Dilator muscle

Dilatator

  • Latin synonym: Musculus dilatator
  • Synonym: Dilator

Definition

Muhammad A. Javaid

A dilator muscle is a muscle that increases the diameter of an opening or lumen by pulling its margins outward. It usually acts in opposition to a sphincter muscle (or an orbicular muscle) which constricts the same aperture.

Dilator muscles may consist of skeletal or smooth muscle fibres, depending on their location and function.

Examples

  • Dilator pupillae – smooth muscle in the iris that dilates the pupil (sympathetic innervation).

  • Dilator naris – skeletal muscle that widens the nostrils (facial nerve).

References

  • Gray, H. (2016) Gray’s anatomy the anatomical basis of clinical practice. 41st edition. Edited by S. Standring. New York: Elsevier.