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Transverse abdominal muscle
Last reviewed: 19.11.2021
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The transverse muscle of the abdomen (m. Transversus abdominis) forms the deepest, third layer in the lateral parts of the abdominal wall. The bunches of the transverse abdominal muscle are arranged horizontally, passing forward and medially. They originate on the inner surface of the six lower ribs (occupying the spaces between the teeth of the rib side of the diaphragm), on the deep plate of the lumbosacral fascia, the anterior half of the inner lip of the iliac crest and the lateral third of the inguinal ligament. Near the lateral margin of the rectus abdominis muscle bundles pass into the wide aponeurosis along a line concave in the medial direction - the semilunar (spiegel) line (hinea semilunaris).
The function of the transverse abdominal muscle: reduces the size of the abdominal cavity, being an important part of the abdominal press; pulls the ribs forward to the median line.
Innervation of the transverse abdominal muscle: intercostals (ThV-ThXII), ilio-hypogastric (ThXII-LI) and ilio-inguinal (LI) nerves.
Blood supply to the transverse abdominal muscle: posterior intercostal arteries, upper and lower epigastric arteries, muscular-diaphragmatic artery.