Complex sentence: Polyneuropathies may be classified in different ways, such as by cause, by speed of progression, or by classes of polyneuropathy, in terms of which part of the nerve cell is affected mainly: the axon, the myelin sheath, or the cell body.
Split into simpler sentences: Polyneuropathies may be classified in different ways, such as by cause, by speed of progression, or by the parts of the body involved. Classes of polyneuropathy also are distinguished by which part of the nerve cell is affected mainly: the axon, the myelin sheath, or the cell body.