What are the two valves (sphincters) that enclose the small intestine at each end?

Pylorus and ileocecal valve

Explanation:

The pylorus is the sphinecter that connects the stomach with the first portion of the small intestine, the pulorus has an antrum and a canal. This valve control the gastruc flow from the stomach to the duedenum.

The ileocecal connect both intestines, this valve that connects the ileum to the cecum has an importan absorption and lymphatic functions.

explanation:

for example, code 28039 - excision, tumor, soft tissue of foot or toe, subcutaneous, 1.5 cm or greater, appears before 28043 - excision, tumor, soft tissue of foot or toe, subcutaneous; less than 1.5 cm.