The internal iliac lymph nodes (or hypogastric) surround the internal iliac artery and its branches (the hypogastric vessels), and receive the lymphatics corresponding to the distribution of the branches of it, i. e., they receive lymphatics from all the pelvic viscera, from the deeper parts of the perineum, including the membranous and cavernous portions of the urethra, and from the buttock and back of the thigh. The internal iliac lymph nodes also drain the superior half of the rectum, above the pectinate line.Regional lymph tissueDeep lymph nodes and vessels of the thorax and abdomen. The internal iliac lymph nodes (or hypogastric) surround the internal iliac artery and its branches (the hypogastric vessels), and receive the lymphatics corresponding to the distribution of the branches of it, i. e., they receive lymphatics from all the pelvic viscera, from the deeper parts of the perineum, including the membranous and cavernous portions of the urethra, and from the buttock and back of the thigh. The internal iliac lymph nodes also drain the superior half of the rectum, above the pectinate line. It does not receive lymph from the ovary or testis, which drain to the paraaortic lymph nodes. This article incorporates text in the public domain from page 704 of the 20th edition of Gray's Anatomy (1918)