#MuscleMonday!

This is the Abdominal External Oblique Muscle!

AKA External Oblique Muscle (of abdomen)

The external oblique is situated on the lateral (outer) and anterior (front) parts of the abdomen.

Origin:

  • the external surfaces and inferior borders of the fifth to twelfth ribs (lower eight ribs)

Insertion:

  • lowest ribs pass nearly vertically downward, and are inserted into the anterior half of the outer lip of the iliac crest
  • the middle and upper fibers, directed downward and forward, become aponeurotic (fibrous tissue similar to a tendon, but broader) at approximately the mid-clavicular line (a theoretical line running vertically down the surface of the body passing through the midpoint of the clavicle) and forms the anterior layer of the rectus sheath.

Actions:

  • Pull the chest downwards and compress the abdominal cavity
  • Ipsilateral (same side) side-bending
  • Contralateral (opposite side) rotation.
  • So the right external oblique would side bend to the right and rotate to the left.

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