neurolemma
Very LowTechnical/Specialized
Definition
Meaning
The thin outer sheath surrounding a nerve fiber (axon), particularly of peripheral nerves.
In neuroscience and anatomy, the neurolemma (also called neurilemma) is the delicate sheath that encases the myelin sheath of myelinated peripheral nerve fibers; it plays a crucial role in nerve regeneration after injury by providing a guiding pathway for regrowth.
Linguistics
Semantic Notes
The term is specific to histology and neurology. It is often used interchangeably with 'neurilemma', though some older texts distinguish neurolemma as the sheath of the axon and neurilemma as the sheath of the entire nerve. In modern usage, the terms are largely synonymous.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage. Both 'neurolemma' and 'neurilemma' are used in both varieties, with 'neurilemma' perhaps being slightly more common in general anatomical texts.
Connotations
Purely technical, with no regional connotations.
Frequency
Extremely rare outside specialized medical or biological contexts in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
The neurolemma of [nerve]Neurolemma surrounding [axon]Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None”
Usage
Context Usage
Business
Not used.
Academic
Used exclusively in advanced biology, neuroscience, and medical textbooks and research papers.
Everyday
Virtually never used.
Technical
The primary domain. Used in histology, neurology, and related medical fields to describe the structure of peripheral nerves.
Examples
By Part of Speech
adjective
British English
- neurolemma cell
- neurolemma function
American English
- neurolemma sheath
- neurolemma structure
Examples
By CEFR Level
- After the injury, the neurolemma helps guide the nerve's repair.
- The diagram clearly labels the neurolemma surrounding the axon.
- The integrity of the neurolemma is critical for successful peripheral nerve regeneration.
- Schwann cells are responsible for forming both the myelin sheath and the neurolemma.
Learning
Memory Aids
Mnemonic
Think: 'neuro' (nerve) + 'lemma' (a sheath or covering). It's the 'nerve envelope'.
Conceptual Metaphor
A PROTECTIVE TUBE or BIO-SCAFFOLDING that guides and protects the nerve's 'wiring'.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'нейролемма' (direct calque, correct but very specialized). Avoid mistranslation as 'нервная оболочка', which is a broader term (nerve sheath).
Common Mistakes
- Misspelling as 'neurolema'.
- Using it to refer to the brain's meninges (which is incorrect).
- Confusing it with 'myelin sheath', which is a different, inner layer.
Practice
Quiz
What is the primary function of the neurolemma?
FAQ
Frequently Asked Questions
The myelin sheath is a fatty, insulating layer around the axon that speeds up signal transmission. The neurolemma is the thin, outer cytoplasmic sheath (from Schwann cells) that encloses the myelin sheath in peripheral nerves.
No. The neurolemma is specific to the peripheral nervous system. Nerve fibers in the central nervous system lack a neurolemma, which is one reason they regenerate poorly after injury.
In contemporary medical and biological usage, yes, they are synonyms. Historically, there was a minor distinction, but it is no longer consistently observed.
The structure was described by 19th-century histologists. The term itself is derived from Greek (neuron = nerve, lemma = husk/sheath) and was coined in the context of early microscopic anatomy.