Superficial fascia of the back
It is a thin subcutaneous layer that forms a direct continuation of the general superficial fascia of the entire trunk.
Its main function is to cover the superficial muscles of the back. Subcutaneous adipose tissue, blood vessels, and nerve trunks that supply and innervate the skin of the posterior body surface are located within the thickness of this connective tissue plate.
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.
The nuchal fascia is fixed in several directions:
- Superiorly: attaches tightly to a bony structure — the superior nuchal line of the occipital bone.
- Medially: fuses firmly with the ligamentum nuchae running along the midline.
- Laterally: transitions smoothly into the superficial layer of the cervical fascia, ensuring the continuity of fascial sheaths.
Thoracolumbar fascia (fascia thoracolumbalis)
This is a massive and very dense fibrous plate that encloses the deep back muscles. It has an uneven thickness: it is maximally developed and thickened in the lumbar region, whereas it becomes noticeably thinner in the upper thoracic regions.
Anatomically, it is divided into two layers — a deep (anterior) and a superficial (posterior) layer.
Deep (anterior) layer
Originates from the transverse processes of the lumbar vertebrae, ascends to the 12th rib, and continues further upward.
- In the lumbar region, this layer participates in the formation of an isolated fibrous sheath for the deep muscles.
- Laterally, it fuses tightly with the quadratus lumborum muscle and intertransverse muscles.
Superficial (posterior) layer
Encloses the muscles posteriorly and has extensive attachment lines:
- Medially: attaches to the spinous processes of the thoracic and lumbar vertebrae, as well as to the sacrum and iliac crest.
- Laterally: extends to the angles of the ribs, where it attaches.
Clinical and biomechanical significance
The lateral margin of the thoracolumbar fascia is of particular importance. In the lumbar region, at the lateral edge of the erector spinae muscle (m. erector spinae), the superficial layer fuses with the deep layer.
As a result of this fusion, a closed fibrous sheath is formed for this muscle. It is precisely from this fascial fusion site, extending anteriorly, that the aponeurosis of the transversus abdominis muscle (m. transversus abdominis) takes its origin. Thus, the thoracolumbar fascia acts as a crucial connecting structure of the posterior abdominal wall and the lumbar region.
Class and exam questions
In which spinal region 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 region of the neck, strictly between the superficial and deep muscle layers.
Which muscle originates from the fusion site of the thoracolumbar fascia layers?
From the site where the superficial layer fuses with the deep layer anteriorly, the aponeurosis of the transversus abdominis muscle (m. transversus abdominis) originates.
To which structures does the deep layer of the thoracolumbar fascia attach?
It runs from the transverse processes of the lumbar vertebrae to the 12th rib and above, and laterally fuses with the quadratus lumborum and intertransverse muscles.
What else to study on this topic
- Detailed anatomy of the superficial and deep layers of the thoracolumbar fascia
- Connection of the thoracolumbar fascia with the aponeurosis of the transversus abdominis muscle
- Topography of the nuchal fascia and its transition into the cervical fascia
- Formation of the fibrous sheath of m. erector spinae
- Attachment points of the superficial layer to the sacrum and ilium
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