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
