Internal Oblique

This section is about the
muscles of the human torso

The internal oblique muscles are deep muscles of the anterior and lateral parts of the abdomen. Due to their lateral location, they can also be included in some views and descriptions of the posterior muscles of the human torso.

The internal oblique muscles are situated deeper within the body than the more 'superficial' (i.e. closer to the surface of the body) than the external oblique muscles outside / over them. Another way to remember this is to use the internal part of the name internal oblique as a clue, 'internal' referring to 'further from the surface of the body'.

Origin, Insertion and Actions of the Internal Oblique muscles:

Points of Origin:	Iliac crest (of the iliac bone) Lateral two-thirds of the inguinal ligament Thoracolumbar fascia, which is a sheet of connective tissue.
Points of Insertion:	Lower 3 or 4 ribs Linea alba, a region of white fibrous connective tissue situated along the (vertical) midline of the abdomen. (This divides the left and right rectus abdominus muscles and forms part of the definition of a muscular 'six pack'.)
Action(s):	The internal oblique muscles have several actions. The specific movements created or supported by these muscles depends on whether just one, or both, of the internal oblique muscles is contracted. In general, they can: Rotate, flex (bend), and laterally flex ('side-bend') the trunk or 'torso' of the body. Specifically: Contraction of both external oblique muscles compresses the abdomen and flexes the vertebral column. Contraction of one external oblique muscle alone flexes the vertebral column laterally and rotates it. Support the viscera (i.e. the organs within the body cavities, and especially the organs of the abdominal cavities, such as the stomach and other digestive organs). Assist with exhalation.

The internal oblique muscles are labelled on diagrams of the human anterior muscles and the human posterior muscles.

More about Muscles:

The following are some popular pages in the section about the human muscular system:

The structure of muscle tissue
The structure of muscle cells
Labelled diagrams of the muscles in different parts of the body including anterior muscles, posterior muscles and facial muscles
Types of muscle contractions
Movements at joints

There are also more pages about the words used to describe muscles (terminology), the anatomy and physiology of muscles, muscular disorders and associated topics. See also books about sports medicine.

This may be useful study or revision material for students following courses in human anatomy, sports science, massage, physiotherapy or other subjects that require knowledge of the muscular structures of the human body.

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Internal Oblique

Origin, Insertion and Actions of the Internal Oblique muscles:

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