[Radial nerve lesions]

The radial nerve is a prolongation of the posterior secondary trunk of the brachial plexous. It goes round the posterior aspect of the humerus, and is found anteriorly at the level of the forearm where it divides into two branches: 1. A deep motor branch, the posterior interosseus nerve; and 2. A superficial sensory branch, the superficial radial nerve.

Lesions of the radial nerve are studied by conduction tests (sensory and motor) and electromyography. Sensory manifestations of lesions of the radial nerve are usually limited to the dorso-lateral area of the hand. Motor disorders are usually seen as defects of extension, in which the triceps muscle may be involved depending on the level at which the lesion occurs. When topographical criteria are considered, the clinical syndromes of the radial nerve may be classified as: 1. Neuropathies of the main trunk; 2. Neuropathies of the posterior interosseus nerve; and 3. Neuropathies of the superficial radial nerve. Trauma, external compression and trapping are the main causes of lesions in these syndromes.

The radial nerve may be involved in multi-neuropathic processes forming part of a systemic illness (vasculitis, diabetes, etc.) or of a purely neuro-muscular disorder (acute neuropathy of the brachial plexus, neuropathy due to the effect of pressure and motor multifocal neuropathy.