What anatomical structure connects the sides of the uterus to the lateral walls of the pelvis?

The broad ligament serves as the anatomical structure that connects the sides of the uterus to the lateral walls of the pelvis. It is a wide fold of peritoneum that envelops the uterus and extends laterally to anchor it to the pelvic walls, providing structural support for the uterus while also containing important vascular, lymphatic, and nerve pathways.

The broad ligament also has subdivisions that include the mesometrium, which is the portion that supports the uterus, the mesosalpinx, which supports the fallopian tubes, and the mesovarium, which supports the ovaries. This comprehensive support system is crucial for maintaining the proper position of the reproductive organs within the pelvis.

In contrast, the uterine ligaments also play significant roles, but they are primarily involved in stabilizing the uterus rather than connecting it to the pelvic walls. The uterine sacral ligament helps support the uterus against posterior displacement, the cardinal ligament offers support by anchoring the cervix laterally, and the round ligament primarily provides support by keeping the uterus anteverted during pregnancy.