Oblique muscle fibers of stomach

The oblique muscle fibres of stomach constitute the innermost layer of the muscularis externa and are a distinctive feature of the stomach. These smooth muscle fibres arise mainly around the cardiac region and spread obliquely across the anterior and posterior walls of the stomach, blending with the circular muscle layer as they descend towards the pyloric region. The oblique orientation of these fibres provides an additional plane of contraction that is not present elsewhere in the gastrointestinal tract.

Working in conjunction with the circular and longitudinal muscle layers, the oblique fibres generate powerful churning and mixing movements that mechanically break down ingested food and thoroughly mix it with gastric secretions to form chyme.

Innervation

The activity of the oblique muscle fibres, like other muscular fibres in the muscular external of stomach, is coordinated by the myenteric (Auerbach's) plexus and modulated by parasympathetic fibres from the vagus nerve and sympathetic fibres from the coeliac plexus.