Rectus Abdominis

The rectus abdominis is a muscle of the anterior abdominal wall.

It is a long, paired vertical muscle found on either side of the midline of the anterior abdominal wall. It is split into two by the linea alba.

• Attachments: Originates from the crest of the pubis bone. It inserts onto the xiphoid process of the sternum and the costal cartilage of ribs 5-7.
• Actions: As well as assisting the flat muscles in compressing the abdominal viscera, the rectus abdominis also stabilises the pelvis during walking, and depresses the ribs.
• Innervation: Thoracoabdominal nerves (T7-T11).
• Blood supply: Inferior epigastric and superior epigastric arteries; contributions from posterior intercostal, subcostal and deep circumflex arteries.

By OpenStax [CC BY 4.0], via Wikimedia Commons

Fig 1
The muscles of the anterolateral abdominal wall. Note how the flat muscles form aponeuroses medially.