National Cancer Institute National Cancer Institute
U.S. National Institutes of Health National Cancer Institute
Dictionary of Cancer Terms
Send to Printer
sphincter

 A ring-shaped muscle that relaxes or tightens to open or close a passage or opening in the body. Examples are the anal sphincter (around the opening of the anus) and the pyloric sphincter (at the lower opening of the stomach).

Previous Definitions:sperm count, sperm retrieval, spermatic cord, SPF, sphenoid sinus
Next Definitions:spiculated mass, spinal column, spinal cord, spinal cord compression, spinal tap