The arcuate line of rectus sheath (the arcuate line or the semicircular line of Douglas) is a line of demarcation[1] corresponding to the free inferior margin of the posterior layer of the rectus sheath[2] inferior to which only the anterior layer of the rectus sheath is present[3] and the rectus abdominis muscle is therefore in direct contact with the transversalis fascia.[1] The arcuate line is concave inferior-wards.[2]
The arcuate line is visible upon the inner surface of the abdominal wall.[1] The arcuate line may be a well-defined,[1][2] or may be represented by a gradual waning of the aponeurotic fibres with concomitant increasing prominence of the transversalis fascia.[2] The arcuate line occurs about midway between the umbilicus and pubic symphysis,[3] however, this varies from person to person.[citation needed]
The arcuate line must be incised at its lateral-most point in order to enter the space of Retzius and space of Bogros from within the rectus sheath during surgery during retrorectus repair and transversus abdominis release.[citation needed]
History
The arcuate line is also known as the linea semicircularis, and the semicircular line of Douglas.[5]