Radial Nerve Palsy

Radial nerve palsy produces an inability to extend the metacarpophalangeal joints, owing to paralysis of the extensor digitorum communis muscle. However, the lumbrical and interossei muscles, which are served by the median and ulnar nerves and insert into the dorsal expansions (extensor hoods) of the proximal phalanges, are able simultaneously to flex the metacarpophalangeal joints and to extend the interphalangeal joints [thus not answer d ]. Also, abduction of the digits, a function of the dorsal interossei, and adduction, a function of the palmar interossei, are both mediated by the ulnar nerve and, therefore, unaffected [thus not answers a and b].

Low radial nerve palsy occurs when the radial nerve is injured at the level of elbow, so that the muscles supplied by the radial nerve in the distal arm (Brachioradialis and Extensor Carpi radialis longus) are spared.

Ref: Essential Orthopedics By J Maheswari, 3nd Edition, Page 53; Apley’s System of Orthopaedics and Fractures By Louis Solomon, 9th Edition, Chapter 11, Page 282

A i.e. Loss of nerve supply to brachoradialis

– Mnemonic – “TAB Long radial muscle” i.e. Triceps, Anconeus, Brachialis and Brachioradialis & Extensor carpi radialis longus muscles are spared in low radial nerve lesions (i.e. lesions below the level of elbow.)

– Lateral & posterior cutaneous nerves of arm and posterior cutaneous nerve of forearm are also spared in low radial nerve lesions.

A i.e. Extensor carpi radialis longus 

Extensor carpi radialis longus muscle is supplied by main trunk of radial nerve above the level of elbow joint; whereas extensor carpi radialis brevis, finger extensors (extensor indics, extensor digitorum, extensor digits minimi) are supplied by its posterior interosseous branch and sensation on dorsum of hand by superficial radial branch below the level of elbow joint.

Ans. is ‘a’ i.e., Radial nerve palsy

Splints

• Any material which is used to support a fracture is called splint.
• Splints are used for immobilizing fractures; either temporarily during transportation or for definitive treatment.
• The most commonly employed splints is plaster of paris (POP) splint. Various POP splints are.

1. Casts : – Here the POP roll completely encircles the limb.
2. Slab : – It is not completely encircles the limb, but only one half or one third circumference.
3. Spica : – This encircles a part of the body; e.g., hip spica for fractures around hip.

Ans. is ‘a’ i.e., Radial nerve palsy

Ans. is ‘a’ i.e., Radial nerve palsy

Complications of humerus shaft fracture

1. Nerve injury : – Radial nerve is the most commonly injured nerve in fracture shaft humerus. It is particularly common in oblique fractures at the junction of middle and distal third of the bone (Holstein- Lews fracture).
2. Vascular injury : – Brachial artery damage.
3. Delayed union or non-union : – Delayed union or non-union may occur, especially in transverse fracture of the midshaft. The cause of non-union is distraction at fracture site due to gravity and weight of plaster.
4. Joint stiffness : – Shoulder & elbow stiffness.