Basics: Aetiology, Pathophysiology, General Symptomatology and Diagnosis of Peripheral Nerve Injuries

An injury to a peripheral nerve may cause life-long functional disabling deficits, and have a considerable impact on the patient’s quality of life. After a nerve injury outside the central nervous system, numerous reactions are initiated in the chain of neurones from the brain to the muscles and the peripheral receptors. In 1941 Cohen introduced a classification system that was later popularised by Seddon [1]. Sunderland extended the system in 1951 with the definition of five degrees to describe the severity of the injury to the nerve [2]. The classification is based on the normal anatomy of the nerve. Finally MacKinnon added one more pattern of pathology in 1988 introducing the partial lesion, often described as a sixth degree of nerve injury [3]. The classification is illustrated in Table 5.1.1.