Disorders of peripheral nerves

Abstract

The peripheral nervous system involves all nerves lying outside the spinal cord and brainstem except the olfactory and optic nerves that are extensions of the central nervous system itself. All peripheral nerve axons are invested either with a wrapping of myelin made by Schwann cells (myelinated nerve) or by cytoplasm of Schwann cells (unmyelinated nerve). The chapter begins with a discussion of common major clinical features and mechanisms of damage of all motor and sensory nerves. Three common diseases of peripheral nerves are then discussed in detail: diabetic distal symmetrical polyneuropathy, carpal tunnel syndrome, Bell’s palsy or idiopathic peripheral facial nerve palsy, with attention to their pathophysiology, major clinical features, major laboratory findings, and principles of management and prognosis.