Anatomy, Abdomen and Pelvis, Rectus Sheath

The rectus sheath is the durable, resilient, fibrous compartment that contains both the rectus abdominis muscle and the pyramidalis muscle. The fascial coverings of the external oblique, internal oblique, and transversus abdominis muscles comprise the rectus sheath. The layers of decussating and interweaving fascial aponeuroses vary according to their position within the superior two-thirds of the sheath and the inferior third. Because of this variation and the clinical implications, it is crucial to understand the anterior and posterior laminae. The rectus sheath contains within it the superior and inferior epigastric arteries and veins, lymphatic vessels, and the thoracoabdominal nerves related to those particular structures.