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Outer oblique abdominal muscle
Last reviewed: 23.04.2024
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The external oblique abdominal muscle (m. Obliquus extemus abdominis) is the most superficial and extensive of the abdominal muscles. It begins with large teeth on the outer surface of the eight lower ribs. The upper five muscle teeth enter between the teeth of the anterior dentate muscle, and the lower three - between the teeth of the latissimus muscle of the back. The upper tufts of the outer oblique abdominal muscle begin on the ribs near their cartilages and pass almost horizontally. Below located beams go obliquely from top to bottom and medially. The bunches of the lowest part of the muscle follow almost vertically downwards. Muscular fascicles of the outer oblique abdominal muscle, not reaching the edge of the rectus abdominis front and the iliac wing at the bottom, pass into a wide aponeurosis.
The lowest part of the aponeurosis of the external oblique abdominal muscle is directed to the outer lip of the iliac crest (laterally, posteriorly) and to the pubic tubercle (anteriorly, medially). The lower thickened edge of the aponeurosis of the external oblique abdominal muscle is stretched between the superior anterior iliac spine and pubic tubercle and forms the inguinal ligament (ligamentum inguinale). At the place of attachment to the pubic bone aponeurosis of the muscle is divided into two legs - the medial and lateral. The medial crus mediate is attached to the anterior surface of the pubic symphysis, and the lateral leg (crus laterale) is attached to the pubic tubercle.
Function: with a strengthened pelvic girdle and bilateral contraction, the external oblique abdominal muscle lowers the ribs, contributing to the exhalation act, and also bends the spine. With one-sided reduction, this muscle turns the trunk in the opposite direction. With free, deprived support of the lower limbs (in the supine position on the back), the muscles raise the pelvis. Muscles are part of the structures of the abdominal press.
Innervation: intercostal nerves (ThV-ThXII), ilio-hypogastric nerve (ThXII-LI) and ilio-inguinal nerve (LI).
Blood supply: posterior intercostal arteries, lateral thoracic artery, superficial artery surrounding iliac bone.
Above the iliac crest, between the posterior edge of the outer oblique muscle of the abdomen and the lower anterior margin of the latissimus muscle of the back, there remains a triangular form of a lumbar triangle (petites). The bottom (bottom side) of this triangle is formed by the iliac crest. The lumbar triangle can serve as a place for the formation of hernias.
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