part of dorsum abdominal segment of trunk lower back loin lower back regio lumbalis dorsum of abdomen FMA:61681 MA:0000027 lumbar region Subdivision of abdominal segment of trunk which in humans is demarcated from the front of the abdomen by the posterior surface of the anterior layer of the thoracolumbar fascia and the anterior surface of the lumbar vertebral column; together with the front of the abdomen, it constitutes the abdomen[Modified from FMA]. lumbar region of back SCTID:182343007 BTO:0001505 abdominal back lumbar part of back EMAPA:36623 posterior part of abdomen NCIT:C34004 lumbos lombus back of abdomen overlaps with region sometimes called 'loin' subdivision of trunk