Lymphatics and myenteric plexus in the muscular coat in the rat stomach: a scanning electron microscopic study of corrosion casts made by intra-arterial injection.

Intra-arterially injected low viscosity methacrylate filled the lymphatic system in the muscularis externa of the young rat. Scanning electron microscopy of the corrosion casts revealed that between the inner and outer muscular coat there was a lymphatic network made up of polygonal meshes. The initial lymphatics, about 15 micron diameter drained into the thicker lymphatics, about 20-80 micron diameter. These lymphatics ran along the muscular fibers of either inner or outer layers and formed polygonal (most often rectangular) meshes. The casts of the thicker lymphatics possessed notches indicative of valve locations. The myenteric nervous plexus was also replicated between the inner and outer muscular coats. The plexus consisted of flat astral structures with primary and secondary, and occasionally, tertiary, processes which interconnected with neighboring ones. It is suggested that the enteric neurons are confined in an interconnected channel system.