Abdominal internal oblique muscle


Abdominal internal oblique muscle
Abdominal internal oblique muscle
Illu trunk muscles.jpg
Muscles of the trunk.
Gray395.png
The Obliquus internus abdominis.
Latin Obliquus internus abdominis
Gray's subject #118 412
Origin Inguinal ligament, Iliac crest and the Lumbodorsal fascia.
Insertion    Linea alba, Xiphoid process and the inferior ribs.
Artery subcostal arteries.
Nerve peripheral n. VPR; Segmental N. T6-12, L1
Actions Compresses abdomen; unilateral contraction rotates vertebral column to same side.

The internal oblique muscle (of the abdomen) is the intermediate muscle of the abdomen, lying just underneath the external oblique and just above (superficial to) the transverse abdominal muscle.

Contents

Structure

Its fibers run perpendicular to the external oblique muscle, beginning in the thoracolumbar fascia of the lower back, the anterior 2/3 of the iliac crest (upper part of hip bone) and the lateral half of the inguinal ligament. The muscle fibers run from these point superiomedially (up and towards midline) to the muscle's insertions on the inferior borders of the 10th through 12th ribs and the linea alba (abdominal midline seam).

In males, the cremaster muscle is also attached to the internal oblique.

Innervation

The internal oblique is innervated by the lower intercostal nerves, as well as the iliohypogastric nerve and the ilioinguinal nerve.

Actions

The internal oblique performs two major functions. First, it acts as an antagonist (opponent) to the diaphragm, helping to reduce the volume of the thoracic (chest) cavity during exhalation. When the diaphragm contracts, it pulls the lower wall of the chest cavity down, increasing the volume of the lungs which then fill with air. Conversely, when the internal obliques contract they compress the organs of the abdomen, pushing them up into the diaphragm which intrudes back into the chest cavity reducing the volume of the air filled lungs, producing an exhalation.

Secondly, its contraction rotates and side-bends the trunk by pulling the rib cage and midline towards the hip and lower back, of the same side. It acts with the external oblique muscle of the opposite side to achieve this torsional movement of the trunk. For example, the right internal oblique and the left external oblique contract as the torso flexes and rotates to bring the left shoulder towards the right hip. For this reason, the internal obliques are referred to as "same side rotators."

See also

References

  • Moore, Keith L; & Dalley Arthur R (2006). Clinically Oriented Anatomy (5th ed.). Lippincott Williams and Wilkins. ISBN 0-7817-3639-0.
  • [1]

Additional images

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Abdominal external oblique muscle — Muscles of the trunk …   Wikipedia

  • internal oblique — noun : a sheet of diagonally arranged abdominal muscle lying between the external oblique and transverse layers on either side of the trunk …   Useful english dictionary

  • Superior oblique muscle — Superior oblique Rectus muscles: 2 = superior, 3 = inferior, 4 = medial, 5 = lateral Oblique muscles: 6 = superior, 8 = inferior Other muscle: 9 = levator palpebrae superioris …   Wikipedia

  • Oblique — may refer to: Oblique angle, in geometry, an angle that is not a multiple of 90 degrees Oblique angle, synonym for Dutch angle, a cinematographic technique Oblique (album), by jazz vibraphonist Bobby Hutcherson Oblique banded rattail, a fish also …   Wikipedia

  • Muscle — is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart… …   Medical dictionary

  • Abdominal wall — Body cavities Diagram of sheath …   Wikipedia

  • Muscle — For other uses of Muscle , see Muscle (disambiguation). A top down view of skeletal muscle Muscle (from Latin …   Wikipedia

  • Abdominal obesity — Central obesity Classification and external resources A morbidly obese male. Weight 146 kg/322 lbs, height 177 cm/5 ft 10 in. The body mass index is 46. ICD 10 E66 …   Wikipedia

  • muscle — muscleless, adj. muscly, adj. /mus euhl/, n., v., muscled, muscling, adj. n. 1. a tissue composed of cells or fibers, the contraction of which produces movement in the body. 2. an organ, composed of muscle tissue, that contracts to produce a… …   Universalium

  • abdominal muscle — Any of the muscles of the front and side walls of the abdominal cavity. Three flat layers the external oblique, internal oblique, and transverse abdominis muscles extend from each side of the spine between the lower ribs and the hipbone. The… …   Universalium


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.