Muscularis mucosae

The lamina muscularis mucosae (or muscularis mucosae) is a thin layer of muscle of the gastrointestinal tract, located outside the lamina propria mucosae and separating it from the submucosa. It is present in a continuous fashion from the oesophagus to the upper rectum (the exact nomenclature of the rectum’s muscle layers is still being debated). A discontinuous muscularis mucosae-like muscle layer is present in the urinary tract, from the renal pelvis to urinary bladder; as it is discontinuous it should not be regarded as a true muscularis mucosae.