cervix /sur″viks/ pl. cervices cervixes, the part of the uterus that lies partly in the vagina and partly in the pelvic cavity, joining the body (corpus) of the uterus at a narrow junction termed the isthmus. The cervix in a healthy woman who has not had children is a cylinder 2 to 3 cm in length, while the corpus is 7 to 8 cm in length and 4 to 5 cm in width, roughly pear shaped. The outer part of the cervix (the exocervix) is composed of squamous cells, changing at the squamocolumnar junction into columnar glandular cells (the endocervix) leading into the corpus. During labor the cervix thins (effacement) and opens (dilates), allowing the fetus to be born. Also called neck of uterus. See also effacement, endocervix.
