The paired muscle is separated at the midline by a band of dense connective tissue called the linea alba, and the connective tissue defining each lateral margin of the rectus abdominus is the linea semilunaris.

Each rectus abdominus is traversed by bands of connective tissue called the tendinous intersections, which interrupt it into distinct muscle bellies.

In people with low body fat, these muscle bellies can be viewed externally in sets from as few as two to as many as twelve, although six is the most common.

[3] The rectus abdominis is a very long flat muscle, which extends along the whole length of the front of the abdomen, and is separated from its fellow of the opposite side by the linea alba.

Classification of the vascular anatomy of muscles: First, the inferior epigastric artery and vein (or veins) run superiorly on the posterior surface of the rectus abdominis, enter the rectus fascia at the arcuate line, and serve the lower part of the muscle.

It also helps in keeping the internal organs intact and in creating intra-abdominal pressure, such as when exercising or lifting heavy weights, during forceful defecation or parturition (childbirth).

With an ageing population and the widespread use of anticoagulant medications, there is evidence that this historically benign condition is becoming more common and more serious.