The lumbar fascia is the lumbar portion of the thoracolumbar fascia. It consists of three fascial layers - posterior, middle, and anterior - that enclose two (anterior and posterior) muscular compartments. The anterior and middle layers occur only in the lumbar region, whereas the posterior layer (as part of the thoracolumbar fascia) 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 (between anterior and middle layers), and the erector spinae in the posterior compartment (between middle and posterior layers).[1]: 274 Psoas major lies anterior to the anterior layer. Various superficial muscles of the posterior thorax and abdomen arise from the posterior layer - namely the latissimus dorsi, and serratus posterior inferior.[citation needed]