The arcuate line of rectus sheath, the , the arcuate line, or the semicircular line of Douglas, is a horizontal line that demarcates the lower limit of the posterior layer of the

rectus sheath The rectus sheath, also called the rectus fascia,. is formed by the aponeuroses of the transverse abdominal and the internal and external oblique muscles. It contains the rectus abdominis and pyramidalis muscles. Structure The rectus sheath ca ...

. It is commonly known simply as the arcuate line. It is also where the

inferior epigastric artery In human anatomy, inferior epigastric artery refers to the artery that arises from the external iliac artery. It anastomoses with the superior epigastric artery. Along its course, it is accompanied by a similarly named vein, the inferior epig ...

and

vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

perforate the

rectus abdominis The rectus abdominis muscle, ( la, straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a paired straight muscle. It is a paired muscle, separated by a midline band of connective tissue called the linea alba. It exte ...

Structure

Superior to the arcuate line, the

internal oblique muscle The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fibe ...

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

splits to envelop the

rectus abdominis muscle The rectus abdominis muscle, ( la, straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a paired straight muscle. It is a paired muscle, separated by a midline band of connective tissue called the linea alba. It ex ...

both anteriorly and posteriorly. The anterior layer is derived from the

external oblique The abdominal external oblique muscle (also external oblique muscle, or exterior oblique) is the largest and outermost of the three flat abdominal muscles of the lateral anterior abdomen. Structure The external oblique is situated on the lateral ...

and the anterior lamina of the

internal oblique The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fibers ...

aponeurosis. The posterior layer is made up of the posterior lamina of the internal oblique aponeurosis and the transversus abdominis aponeurosis. Inferior to the arcuate line, the aponeuroses of the

external oblique muscle The abdominal external oblique muscle (also external oblique muscle, or exterior oblique) is the largest and outermost of the three flat abdominal muscles of the lateral anterior abdomen. Structure The external oblique is situated on the lateral ...

, the

, and the

transversus abdominis 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 which is deep to (layered below) t ...

merge and pass superficial to the

. Therefore, inferior to the arcuate line, the rectus abdominis rests directly on the

transversalis fascia The transversalis fascia (or transverse fascia) is a thin aponeurotic membrane of the abdomen. It lies between the inner surface of the transverse abdominal muscle and the parietal peritoneum. It forms part of the general layer of fascia lining ...

. The arcuate line occurs about half of the distance from the umbilicus to the

pubic crest Medial to the pubic tubercle is the pubic crest, which extends from this process to the medial end of the pubic bone. It gives attachment to the conjoint tendon, the rectus abdominis, the abdominal external oblique muscle, and the pyramidalis m ...

, but this varies from person to person. If one dissects the anterolateral

abdominal wall In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls. There is a common set of layers covering and forming all the walls: the deepest being the v ...

, the arcuate line may be difficult to see, since all the aponeuroses are

translucent In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions a ...

Clinical significance

Spigelian hernias and, exceedingly rarely, arcuate line hernias may occur inferior to the arcuate line. The arcuate line must be incised at its lateral-most point in order to enter the

space of Retzius Retropubic space is a potential avascular space located between the pubic symphysis and the urinary bladder. The retropubic space is a preperitoneal space, located behind the transversalis fascia and in front of peritoneum . Other names for the ...

and space of Bogros from within the rectus sheath during surgery during retrorectus repair and transversus abdominis release.

History

The arcuate line is also known as the linea semicircularis, and the semicircular line of Douglas.

References

External links

* - "Anterior Abdominal Wall: The Posterior Wall of the Rectus Sheath" * * * * * - "Anterior Abdominal Wall, Lower Part, Posterior View" {{Authority control Abdomen