Rectus Sheath Information
The Rectus sheath is formed by the aponeuroses of the Obliqui and Transversus. It contains the Rectus abdominis and Pyramidalis muscles.
It can be divided into anterior and posterior laminae.
The arrangement of the layers has important variations at different locations in the body.
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Below the costal margin
For context, above the sheath are the following two layers:
- Camper's fascia (anterior part of the Superficial fascia)
- Scarpa's fascia (posterior part of the Superficial fascia)
Within the sheath, the layers vary:
| Region | Illustration | Description |
| Above the arcuate line | At the lateral margin of the Rectus, the aponeurosis of the Obliquus internus divides into two lamellae:
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| Below the arcuate line | Below this level, the aponeuroses of all three muscles (including the internus) pass in front of the Rectus. |
Below the sheath are the following three layers:
The Rectus, in the situation where its sheath is deficient below, is separated from the peritoneum only by the transversalis fascia, in contrast to the upper layers, where part of the internal oblique also runs beneath the rectus. Because of the thinner layers below, this region is more susceptible to herniation.
Above the costal margin
Since the tendons of the Obliquus internus and Transversus only reach as high as the 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 merely by the tendon of the Obliquus externus.
Additional images
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The Cremaster
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The interfoveolar ligament, seen from in front.
References
External links
- SUNY Figs 35:04-02 - "Incisions and the contents of the rectus sheath."
- SUNY Labs 35:10-0103 - "Anterior Abdominal Wall: The Rectus Abdominis Muscle"
- SUNY Anatomy Image 7180 - anterior layer
- SUNY Anatomy Image 7133 - posterior layer above arcuate line
- SUNY Anatomy Image 7574 - posterior layer above arcuate line
- 174784590 at GPnotebook
- rectussheath at The Anatomy Lesson by Wesley Norman (Georgetown University)
- Atlas of anatomy at UMich abdo_wall60 - "The Rectus Sheath, Anterior View & Transverse Section"
- Anatomy at MUN digest/abwall
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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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Categories: Abdomen | Muscles of the torso |
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