In which region of the spine is the thoracolumbar fascia thickest?

It is thickest and strongest in the lumbar region, whereas it thins out in the upper thoracic regions.

Between which muscle layers is the nuchal fascia located?

The nuchal fascia (fascia nuchae) lies in the posterior neck region strictly between the superficial and deep muscle layers.

Which muscle originates from the fusion site of the thoracolumbar fascia layers?

The aponeurosis of the transversus abdominis muscle (m. transversus abdominis) arises from the site where the superficial and deep layers fuse laterally.

To which structures does the deep layer of the thoracolumbar fascia attach?

It extends from the transverse processes of the lumbar vertebrae to the 12th rib and above, and laterally fuses with the quadratus lumborum and intertransverse muscles.

Home › Human Anatomy › Fasciae of the Back

Fasciae of the Back

Fasciae dorsi

For medical students2 min readUpdated 2026-10-10

Fasciae of the back are connective tissue structures covering the muscular masses of the posterior trunk and neck. They isolate muscle layers, form fibrous sheaths for them, and serve as an origin point for several abdominal muscles.

Superficial fasciaA thin subcutaneous layer containing adipose tissue, blood vessels, and nerves.

Nuchal fasciaLocated between the neck muscle layers, attaching to the superior nuchal line.

Thoracolumbar fasciaA dense aponeurotic plate of two layers enclosing the deep back muscles.

Layer fusionAt the lateral border of the *m. erector spinae*, the layers fuse to give origin to abdominal aponeuroses.

Superficial Fascia of the Back

This is a thin subcutaneous layer continuous with the general superficial fascia of the entire trunk.

Its main function is to cover the superficial back muscles. Within this connective tissue layer lie subcutaneous adipose tissue, blood vessels, and nerve trunks that supply the skin of the posterior body wall.

Nuchal Fascia (Fascia Nuchae)

This fascia is localized exclusively in the posterior region of the neck. Topographically, it lies strictly between the superficial and deep muscle layers, separating them.

Attachments of the nuchal fascia:

Superiorly: attaches firmly to the superior nuchal line of the occipital bone.
Medially: blends strongly with the ligamentum nuchae running along the midline.
Laterally: transitions smoothly into the superficial layer of the cervical fascia, ensuring continuity of fascial compartments.

Thoracolumbar Fascia (Fascia Thoracolumbalis)

This is a massive and very dense fibrous plate that encloses the deep back muscles. It varies in thickness: it is thickest and strongest in the lumbar region, whereas it thins out considerably in the upper thoracic region.

Anatomically, it divides into two layers — the deep (anterior) and superficial (posterior) layers.

Deep (Anterior) Layer

Arises from the transverse processes of the lumbar vertebrae, ascends to the 12th rib, and continues upward.

In the lumbar region, this layer helps form an isolated fibrous compartment for the deep back muscles.
Laterally, it fuses firmly with the quadratus lumborum and intertransversarii muscles.

Superficial (Posterior) Layer

Encloses the muscles posteriorly and has extensive attachments:

Medially: attaches to the spinous processes of the thoracic and lumbar vertebrae, as well as the sacrum and iliac crest.
Laterally: extends to the angles of the ribs.

Clinical and Biomechanical Significance

The lateral border of the thoracolumbar fascia is of particular significance. In the lumbar region, at the lateral margin of the erector spinae muscle (m. erector spinae), the superficial and deep layers fuse.

This fusion creates a closed fibrous sheath for the erector spinae muscle. From this fascial junction, the aponeurosis of the transversus abdominis muscle (m. transversus abdominis) takes its origin anteriorly. Thus, the thoracolumbar fascia acts as a crucial connecting structure between the posterior abdominal wall and the lumbar region.

Frequently asked questions

In which region of the spine is the thoracolumbar fascia thickest?: It is thickest and strongest in the lumbar region, whereas it thins out in the upper thoracic regions.
Between which muscle layers is the nuchal fascia located?: The nuchal fascia (fascia nuchae) lies in the posterior neck region strictly between the superficial and deep muscle layers.
Which muscle originates from the fusion site of the thoracolumbar fascia layers?: The aponeurosis of the transversus abdominis muscle (m. transversus abdominis) arises from the site where the superficial and deep layers fuse laterally.
To which structures does the deep layer of the thoracolumbar fascia attach?: It extends from the transverse processes of the lumbar vertebrae to the 12th rib and above, and laterally fuses with the quadratus lumborum and intertransverse muscles.

Go deeper

Detailed anatomy of the superficial and deep layers of the thoracolumbar fascia
Connection of the thoracolumbar fascia with the transversus abdominis aponeurosis
Topography of the nuchal fascia and its transition into cervical fascia
Formation of the fibrous sheath of the m. erector spinae
Attachment sites of the superficial layer to the sacrum and iliac bone