The Thoracolumbar Fascia is the fascia of the erector spinae. Formed in the thoracic-lumbar region, it is a fascial covering comparable to the investing fascia of the limbs. The thoracolumbar fascia covers the erector spinae with its superficial layer and encloses anteriorly the lumbar part of the lateral tract of autochthonous back musculature with its deep layer. These two layers enclose the erector spinae in an osseofibrous canal. The canal is limited by the spinous processes and vertebral arches, the transverse and costal processes, the thoracic wall, and in the lumbar region by the deep layer of the thoracolumbar fascia.