Longitudinal muscular layer of stomach

The longitudinal muscular layer of stomach is the outermost layer of the muscularis externa of the stomach. It consists of smooth muscle fibres that run predominantly along the long axis of the stomach, extending from the oesophagus to the pylorus. It is continuous superiorly with the longitudinal muscle layer of the oesophagus and inferiorly with that of the duodenum and is most prominent along the greater and lesser curvatures of the stomach.

Functions

The longitudinal muscular layer shortens the stomach during contraction, assisting in the propulsion of gastric contents towards the pylorus. It works synergistically with the circular and oblique muscle layers to generate peristaltic waves, churning movements, for gastric mixing, and digestion.

Innervation

• Controlled by the enteric nervous system, particularly the myenteric (Auerbach's) plexus, which lies between the circular and longitudinal muscle layers.

• It's activity is modulated by autonomic nerves, wherein the parasympathetic innervation (via vagus) stimulating motility, while sympathetic innervation (via sympathetic trunk and coeliac plexus) inhibiting motility.