fasciculus

IPA/fæsˈɪ.kjə.ləs/
IPA/fæsˈɪ.kjə.ləs/

fasciculus — noun

  • fasciculussingular
  • fasciculiplural

1. a narrow group of muscle or nerve fibers tied together inside the body — for exa

1.nounC2
Definition

a narrow group of muscle or nerve fibers tied together inside the body — for example, the small bundles you can see when a piece of meat is sliced lengthwise.

Example

The medical student traced one fasciculus along the patient's forearm during dissection class.

typical singular usage in anatomy class

Each fasciculus in the spinal cord carries signals between the brain and a specific body region.

collocation: fasciculus in the spinal cord

Common collocations
  • nerve fasciculus
  • muscle fasciculus
  • damaged fasciculus
  • fasciculus of the spinal cord
Synonyms
  • fascicle

    everyday medical synonym; identical meaning, shorter form preferred in clinical writing

  • fiber bundle

    plain-English description; used when explaining the term to non-specialists

  • tract

    used specifically for long fasciculi of nerve fibers inside the central nervous system

Grammar Patterns

a fasciculus of [nerve/muscle] fibers

Usage Note

Almost exclusively medical or anatomical writing; the plural is 'fasciculi' (Latin plural), rarely 'fasciculuses'. In everyday English, 'bundle' or 'fascicle' is used instead.

Common Mistakes

My arm has a lot of fasciculus.
My arm has many muscle fibers grouped into fasciculi.
'fasciculus' is countable; use the plural 'fasciculi' for more than one.
The book has three fasciculus.
The book has three fascicles.
'fasciculus' in modern English means a fiber bundle in the body, not a part of a published book.

Word family

  • fascicle
    nounC2
  • fascicular
    adjectiveC2
  • fasciculation
    nounC2

Synonym discussion

Sense: noun/1

All four words describe a group of nerve or muscle fibers gathered together, but they differ in register and scope. 'Fasciculus' is the Latin form preferred in formal anatomy textbooks and in named structures, such as the medial longitudinal fasciculus. 'Fascicle' is its everyday medical equivalent: shorter, more common in clinical notes, and used for both nerve and muscle groupings. 'Tract' is more specialized, naming long fiber pathways inside the brain or spinal cord, such as the spinothalamic tract. 'Bundle' is the plain-English word, used when speaking to patients or in introductory biology lessons. For example, a doctor might say 'a nerve bundle' to a worried patient but write 'a fasciculus of the dorsal column' in the surgical report.

Common collocations

Nouns

Phrases

  • medial longitudinal fasciculus
  • arcuate fasciculus

Prepositions

Etymology

LatinEnglish

Borrowed from Latin 'fasciculus', meaning 'a small bundle', the diminutive of 'fascis' ('bundle, bunch'). The Romans used the word for small bundles of sticks or papers. English took it up in the seventeenth century, first for a small published booklet (like one part of a multi-volume work) and later, in the nineteenth century, for the small fiber groups seen by anatomists under early microscopes. The publishing sense is now rare; the anatomical sense dominates modern use.