox?
Distal lesion has worse clawing than a proximal lesion due to intact long flexors with a distal lesions
What are the key muscles tested in Froment’s test?
Adductor pollicis
Flexor pollicis longus
If ulnar nerve is not working then the patient will cheat and use FPL instead of adductor pollicis
