Nerve Palsies in the Limbs Flashcards
Where can nerve palsies occur in the upper limb?
Nerve roots
Brachial plexus
Peripheral nerves - axillary, radial, musculocutaneous, ulnar, median.
Where can nerve palsies occur in the lower limb?
Nerve roots
Sacral and lumbar plexus
Peripheral nerves - sciatic, femoral, common peroneal, LFCN (lateral femoral cutaneous nerve).
What is the myotome at C5?
Elbow flexors
What is the myotome at C6?
Wrist extensors
What is the myotome at C7?
Elbow extensors
What is the myotome at C8?
Finger extensors
What is the myotome at T1?
Intrinsic hand muscles
What is the myotome at L2?
Hip flexors
What is the myotome at L3?
Knee extensors
What is the myotome at L4?
Ankle dorsiflexors
What is the myotome at L5?
Long toe extensors
What is the myotome at S1?
Ankle plantar flexors
What are some examples of nerve palsies within the Brachial plexus?
Erb’s palsy
Klumpke’s palsy
Total Brachial Plexus
What are some examples of nerve palsies within peripheral nerves of the upper limb?
Axillary nerve palsy secondary to trauma.
Radial nerve palsy secondary to compression or entrapment.
Carpal tunnel syndrome
Cubital tunnel syndrome
What is Erb’s palsy?
Paralysis of the arm due to severing of the upper trunk of C5 and C6 nerves within the brachial plexus. Usually occurs at birth during delivery.
What is the typical presentation of Erb’s palsy?
Waiter’s tip position:
- shoulder is adducted and IR
- elbow is extended and pronated
- wrist is flexed
What is Klumpke’s palsy?
Paralysis of the forearm and hand muscles due to an injury of C8 and T1 nerves within the brachial plexus.
What is the typical presentation of Klumpke’s palsy?
Claw hand
What is the path of the Musculocutaneous nerve?
Lateral cord that pierces coracobrachialis then runs inferiorly between the biceps and brachialis to supply them both. It also supplies the elbow joint.
It 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 path of the axillary nerve?
Posterior cord
Wraps around surgical neck of humerus and supplies deltoid and Teres minor. It also supplies the skin over the lateral arm - regimental badge area.
What are some examples of traumas that may cause axillary nerve palsy?
Shoulder dislocation
Fracture of Surgical neck of humerus.
What can be a sign of axillary nerve palsy?
Deltoid atrophy
What is the path of the radial nerve?
Posterior cord
Supplies the triceps in arm and runs in the radial groove of humerus as it passes from medial to lateral.
Supplies brachioradialis, extensor carpi radialis longs and extensor carpi radialis brevis, before dividing into posterior interosseous nerve (PIN) and superficial radial nerve (SRN).
What is Saturday night palsy?
Compression of the radial nerve by falling asleep with your arm hung over the back of a chair.
What is Honeymoon palsy?
Compression of the radial nerve by someone else falling asleep on your arm.
What is crutch palsy?
Paralysis of the arm/hand due to constant compression of the radial nerve, for example when using a crutch.
What are some symptoms of radial nerve palsy?
Depend on site of lesion:
Axilla - loss of elbow extension, wrist extension and sensory changes in forearm and hand.
Arm - loss of wrist extension and sensory loss.
Forearm - loss of finger extension
Wrist - loss of sensation
What is the path of the Median nerve?
Median and lateral cords
Supplies the flexors for forearm bar flexor carper ulnas and medial half of flexor digitorum profundus, and LOAF muscles.
Supplies sensation to radial 3.5 digits.
What are LOAF muscles?
Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
What is the contents of the carpal tunnel?
4 tendons of Flexor Digitorum Superficialis.
4 tendons of Flexor Digitorum Profundus.
1 tendon of Flexor Pollicis Longus
Median nerve
What makes up the roof and floor of the carpal tunnel?
Floor = Carpal bones Roof = Flexor retinaculum
What are some causes of Carpal Tunnel Syndrome?
Developmental
Trauma - distal radius fracture.
Swellings - ganglion, fibroma, lipoma.
Inflammatory - rheumatoid, gout, tuberculosis, amyloid.
Metabolic - pregnancy, mucopolysaccharidoses, hypothyroidism.
What is Carpal Tunnel Syndrome?
Nocturnal pain and parasthesia in part or all of median nerve distribution. Wasting of the thenar muscles.
Due to compression of the median nerve as it passes into wrist.
What is often present during examination of an individual with carpal tunnel syndrome?
Look - thenar wasting, previous scars, deformity (previous fracture).
Feel - sensation lost
Move - APB power reduced
Special tests - tinnels and phalens
What is the path of the ulnar nerve?
Medial cord
NO branches in the forearm.
Enters forearm between 2 heads of flexor carpi ulnaris.
Supplies medial half of Flexor digitorum profundus, flexor carpi ulnas and all intrinsic muscles in hand bar LOAF muscles.
Sensation to ulnar to 1.5 digits.
What is Cubital Tunnel Syndrome?
2nd most common nerve emtrapment.
Entraped ulnar nerve.
Cubital tunnel lies between medial epicondyle and olecranon, with fascial bands from flexor carpi ulnaris as the roof.
Patient has numbness on ulnar side of hand and difficulty with fine tasks.
What muscle wastage is present with ulnar nerve palsy?
1st webspace
Guttering (wasting of interossei)
Hypothenar wasting
What is ulnar claw hand?
Hyperextension at the MCPJ and flexion at interpharyngeal joints.
What is ulnar paradox?
When a distal lesion has worse clawing than a proximal lesion due to intact long flexors with a distal lesion.
What is Froment’s Test?
Tests the strength of adductor pollicis supplied by ulnar nerve.
Patient is asked to pinch grip something e.g a newspaper.
Test is Froment’s positive if the patient uses the FPL instead of adductor pollicis.
What is the path of the Sacral plexus?
Ventral rami of L4 to S4.
Superior gluteal nerve supplies gluteus Medius and tensor fascia latae. Inferior gluteal nerve supplies gluteus maximus.
Main branch is Sciatic nerve which supplies posterior thigh, leg and foot muscles.
What is the path of the Sciatic nerve?
Main branch of sacral plexus.
Made up of tibial nerve and common peroneal nerve.
Supplies the hamstring muscles in posterior compartment of thigh.
What is the path of Common Peroneal Nerve?
Wraps around neck of fibula.
Divides into deep peroneal nerve which supplies anterior compartment of leg, and superficial peroneal nerve which supplies later compartment of leg.
What clinical sign is present in Common Peroneal Palsy?
Foot drop - damage to peroneal nerve impairs dorsiflexion of the foot. Ability to raise foot is lost.
What are the main branches of the Lumbar plexus?
Femoral
Obturator
Lateral femoral cutaneous nerve.
What is Meralgia Parasthesia?
Compression of Lateral Femoral Cutaneous nerve of thigh as it travels under lateral border of inguinal ligament.
Results in altered sensation and pain in lateral thigh.
