The mucosal lining of the cavity of the uterus is called the endometrium. It is this lining which undergoes changes over the course of the monthly menstrual cycle, sloughs off and becomes part of the menses. A biopsy of the endometrium is used to check for disease or problems of fertility.
Update Date 2/24/2014
Updated by: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.