A lymph node with a lymph center located within the caudal abdomen and pelvis, on the ventral side of the lumbar region. Includes the medial iliac, internal iliac (previously termed hypogastric) and sacral lymph nodes. [ NCIT:C77655 http://www.ncbi.nlm.nih.gov/pubmed/32655159 https://orcid.org/0000-0002-0819-0473 ]