Lumbar fascia

See also: Thoracolumbar fascia

The lumbar fascia is the lumbar portion of the thoracolumbar fascia. It consists of three fascial layers - posterior, middle, and anterior - that enclose two (anterior and posterior) muscular compartments. The anterior and middle layers occur only in the lumbar region, whereas the posterior layer (as part of the thoracolumbar fascia) extends superiorly to the inferior part of the neck, and the inferiorly to the dorsal surface of the sacrum. The quadratus lumborum is contained in the anterior muscular compartment (between anterior and middle layers), and the erector spinae in the posterior compartment (between middle and posterior layers).[1]: 274  Psoas major lies anterior to the anterior layer. Various superficial muscles of the posterior thorax and abdomen arise from the posterior layer - namely the latissimus dorsi, and serratus posterior inferior.[citation needed]

## Anatomy

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The posterior layer and middle layer unite at the lateral margin of erector spinae, forming a though raphe; all three layers then unite at the lateral margin of quadratus lumborum, thus forming the aponeurotic origin of the transversus abdominis muscle.[2]: 814–815

### Layers

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#### Posterior layer

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The posterior layer is thick, being reinforced by the aponeurosis (origin) of the latissimus dorsi muscle.[1]: 274  It consists of a superficial lamina derived primarily from the latissimus dorsi and serratus posterior inferior, and a deeper lamina which forms a retinacular sheet encapsulating the paraspinal muscles.[3] The posterior layer is attached to the spinous processes of lumbar and sacral vertebrae, and to the supraspinous ligament.[2]: 814–815

At sacral levels, the posterior layer attaches to the posterior superior iliac spines, and posterior iliac crest, fuses with the underlying erector spinae muscle aponeurosis,[2]: 814–815  and extends along the transverse tubercles of the sacrum.[1]: 274

In the thoracic region, the posterior layer (i.e. thoracic part of thoracolumbar fascia) attaches to the supraspinous ligament and spinous processes of all thoracic vertebrae, and to the costal angles of all ribs. It extends as far superiorly as the inferior part of the neck.[1]: 274

#### Middle layer

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The middle layer is attached superiorly to the inferior margin of the 12th rib, and the lumbocostal ligament, medially to the tips of transverse processes of lumbar vertebrae, and inferiorly to[2]: 814–815  the posterior part of the intermediate area of[4] the iliac crest.[2]: 814–815

#### Anterior layer

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The anterior layer is the thinnest of the three layers.[citation needed] The anterior layer forms the lateral arcuate ligament superiorly, is attached medially to anterior surfaces of transverse processes of lumbar vertebra, and is attached inferiorly to the iliolumbar ligament and adjoining iliac crest.[2]: 814–815

### Relations

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The ascending colon[1]: 257  and descending colon[1]: 258  lie upon the lumbar fascia.

The lumbar fascia gives origin to the latissimus dorsi muscle (which arises from posterior layer of lumbar fascia),[1]: 40  abdominal internal oblique muscle (which arises along the entire length of the lumbar fascia), transversus abdominis muscle,[1]: 222  and gluteus maximus muscle.[1]: 125

The psoas fascia (a part of the iliac fascia) laterally blends with the lumbar fascia.[1]: 272  The lateral arcuate ligament arises as a thickening of the lumbar fascia.[1]: 185  The superior band of the iliolumbar ligament is continuous with the anterior layer of lumbar fascia.[1]: 325  The inferior portion of the supraspinous ligament becomes indistinct amid the lumbar fascia.[1]: 424

Each subcostal artery passes across the anterior surface of the lumbar fascia before reaching the anterior abdominal wall.[1]: 276  Each subcostal nerve passes across the anterior aspect of the anterior layer of lumbar fascia.[1]: 278  The ilioinguinal nerve pierces the anterior layer of lumbar fascia posterior to the kidney to come to pass inferoanteriorly anterior to the anterior layer of lumbar fascia.[1]: 279

## Function

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The lumbar fascia binds the deep muscles of the back to the spine and to the transverse processes of the vertebrae. Additionally the lumbar fascia is an attachment for the gluteus maximus muscle and the latissimus dorsi muscle.[citation needed]

## References

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1. ^ a b c d e f g h i j k l m n o p Sinnatamby C (2011). Last's Anatomy (12th ed.). Elsevier Australia. ISBN 978-0-7295-3752-0.
2. ^ a b c d e f Standring S (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42nd ed.). New York. ISBN 978-0-7020-7707-4. OCLC 1201341621.`{{cite book}}`: CS1 maint: location missing publisher (link)
3. ^ Willard FH, Vleeming A, Schuenke MD, Danneels L, Schleip R (December 2012). "The thoracolumbar fascia: anatomy, function and clinical considerations". Journal of Anatomy. 221 (6): 507–536\. doi:10.1111/j.1469-7580.2012.01511.x. PMC 3512278. PMID 22630613.
4. ^ Vleeming A, Pool-Goudzwaard AL, Stoeckart R, van Wingerden JP, Snijders CJ (April 1995). "The posterior layer of the thoracolumbar fascia. Its function in load transfer from spine to legs". Spine. 20 (7): 753–758\. doi:10.1097/00007632-199504000-00001. PMID 7701385. S2CID 46591986.