QS Study

The thoracolumbar fascia is the fascia enclosing the deep muscles of the back. It is a very essential tissue of the body as it is needed for coordinated movement.

Layers – It is made up of three layers:

  1. Posterior
  2. Middle,
  3. Anterior.

The 3 layers fuse laterally to create a dense aponeurotic sheet which provides origin to the internal oblique and transversus abdominis muscles.

Extent

The posterior layer covers the loin and is continued upward on the back of the thorax and neck. The middle and anterior layers are confined to the lumbar region.

Fig: Thoracolumbar Fascia

Attachments

(A) Posterior layer: Medially, it is attached to the tips of the lumber and sacral spines and interspinous ligaments.

Laterally, in the blender with the middle layer at the lateral border of the creator spinae.

Superiorly, it is attached to the vertebral spines and the angles of the ribs.

Inferiorly, it is attached to the posterior one-fourth of the upper lip of the iliac crest.

(B) Middle layer:

Medially, it is attached to the tips of the lumbar transverse processes and intertransverse ligaments. Laterally, it blends with the anterior layer.

Superiorly, it is attached to the lower border of the 12th rib and to the lumbocostal ligament.

Inferiorly, it is attached to the posterior part of the intermediate area of the iliac crest.

(C) Anterior layer: Medially, it is attached to the vertical ridges on the anterior surface of the lumbar transverse processes.

Laterally, it blends with the middle layer. Superiorly, it forms the lateral arcuate ligament,

Inferiorly, it is attached to the inner lip of the iliac crest and the iliolumbar ligament.