Overview
It is wrapped in the rectus sheath, formed by the aponeuroses of the oblique and transverse abdominal muscles. The two recti are separated by the linea alba. It is crossed by numerous transverse tendinous intersections. Caudally it ends in the prepubic tendon, which anchors it to the pubis together with the aponeuroses of the obliques.
Origin
Ventral surface of the sternum and costal cartilages.
Insertion
Pecten of the pubis, through the prepubic tendon.
Action
Compresses the abdomen and flexes the vertebral column.
Innervation
Ventral branches of the caudal thoracic and cranial lumbar nerves.
Clinical relevance
- Ventral midline laparotomy, with the horse in dorsal recumbency, is the standard approach for colic surgery: it passes through the linea alba between the two recti and allows much of the intestine to be exteriorised. Its best known complications are wound infection and incisional hernia.
- Prepubic tendon rupture occurs mainly in mares in late pregnancy, often of heavy breeds or with twins or hydrops of the fetal membranes: the abdomen drops, ventral oedema appears and the udder is displaced cranially.
- Umbilical hernia in foals occurs through the umbilical ring, in the linea alba.