Quick Facts
The lamina muscularis mucosae is the thin layer of smooth muscle fibers usually found as a part of the tunica mucosa deep to the lamina propria mucosae (Dorland, 2011).
Structure/Morphology
The muscularis mucosae is similar throughout the small and large intestine. It is the deepest part of the mucosa consisting of a very thin inner circular layer and an equally thin outer longitudinal layer of smooth muscle. Both layers tend to be thicker in the colon.
Anatomical Relations
The muscularis mucosae is the deepest part of the mucosa and adjacent to the submucosa. It has neither plicae circulares nor villi but has extensive straight tubular intestinal glands (crypts of Lieberkühn) that extend the full thickness of the mucosa (Ross and Pawlina, 2006).
Function
Contraction of the muscularis mucosae (independent of the peristaltic movement of the entire gut wall) moves the mucosa and forms ridges and depressions that facilitate absorption and movement of mucus from goblet cells to the luminal space.
List of Clinical Correlates
—Crohn's disease
—Ulcerative Colitis
—Mucosa associated lymphoid tissue (MALT) lymphoma
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Ross, M. H. and Pawlina, W. (2006) Histology: A text and atlas. Lippincott Williams & Wilkins.
