MUSCULAR COMPOSITION OF THE GASTRIC GROOVE IN THE GOLDEN-HAMSTER

The golden hamster possesses a forestomach and a glandular stomach. Th e gastric groove connects the cardia to the glandular stomach and is s ituated on the lesser curvature of the stomach. The constitution of th e muscle fibers in the gastric groove was investigated. The gastric gr oove consisted of two lips and a groove floor. The muscle coat of the lips was composed of a mixture of smooth and striated muscle fibers. T he smooth muscle fibers were components of the cardiac muscle loop. Th e striated muscle fibers were extensions from the esophageal inner cir cular muscle layer, and invaded about half the length of the lips. The muscle coat of the groove floor consisted of an inner circular muscle layer made up of smooth muscle fibers, and the outer longitudinal mus cle layer of the striated muscle fibers extended from the esophageal o uter longitudinal muscle layer. The present study revealed that the mu scle coat of the gastric groove in the golden hamster was composed of smooth and striated muscle fibers, and that these striated muscle fibe rs were extensions of the esophageal muscle coat.