Abdominal muscle

Abdominal muscle

The abdominal muscles, as illustrated in Gray's Anatomy.

The abdominal muscles are a group of muscles that comprise the anterior and lateral walls of the abdomen. They assist in the regular breathing movement and provide an increase of intra-abdominal pressure as in defecation, urination, and childbirth.

Structure

The abdominal muscles can be divided into four main groups:

• Rectus abdominis
• Transversus abdominis
• Internal oblique
• External oblique

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The muscles of the abdomen, lower back and pelvis.

Rectus abdominis

The rectus abdominis is a long muscle that extends along the front of the abdomen. It is the most superficial (closest to the skin) of the abdominal muscles.

Transversus abdominis

The transversus abdominis is the deepest (innermost) of the abdominal muscles. It wraps around the torso from front to back and from the ribs to the pelvis.

Internal oblique

The internal oblique is an abdominal muscle located just inside the hip bone. It is the intermediate layer of the abdominal muscles.

External oblique

The external oblique is the outermost of the three flat muscles of the lateral anterior abdomen.

Function

The abdominal muscles have different important functions. They assist in the breathing process by providing a powerful exhale when the diaphragm relaxes and they also provide postural support and protection to the inner organs in the abdominal and pelvic regions.

See also

• Human anatomy
• Muscular system
• Core (anatomy)