PERIPHERAL NERVE INJURIES

Classification of nerve injury

WALLERIAN DEGENERATION The degenerative changes the distal segment of a peripheral nerve fiber (axon and myelin) undergoes, REGERNERATION Regrowth of the axon will take place down the endoneurial tube. Regeneration of the axon will grow at the rate of 1-2 mm/day.

AXILLARY NERVE (C5 – C6)INJURY Loss of deltoid contour and greater tuberosity prominent. Clinical features: inability to abduct the arm because of the paralysis of the deltoid and teres minor. Muscle wasting, can be observed by the loss in contour over the shoulder. Sensory loss is minimal and seen in the lower half of the muscle

Radial Nerve Injuries Wrist Drop Injuries to the Radial Nerve in the Axilla: In the axilla- Crutch palsy, Saturday night palsy It can also be badly damaged in the axilla by fractures and dislocations of the proximal end of the humerus. Motor The triceps, the anconeus, and the long extensors of the wrist are paralyzed. The patient is unable to extend the elbow joint, the wrist joint, and the fingers. Deformity : Wristdrop Wrist Drop

Injuries to the Median Nerve at the Wrist Median Nerve Injuries Injuries to the Median Nerve at the Wrist Motor: The thumb is laterally rotated and adducted. The hand looks flattened and “ape-like.” Opposition movement of the thumb is impossible. The first two lumbricals are paralyzed, Ape thump deformity

Carpal Tunnel Syndrome it is an entrapment neuropathy caused by compression of median nerve in the carpal tunnel, in middle aged women . cause is idiopathic in most patients clinical features . pain , numbness , tingling or an " electric shock " feeling in thumbs and finger supplied by the median nerve.

The condition is usually bilaterally sometimes sensory loss of radial three and half digits weakness and wasting of abductor pollicis brevis Tinel's sign : tapping on the carpal tunnel produces pain Diagnosis diagnosis is clinical confirmed by nerve conduction velocity (NCV) that shows slowing of conduction over the wrist Management : 1. Rest 2. Splinting at night 3. Local injection of corticosteroid 4. IF pregnancy is the cause - give diuretics 6.Surgical decompression of the nerve in carpal tunnel if all above measures fail

Ulnar Nerve (C8, T1) Injuries Muscles paralyzed – Flexor carpi ulnaris, Hypo thenar muscles and Adductor pollicis Sensory loss – Medial 1 ½ fingers Deformity – Claw hand Claw Hand Sensory Loss

Common Peroneal Nerve Injury Muscles paralyzed – Ankle Dorsiflexors and Foot Evertors. Sensory loss – Loss of sensation occurs down the anterior and lateral sides of the leg and dorsum of the foot and toes Deformity – Foot drop (Plantar flexion of Ankle and Inversion of foot) Gait : Foot drop gait ( In adequate foot clearance during swing phase, so the patient compensates with excessive Hip flexion. So it is also called High stepping gait) Foot Drop or High Stepping Gait

Diagnostic tests EMG SD curve Nerve Conduction Studies Tinel’s sign Sweat test Skin resistance test

Principles of treatment To prevent or reduce oedema Positioning, Active movements, Massage, To prevent contractures Passive movements to full joint ROM Splints. To maintain activity and power of unaffected muscles Facilitate movement by supporting limb or functional splinting Electrical stimulation by Interrupted Direct Current (IDC) Encourage use of unaffected muscles in the limb To look after areas where there is any sensory disturbance Care for areas of anaesthesia

Splints Knuckle Bender Splint for Claw Hand (Ulnar Nerve) Cockup Splint for Wrist Drop (Radial Nerve) Ankle Foot Orthosis for Foot Drop (Common Peroneal Nerve)