Peripheral nerve palsies - Upper limb Flashcards
Aetiology of Peripheral Nerve Injury
Pathophysiology of nerve compression
Nerve palsy S/S
Classification of Nerve Injury
Median nerve
Anatomy
Median nerve
Function
Thenar muscle wasting is a late sign
APB palsy is the most specific for median nerve
Lay hand flat on table and lift thumb to ceiling, do not lift thumb in a handshake position as that tests APL
Median nerve palsy
Causes
Pronator teres is high palsy
CTS is low palsy - less sensory deficit and fewer muscle involvement
Carpal bone perilunate fracture is also possible
Median nerve palsy
Clinical presentation
Special tests
5 digit dumbness is also possible due to cross innervation
More than 3.5 fingers is also compatible with CTS
Palmar cutaneous branch doesnt cross the tunnel, and true CTS only causes digital numbness and not palmar numbness
Ulnar nerve
Course
Ulnar nerve
Function
Dorsal cutaneous nerve branches before Guyons canal
So dorsal numbness is damage higher than Guyons canal, thus high ulnar nerve palsy
Causes of ulnar nerve palsy
Elbow deformities: Cubitus valgus or varus, OA, RA elbow
Cubital tunnel syndrome is most common
Guyon canal palsy: crutch users, low bicycle handle bar road cyclists
Ulnar nerve palsy
Clinical presentation
Also Jeanne sign
Compensated by MCPJ hyperextension by EPL by radial nerve
Froment sign - look for flexion of IP joint to cheat when pinching with extended IP joint
Other signs
Crossed finger test for 1st palmar and 2nd dorsal interossei weakness
Dorsal interossei palsy
Pollock test
Provocative test:
Elbow flexion test - to provoke symptoms
Tinel sign over elbow
Ulnar nerve subluxation above medial epicondyle and snapping below medial epicondyle (require surgery)
Radial nerve
Course
Radial nerve
Function
Sensory of posterior arm and dorsum
Radial nerve palsy
Causes
Radial nerve palsy
Clinical presentation
EDC test may be cheated by lumbricals supplied by median nerve
Ask patient to make a claw hand then test MCPJ extension
Erb’s palsy
Etiology
Clinical presentation
Management
Klumpke’s palsy
Cause
Signs
Brachial plexus injury
Classification
Features of pre-ganglionic lesion
Prognosis of nerve injury
Good prognostic factors
Young Age most important
Low velocity injury, sharp cut
Distal injury
Crush, high velocity, associated vascular damage are poor prognostic factors
Growth:
Nerve growth velocity is 1mm per day for distal nerve damage
Proximal nerve damage may never recover
Nerve repair
Nerve repair apart from suture
Nerve damage diagnosis
Only for ruling out other neuropathic conditions, not for diagnosis of nerve palsy
Median nerve AIN branch test
Median nerve AIN branch test
Benediction sign
Median nerve high vs low palsy
Median nerve high vs low palsy
Ulnar nerve high vs low palsy
Ulnar nerve treatment
Radial nerve high vs low palsy
Foot drop lesion causes
Deep peroneal nerve
Common peroneal nerve
Sciatic nerve
Root
Spine
Foot dorsum numbness and foot drop - likely common peroneal nerve palsy
Foot drop lesion causes
Deep peroneal nerve
Common peroneal nerve
Sciatic nerve
Root
Spine
Foot dorsum numbness and foot drop - likely common peroneal nerve palsy
L5 root vs peroneal nerve palsy
