Neurilemmas

Part of speech: noun

Definitions

1. Thin membranous sheaths formed by Schwann cells that wrap around the axons of nerves outside the brain and spinal cord
2. Protective outer layers surrounding peripheral nerve fibers, produced by Schwann cells and aiding nerve repair
3. Membranes enclosing the axons of peripheral nerves, each made of a Schwann cell and essential to nerve regeneration

Etymology: "Neurilemmas" is the plural of "neurilemma," the name for the thin sheath of cells that wraps around the fibres of nerves outside the brain and spinal cord. The term is a modern scientific coinage, built in English from Greek parts: "neuri-," a variant of "neuro-," from the Ancient Greek "neûron," meaning sinew, tendon or nerve, joined to "lemma," a Greek word meaning husk, rind or outer covering. The Greek "neûron" originally referred to sinew and tendon before it came to mean nerve, so the anatomist's choice of a word for a tough, fibrous cord was a return to its older sense. The "lemma" half is an unexpected pairing: the same Greek root shows up in "lemma" in its sense of a heading or premise, a meaning that came from a different ancient usage. Here the sense is simply a husk or covering, which describes the sheath exactly.

Synonyms: sheath of Schwann