The rectus sheath (also called the rectus fascia.) is a tough fibrous compartment formed by the

aponeuroses An aponeurosis (; : aponeuroses) is a flattened tendon by which muscle attaches to bone or fascia. Aponeuroses exhibit an ordered arrangement of collagen fibres, thus attaining high tensile strength in a particular direction while being vulnerable ...

of the

transverse abdominal muscle The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral (front and side) abdominal wall, deep to (layered below) the inter ...

, and the

internal Internal may refer to: *Internality as a concept in behavioural economics *Neijia, internal styles of Chinese martial arts *Neigong or "internal skills", a type of exercise in meditation associated with Daoism * ''Internal'' (album) by Safia, 2016 ...

and external oblique muscles. It contains the

rectus abdominis The rectus abdominis muscle, () also known as the "abdominal muscle" or simply better known as the "abs", is a pair of segmented skeletal muscle on the ventral aspect of a person, person's abdomen. The paired muscle is separated at the midline b ...

and pyramidalis muscles, as well as vessels and nerves.

Structure

The rectus sheath extends between the inferior costal margin and costal cartilages of ribs 5-7 superiorly, and the pubic crest inferiorly. Studies indicate that all three aponeuroses constituting the rectus sheath are in fact bilaminar.

Below the costal margin

Superficial/anterior to the anterior layer of the rectus sheath are the following two layers: # Camper's fascia (anterior part of superficial fascia) # Scarpa's fascia (posterior part of the superficial fascia) Deep/posterior posterior layer of the rectus sheath (where present) are the following three layers: # transversalis fascia # extraperitoneal fat #

parietal peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesothe ...

Above the costal margin

Since the tendons of the internal oblique and transversus abdominis only reach as high as the

costal margin The costal margin, also known as the costal arch, is the lower edge of the chest (thorax) formed by the bottom edge of the rib cage. Structure The costal margin is the medial margin formed by the cartilages of the seventh to tenth ribs. It att ...

, 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.

Clinical significance

The rectus sheath is a useful attachment for surgical meshes during

abdominal surgery The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen (laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, liver, e ...

. This has a higher risk of

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

than many other attachment sites.

Additional images

File:Gray396.png, The Cremaster File:Gray398.png, The interfoveolar ligament, seen from in front.

References

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" {{Authority control Abdomen Muscles of the torso