lumbosacral joint lumbosacral joint the lumbosacral joint is a joint of the body, between the last lumbar vertebra and the first sacral segment of the vertebral column. in some ways, calling it a "joint" (singular) is a misnomer, since the lumbosacral junction includes a disc between the lower lumbar vertebral body and the uppermost sacral vertebral body, as well as two lumbosacral facet joints (right and left zygapophysial joints). lumbosacral jointdetailsidentifierslatinarticulatio lumbosacralista98a03.2.07.001ta21687fma16209anatomical terminology