Rectus abdominal muscle
Musculus rectus abdominis
Definition
The rectus abdominis muscle is a paired, long, ribbon-like muscle, located on either side of the linea alba. It extends from the sternum and costal cartilages cranially to the pubis caudally. It is divided by irregular and transverse tendinous intersections, the number of which varies according to the species. Forming part of the ventral abdominal wall, it is contained within the rectus sheath formed by the aponeuroses of the other abdominal muscles.
Origin: From the sternum and costal cartilage.
Insertion: On the prepubic tendon and the pecten of the pubic bone.
Reports: Enclosed in a fibrous sheath formed by the aponeuroses of the internal oblique and transverse muscles of the abdomen.
Action: Along with other abdominal muscles, compression of the abdominal viscera. This action, known as abdominal press, aids in such vital functions as expiration, urination, defecation, and parturition. Flexion of the vertebral column when fellow muscles contract. Lateral bending of the vertebral column.
Nerve: Medial branches of the intercostales and medial branches of the costoabdominalis, iliohypogstricus and ilioinguinalis.
Blood Supply: cranial and caudal epigastric arteries:
Variations: | Origin | conformation | Number of tendinous intersections |
Canines/Felines | Up to the first costal cartilage. | Without widening in its middle. | 5 (+ or -1 ) |
Equines | Up to the fourth costal cartilage. | Its middle part is very wide and laterally convex. | 10 |
Ungulates | Up to the fourth or fifth costal cartilage. | Similar to equines. | 5 |
Suids | Its middle part is less wide than that of equines and thicker. | 8 to 10 | |
Leporids | Up to the first costal cartilage. | Narrow muscle. | 6 |
References
König HE, Liebich H-G. Veterinary Anatomy of Domestic Mammals: Textbook and Colour Atlas. 6th ed. Stuttgart: Schattauer; 2020.
Dyce KM, Sack WO, Wensing CJG. Textbook of Veterinary Anatomy. 5th ed. Saunders; 2017.
Evans HE, de Lahunta A. Miller’s Anatomy of the Dog. 5th ed. Elsevier; 2020.
Barone R. Anatomie comparée des mammifères domestiques, Tome 2, Arthrologie et myologie, 4th edition, Vigot, Paris, 2017.
