Medial and Lateral Margins of the Uterus

Description

Along the uterine body, the margo lateralis (lateral margin) runs from the fundus superiorly toward the isthmus inferiorly, forming the lateral contour where the peritoneum reflects and the broad ligament attaches. Each margin is paired, right and left, and converges superiorly at the fundal contour while remaining separated by the uterine cavity within. Medially, the endometrial cavity lies deep to the myometrium, and the serosal perimetrium defines the external surface. At the level of the uterine horn (cornu uteri), the border blends with the tubal junction and the attachment region for the utero-ovarian ligament and round ligament. This border matters because it is the anatomic corridor for the uterine vessels as they approach the uterus within the base of the broad ligament, with the ureter passing inferior to the uterine artery near the cervix (water under the bridge). It is a surgical danger zone. Lateral extension of leiomyomas, adenomyosis-related uterine enlargement, and deep infiltrating endometriosis can distort the margo lateralis and displace adjacent pelvic structures, changing the relationship between uterine artery, ureter, and cervix during hysterectomy or uterine artery ligation. Use this view to teach uterine surface anatomy in gross anatomy, OB-GYN surgical anatomy, and pelvic dissection labs, or to support textbook figures on uterine support and ligamentous attachments (broad ligament, round ligament, ovarian ligament) and hysterectomy steps. It also fits patient-facing materials explaining where fibroids grow (subserosal vs intramural) and why lateral fibroids can complicate surgery. Anatomical accuracy verified by SciePro's Medical Advisory Board.