Rectus sheath

Dr Henry Knipe et al.

The rectus sheath encloses the rectus abdominis and pyramidalis muscles and forms an important component of the anterior abdominal wall.

Gross anatomy

The rectus sheath is composed of the aponeuroses of transversus abdominis, external oblique and internal oblique muscles, which form an anterior and posterior sheath that fuse laterally at the linea semilunaris and in the midline at linea alba

Only the middle segment of the rectus abdominis is completely enclosed, with the posterior sheath lacking in parts of the superior and inferior segments:

  • superior to the costal margin the aponeuroses are deficient because they either do not extend that far superiorly (internal and external oblique muscles) or attach to the costal margin (transversus abdominis)
  • inferior to the arcuate line, the internal oblique aponeurosis passes anterior to the rectus abdominis and since the other two aponeurosis are fused to it, the posterior surface of rectus abdominis is in contact with the transversalis fascia

Related pathology

Abdominal and pelvic anatomy
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Article information

rID: 24537
Section: Anatomy
Synonyms or Alternate Spellings:

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