Muscular architecture and manometric image of gastroesophageal barrier in the rat

The two components of the gastroesophageal barrier, the sphincter and the c rural sling, closely overlap in humans, whereas they are widely separated i n the rat. This investigation correlates the anatomical components of the b arrier and their manometric counterparts in this animal. Sphincteric and cr ural sling pressures were measured in four quadrants in 23 rats, Muscle thi ckness was measured at nine levels of the gastroesophageal junction in the same quadrants in 12 rats and the muscular architecture of the region was s tudied in 10 fresh specimens. The manometric sphincteric component is stron ger on the right side where the thickest muscle fibers anchor to the anteri or and posterior borders of a mucosal ridge that almost surround the cardia , Conversely, the sling pressure is highest towards the left where the musc ular bundles straddle the esophagus, In conclusion, there is a close corres pondence between the manometric image and the muscular architecture of the components of the gastroesophageal barrier in the rat, The anatomical arran gement of U-shaped muscular bundles oriented in opposite directions creates a particularly powerful antireflux mechanism.