Circular Muscular Layer of Esophagus (Cervical Part)
Stratum musculare circulare oesophagi
Read moreStructure/Morphology
The circular and longitudinal muscular layers of the esophagus form the muscularis externa. The muscularis externa can be up to 300 μm thick and is composed of different types of muscle throughout its length. In the upper third, of the esophagus it is composed of skeletal muscle; the middle third is a mix of both skeletal and smooth muscle fibers; while the lower third is composed of smooth muscle only.
Key Features/Anatomical Relations
The circular muscular layer is thinner than the longitudinal layer and forms the inner layer of the muscularis externa. Superiorly, the circular layer blends with the inferior pharyngeal constrictor. Inferiorly, it’s continuous with the oblique layer of muscle in the stomach wall.
Function
The circular layer of the muscular layer of the esophagus is responsible for generating peristaltic contractions in the esophageal wall. The circumferential closure of the lumen of the esophagus pushes the swallowed bolus towards the stomach.
