lumbar fascia lumbar fascia the lumbar fascia is the lumbar portion of the thoracolumbar fascia. it consists of three fascial layers that enclose two (anterior and posterior) muscular compartments. the anterior and middle layers occur only in the lumbar region, whereas the posterior layer extends superiorly to the inferior part of the neck, and the inferiorly to the dorsal surface of the sacrum. the quadratus lumborum is contained in the anterior muscular compartment, and the erector spinae in the posterior compartment.: 274 anatomy relations the ascending colon: 257 and descending colon: 258 lie upon the lumbar fascia. the lumbar fascia gives origin to the latissimus dorsi muscle (which arises from posterior layer of lumbar fascia),: 40 abdominal internal oblique muscle (which arises along the entire length of the lumbar fascia), transversus abdominis muscle,: 222 and gluteus maximus muscle.: 125 the psoas fascia (a part of the iliac fascia) laterally blends with the lumbar fascia.: 272 the lateral arcuate ligament arises as a thickening of the lumbar fascia.: 185 the superior band of the iliolumbar ligament is continuous with the anterior layer of lumbar fascia.: 325 the inferior portion of the supraspinous ligament becomes indistinct amid the lumbar fascia.: 424 each subcostal artery passes across the anterior surface of the lumbar fascia before reaching the anterior abdominal wall.: 276 each subcostal nerve passes across the anterior aspect of the anterior layer of lumbar fascia.: 278 the ilioinguinal nerve pierces the anterior layer of lumbar fascia posterior to the kidney to come to pass inferoanteriorly anterior to the anterior layer of lumbar fascia.: 279 posterior layer medially, the posterior layer attaches to the tips of the lumbar and sacral spines and the interspinous ligaments. to the sides it blends with the middle layer at the lateral border of the erector spinae muscle group that extends the vertebral column (bending the spine so the head moves back relative to the chest), also known as sacrospinalis in older texts and more recently as extensor spinae, though this term is not in widespread use. superiorly it continues on to the back of the thorax where it attaches to the vertebral spines and the ribs, inferiorly to the posterior quarter of the outer lip of the iliac crest. middle layer left hip-joint, opened by removing the floor of the acetabulum from within the pelvis. (trans. ligament labeled at center.) medially, the middle layer attaches to the tips of the lumbar transverse processes and the transverse ligaments, laterally, it blends with the anterior layer at the lateral border of the quadratus lumborum, and superiorly it attaches to the lower border of the 12th rib and to the lumbocostal ligament and inferiorly, it attaches to the posterior part of the intermediate area of the iliac crest. anterior layer medially, the anterior layer attaches to the vertical ridges on the anterior surface of the lumbar transverse processes, laterally it blends with the middle layer at the lateral border of the quadratus lumborum and superiorly, it forms the lateral arcuate ligament, extending from the tip of the first lumbar transverse process to the 12th rib and inferiorly, it attaches to the inner lip of the iliac crest and iliolumbar ligament. function the lumbar fascia binds the deep muscles of the back to the spine and to the transverse processes of the vertebrae. additionally the lumbar fascia is an attachment for the gluteus maximus muscle and the latissimus dorsi muscle.