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What is the action of the inferior oblique muscle?
Its actions are extorsion, elevation and abduction of the eye. Primary action is extorsion (external rotation); secondary action is elevation; tertiary action is abduction (i.e. it extorts the eye and moves it upward and outwards). The field of maximal inferior oblique elevation is in the adducted position.
What is the function of the superior and inferior oblique?
The primary (main) action of the superior oblique muscle is intorsion (internal rotation), the secondary action is depression (primarily in the adducted position) and the tertiary action is abduction (lateral rotation). The extraocular muscles rotate the eyeball around vertical, horizontal and antero-posterior axes.
What happens when the inferior oblique contracts?
The inferior oblique muscle originates from the floor of the orbit and inserts into the inferolateral surface of the eye. When it contracts, it laterally rotates the eye, in opposition to the superior oblique. The lateral rectus, which causes abduction of the eye, is innervated by the abducens nerve.
What does the superior oblique do?
These muscles are unique in that they do not originate from the common tendinous ring, have an angular attachment to the eyeball, and they attach to the posterior aspect of the eyeball. The superior oblique functions explicitly to move the eye in the down-and-out position and intort the eye.
What eye movement is caused by the inferior oblique?
[2] The inferior oblique is responsible for extorsion, elevation, and abduction. Because of their course, the superior and inferior oblique muscles are the only muscles that can depress or elevate the eye, respectively when the eye moves in adduction.
Which direction does the eye turn if you move the inferior oblique extraocular muscle?
inferior oblique produces To direct the eye upward or downward, two muscles contract synergistically as the two antagonist muscles relax. For example, to elevate the eye while looking straight ahead, the superior rectus and inferior oblique contract together as the inferior rectus and superior oblique relax.
How do you test for inferior obliques?
To test superior rectus from the inferior oblique, the clinician asks the patient to first look out (or lateral) to orient the visual gaze axis perpendicular to the inferior oblique muscle fiber direction, then up. After the inferior oblique is trapped, the only muscle that can mediate elevation is the superior rectus.
What causes superior oblique palsy?
A common cause of acquired superior oblique palsy is head trauma, including relatively minor trauma. A concussion or whiplash injury from a motor vehicle accident may be sufficient enough to cause the problem. Rare causes of superior oblique palsy are stroke, tumor and aneurysm.
What is the function of the inferior oblique muscle?
Two of those muscles, the superior and inferior rectus, move the eye up and down when the eye is rotated away from the nose. When the eye is turned toward the nose, the inferior oblique muscle is responsible for elevating the eye, turning the top of it away from the nose, and moving it outward.
Where is the inferior oblique located in the eye?
Inferior oblique is a thin, narrow muscle of the eye. It is one of the 6 extraocular muscles , also referred to as the extrinsic muscles of the orbit . Like the other eye muscles, inferior oblique is named by its position within the orbit, relative to the eyeball.
What is the fascial sheath of the inferior oblique?
The fascial sheath of inferior oblique blends with the thickened sheath of the inferior rectus muscle. These two then blend with the medial and lateral check ligaments, which are triangular sheet expansions of the medial and lateral recti muscles.
Where is the abdominal oblique located in the body?
External abdominal oblique is a paired muscle located on the lateral sides of the abdominal wall. Along with internal abdominal oblique and transversus abdominis, it comprises the lateral abdominal muscles.