# Rectus sheath

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The **rectus sheath** (also called the **rectus fascia[1]**) is a tough fibrous compartment formed by the [aponeuroses](/source/Aponeuroses) of the [transverse abdominal muscle](/source/Transverse_abdominal), and the [internal](/source/Internal_oblique) and [external oblique muscles](/source/External_oblique_muscle). It contains the [rectus abdominis](/source/Rectus_abdominis_muscle) and [pyramidalis](/source/Pyramidalis_muscle) muscles, as well as vessels and nerves.[2]

## Structure

The rectus sheath extends between the inferior costal margin and costal cartilages of ribs 5-7 superiorly, and the pubic crest inferiorly.[2]

Studies indicate that all three aponeuroses constituting the rectus sheath are in fact bilaminar.**[3]**

### Below the costal margin

Region Illustration Description Above the arcuate line At the lateral border of the rectus abdominis muscle, the aponeurosis of the internal oblique muscle splits into an anterior layer and a posterior layer (this splitting forms a shallow groove - the semilunar line).[3] An anterior rectus sheath composed of the aponeurosis of the external oblique muscle and anterior portion of the aponeurosis of the internal oblique muscle passes in front of the rectus abdominis muscle.[2][3] A posterior rectus sheath composed of the posterior portion of the aponeurosis of the internal oblique muscle and the aponeurosis of the transversus abdominis passes behind the rectus abdominis muscle.[2][3] All aponeuroses of the rectus sheath unite at (and decussate across) the midline, forming the linea alba.[3] Below the arcuate line Below this level, the aponeuroses of all three muscles (including the transversus) pass in front of the rectus.[2][3] The posterior layer of the rectus sheath is thus absent and the rectus abdominis muscle is separated from the peritoneum only by the transversalis fascia.[2] Due to this reason, this region is more susceptible to herniation.[citation needed]

Superficial/anterior to the anterior layer of the rectus sheath are the following two layers:[4]

1. [Camper's fascia](/source/Camper's_fascia) (anterior part of superficial fascia)
1. [Scarpa's fascia](/source/Scarpa's_fascia) (posterior part of the superficial fascia)

Deep/posterior posterior layer of the rectus sheath (where present) are the following three layers:[citation needed]

1. [transversalis fascia](/source/Transversalis_fascia)[4]
1. [extraperitoneal fat](/source/Extraperitoneal_fat)[5]
1. [parietal peritoneum](/source/Parietal_peritoneum)[4]

### Above the costal margin

Since the tendons of the internal oblique and transversus abdominis only reach as high as the [costal margin](/source/Costal_margin), it follows that above this level the sheath of the rectus is deficient behind, the muscle resting directly on the cartilages of the ribs, and being covered only by the tendons of the external obliques.[citation needed]

## Clinical significance

The rectus sheath is a useful attachment for [surgical meshes](/source/Mesh) during [abdominal surgery](/source/Abdominal_surgery).[6] This has a higher risk of [infection](/source/Infection) than many other attachment sites.[6]

## References

1. Te Linde, Richard W. (1977), ["Te Linde's Operative Gynecology"](http://dl.minitoons.ir/iums/TeLinde's_Operative_Gynecology_10%20E.pdf), 10th ed., Rock, John A. & Jones Howard W. (eds.), Philadelphia, PA: Lippincott, p. 107, retrieved 2018-10-01.

1. Sevensma, Karlin E.; Leavitt, Logan; Pihl, Kerent D. (2023), ["Anatomy, Abdomen and Pelvis, Rectus Sheath"](https://www.ncbi.nlm.nih.gov/books/NBK537153/), *StatPearls*, Treasure Island (FL): StatPearls Publishing, [PMID 30725838](https://pubmed.ncbi.nlm.nih.gov/30725838), retrieved 2023-05-16

1. Sinnatamby, Chummy (2011). *Last's Anatomy*. 12th ed. p. 224. ISBN 978-0-7295-3752-0.

1. Flynn, William & Vickerton, Paula (2023), ["Anatomy, Abdomen and Pelvis: Abdominal Wall"](https://www.ncbi.nlm.nih.gov/books/NBK551649/), *StatPearls*, Treasure Island (FL): StatPearls Publishing, [PMID 31869113](https://pubmed.ncbi.nlm.nih.gov/31869113), retrieved 2023-05-16

1. ["extraperitoneal fascia"](https://medical-dictionary.thefreedictionary.com/extraperitoneal+fascia). *TheFreeDictionary.com*. Retrieved 2023-05-16.

1. Hollinsky, C. (2011-01-01), ["6.638 - Biomaterials for Hernia Repair"](http://www.sciencedirect.com/science/article/pii/B9780080552941002476), *Comprehensive Biomaterials*, Ducheyne, Paul (ed.), Oxford: Elsevier, pp. 593–604, ISBN 978-0-08-055294-1, retrieved 2021-01-21

## External links

- - "Incisions and the contents of the rectus sheath."
- - "Anterior Abdominal Wall: The Rectus Abdominis Muscle"
- - anterior layer
- - posterior layer above arcuate line
- - posterior layer above arcuate line
- - "The Rectus Sheath, Anterior View & Transverse Section"

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Adapted from the Wikipedia article [Rectus sheath](https://en.wikipedia.org/wiki/Rectus_sheath) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Rectus_sheath?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.