endometrium
Meaning of endometrium: The endometrium is the inner lining of the uterus that thickens and sheds each menstrual cycle and supports a pregnancy if one occurs.
Definition of endometrium
The endometrium is the layer of tissue that lines the interior of the uterus. It consists of glands and specialized tissue that respond to hormonal signals, thickening during each menstrual cycle in preparation for a possible pregnancy.
If pregnancy does not occur, the outer portion of the endometrium is shed during menstruation, and the cycle of thickening and shedding begins again. If a fertilized egg implants, the endometrium instead continues to develop to support the early pregnancy.
The thickness and appearance of the endometrium, often assessed by ultrasound, can vary normally across the menstrual cycle and across different life stages, and abnormal thickening or bleeding involving the endometrium is evaluated for a range of possible causes, including polyps, hyperplasia, and, less commonly, cancer.
Used in a sentence
Ultrasound was used to measure the thickness of the endometrium in the postmenopausal patient.
Good to know
The endometrium is the inner lining of the uterus, while the myometrium is its muscular wall, a distinction that matters because conditions such as endometrial polyps and endometrial hyperplasia specifically involve the lining rather than the muscle.
Word origin
Where “endometrium” comes from
Formed from endo-, from Greek endon, meaning "within," and metrium, from Greek metra, meaning "uterus."