Neurilemma

Neurilemma (also known as neurolemma, sheath of Schwann, or Schwann's sheath)^[1] is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurilemmocytes) that surrounds the axon of the neuron. It forms the outermost layer of the nerve fiber in the peripheral nervous system.^[2]

Neurilemma
Diagram of longitudinal sections of medullated nerve fibers.
Cross section of an axon. 1. Axon 2. Nucleus of Schwann cell 3. Schwann cell 4. Myelin sheath 5. Neurilemma
Details
System	Peripheral nervous system
Location	Schwann cell
Identifiers
MeSH	D009441
TH	H2.00.06.1.00002
Anatomical terms of microanatomy [edit on Wikidata]

The neurilemma is underlain by the myelin sheath (also known as the medullary sheath). In the central nervous system, axons are myelinated by oligodendrocytes, thus lack neurilemma. The myelin sheaths of oligodendrocytes do not have neurilemma because excess cytoplasm is directed centrally toward the oligodendrocyte cell body.

Neurilemma serves a protective function for peripheral nerve fibers. Damaged nerve fibers may regenerate if the cell body is not damaged and the neurilemma remains intact. The neurilemma forms a regeneration tube through which the growing axon re-establishes its original connection.

Neurilemoma is a tumor of the neurilemma.^[1]