The three muscle layers in the pyloric sphincter and their possible function during antropyloroduodenal motility

Mi-Sun Hur,Chang-Seok Oh,Seunggyu Lee,Tong Mook Kang

doi:10.1038/s41598-021-99463-x

Abstract

This study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography (micro‐CT). The stomachs of 80 embalmed Korean adult cadavers were obtained. In all specimens, loose muscular tissue of the innermost aspect of the sphincter wall ran aborally, forming the newly found inner longitudinal muscle bundles, entered the duodenum, and connected with the nearby circular bundles. In all specimens, approximately one-third of the outer longitudinal layer of the sphincter entered its inner circular layer, divided the circular layer into several parts, and finally connected with the circular bundles. Anatomical findings around the sphincter were confirmed in micro-CT images. The sphincter wall comprised three layers: an inner layer of longitudinal bundles, a middle layer of major circular and minor longitudinal bundles, and an outer layer of longitudinal bundles. The stomach outer longitudinal bundles were connected to the sphincter circular bundles. The inner longitudinal bundles of the sphincter were connected to the adjacent circular bundles of the duodenum.

Highlights

This study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography
The layer of longitudinal muscle bundles in the pyloric canal became thicker as it approached the sphincter, especially along the lesser curvature that occupied the thickest portion at the sphincter wall and became thinner as it exited the sphincter
Approximately one-third of the outer longitudinal layer of the sphincter entered its inner circular layer (Fig. 1). These bundles divided the circular layer into several parts, and ended when it connected with the sphincter circular bundles (Fig. 2)

Summary

Introduction

This study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography (micro‐CT). Loose muscular tissue of the innermost aspect of the sphincter wall ran aborally, forming the newly found inner longitudinal muscle bundles, entered the duodenum, and connected with the nearby circular bundles. The stomach outer longitudinal bundles were connected to the sphincter circular bundles. The inner longitudinal bundles of the sphincter were connected to the adjacent circular bundles of the duodenum. Goss (1973)[4] suggested that the sphincter contained some longitudinal bundles of the pyloric canal outer layer that ran inward to interlace with the ring’s circular bundles. This study was conducted to determine the muscular arrangement of the sphincter, focusing on its longitudinal bundles and their relationship with the circular bundles of the sphincter and duodenum using a Scientific Reports | (2021) 11:20094

Methods

Results

Conclusion