Lateral ligament: its anatomy and clinical importance.

Since Miles proposed abdominoperineal excision as a radical surgery for rectal cancer in 1908, surgeons have recognized the lateral ligament in the pararectal space of their patients and attached clinical importance to it, although anatomists did not describe any such configuration in cadavers. By analyzing an experience of 421 lower rectal cancer cases at the Cancer Institute Hospital in Tokyo, discussion of the lateral ligament was focused on its relationship to the fascial arrangements in the pelvis, the pelvic autonomic nervous system, and the lymphatic drainage of the rectum. The lateral ligament is not an anatomical term, but a clinical or surgical one. It exists in a living pelvis as a condensation of connective tissue around the middle rectal artery and is divided into two segments by the inferior hypogastric nerve plexus inside it and the visceral endopelvic fascia around it. The lateral ligament is a pathway of blood vessels and nerve fibers toward the rectum and lymphatic vessels from the lower rectum toward the iliac lymph nodes. Therefore, the lateral ligament plays a critical role in surgery for lower rectal cancer in two respects: the anatomic extent of resection for curing rectal cancer, and the preservation of sexual function.