Radial nerve paralysis

Radial nerve paralysis is a primary cause of lameness is an uncommon condition that results in the inability to extend the elbow, carpus and digit.

Other brachial plexus nerves include the radial nerve, which arises from spinal cord segments C7 to T2. The inability of an animal to extend its carpus and digit is caused by distal radial paralysis. The elbow, carpus, and fetlock (metacarpophalangeal joint) of an animal cannot extend to bear weight when it has proximal radial nerve paralysis, which is clinically difficult to distinguish from brachial plexus injury.

Etiology

Stretching too closely to the brachial plexus can harm the proximal radial nerve, which could impair the triceps muscles, as well as the extensors of the carpus and digits. The injury is commonly linked to casting an animal with ropes or to any circumstance in which the animal unintentionally restrains its forelimb and then tries to wrest it free violently. In exceptionally hefty animals, persistent recumbency can lead to distal radial paralysis.

• In most cases, paralysis of the radial nerve is due to trauma of the shoulder region caused by hyperextension of the forelimb or extreme abduction of the shoulder.
• Fractures of the humerus, the seventh cervical, and first thoracic vertebrae can result in radial nerve paralysis.
• Tumors, abscesses, and enlarged axillary lymph nodes that occur in the cranial thoracic region along the course of the nerve and tumors of the brachial plexus and radial nerve themselves may also result in radial paralysis.
• There have been isolated reports of radial paralysis included
• in a generalized distal axonalopathy.
• Prolonged lateral recumbency while under general anesthesia on an operating table or while on the ground may also produce a radial-paralysis like syndrome in the forelimb next to a hard surface.
• Episodes of ischemia are likely to cause neuropractic conduction changes and permanent nerve changes if prolonged.

Diagnosis

• History and clinical signs
• Radiography evaluation
• Ultrasonographic examination
• Laboratory analysis of muscle enzyme
• Electrophysiological studies like electromyography

Treatment

• Anti-inflammatory therapy– NSAID and low dose of corticosteroids during acute phase
• Stall rest
• Application of bandage splint
• Controlled exercise
• Topical application of cold therapy, DMSO or surpass in the presence of external swelling