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Abdominal Rectus Muscle

Abdominal Rectus Muscle is a long, broad, strap-like muscle, it is the principal vertical muscle of the anterior abdominal wall. It is also known as “abs” muscle.

The paired rectus muscles, separated by the linea alba, lie close together inferiorly. The rectus abdominis is three times as wide superiorly as inferiorly; it is broad and thin superiorly and narrow and thick inferiorly. Most of the rectus abdominis is enclosed in the rectus sheath. The rectus muscle is anchored transversely by attachment to the anterior layer of the rectus sheath at three or more tendinous intersections (transverse fibrous bands).

When tensed in muscular people, the areas of muscle between the tendinous intersections bulge outward. The intersections, indicated by grooves in the skin between the muscular bulges, usually occur at the level of the xiphoid process, at the umbilicus, and halfway between these structures.

See Also: Rectus Sheath Anatomy
rectus abdominis

Abdominal Rectus Muscle Anatomy

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

See Also: Quadratus Lumborum Muscle

Origin

The abdominal rectus muscle originates from:

  • Pubic symphysis,
  • Pubic crest

Insertion

The Abdominal Rectus Muscle inserts on:

  • Xiphoid process,
  • Costal cartilages of ribs 5-7

Innervation

The muscles are innervated by:

  • Intercostal nerves (T7-T11),
  • Subcostal nerve (T12)

Blood supply

The rectus abdominis has many sources of arterial blood supply:

  1. 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.
  2. The superior epigastric artery, a terminal branch of the internal thoracic artery, supplies blood to the upper portion.
  3. Numerous small segmental contributions come from the lower six intercostal arteries as well.

Action

The rectus abdominis is an important postural muscle. It is responsible for:

  • Trunk flexion,
  • Compresses abdominal viscera,
  • Expiration: it assists with breathing and plays an important role in respiration when forcefully exhaling.
Abdominal Rectus
OriginPubic symphysis,
Pubic crest
InsertionXiphoid process,
Costal cartilages of ribs 5-7
InnervationIntercostal nerves (T7-T11),
Subcostal nerve (T12)
Blood SupplyInferior epigastric and superior epigastric arteries;
contributions from posterior intercostal, subcostal and deep circumflex arteries
ActionTrunk flexion,
Compresses abdominal viscera,
Expiration

References & More

  1. Clinically Oriented Anatomy – 8th Edition
  2. Gray’s Anatomy for students, 2nd edition
  3. Abdomen, in Moore, K.L., Dalley, A.F., Agur, A.M.R. (eds). 2014. Clinically Oriented Anatomy: Seventh Edition. Lippincott Williams & Wilkins. Philadelphia. PA.
  4. Sevensma KE, Leavitt L, Pihl KD. Anatomy, Abdomen and Pelvis, Rectus Sheath. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537153/
  5. Jessen ML, Öberg S, Rosenberg J. Treatment Options for Abdominal Rectus Diastasis. Front Surg. 2019 Nov 19;6:65. doi: 10.3389/fsurg.2019.00065. PMID: 31803753; PMCID: PMC6877697. Pubmed
Last Reviewed
December 29, 2023
Contributed by
OrthoFixar

Orthofixar does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice.

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