Circular Muscular Layer of Stomach (Posterior)
Stratum musculare circulare gastris
Read moreStructure/ Morphology
The cross-sectional microarchitecture of the stomach demonstrates mucosa, submucosa, and muscular (inner oblique, middle circular, and outer longitudinal) layers with a thin outer serosal covering.
The circular layer is the middle layer of the muscular layer of the stomach. Its fibers are smooth muscle cells which are oriented perpendicular to the long axis of the digestive tract. Thus, the fibers wrap from lesser curvature around the body towards the greater curvature.
The circular layer is continuous with the esophagus and the thickening that forms the pyloric sphincter.
Key Features/ Anatomical Relations
The fibers of the circular layer are controlled by inputs from the vagus nerve and the myenteric nerve plexus. This plexus of enteric nerves sits between the circular layer and the outermost longitudinal layer of muscle fibers in the muscular layer (Standring, 2016).
Function
The circular layer is a layer of myofibers that contract. Together with the other muscle layers of the stomach, the fibers act to create migrating motor complexes on an empty stomach, and gastric peristalsis when food is present. The waves of gastric peristalsis grind food against the pylorus to mix and digest and pushes the digested chyme into the duodenum.
List of Clinical Correlates
- Gastroparesis
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41 edn.: Elsevier Limited.
