Thoracodorsal fascia

The thoracodorsal fascia is also known as the thoracolumbar fascia. This fascia is a deep investing membrane that surrounds the deep muscles of the back of the trunk.

The thoracodorsal fascia has three layers: anterior, middle, and posterior. The anterior layer is the thinnest and the posterior layer is the thickest. The anterior and middle layers surround the quadratus lumborum muscle. The erector spinae muscle is enclosed between the middle and posterior layers.