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Introduction. Inferior oblique muscle overaction (IOOA) manifests by overelevation of the eye in adduction and is frequently associated with horizontal deviations. It is reported in 70% of patients with esotropia and 30% of patients with exotropia. There are two types of IOOA: primary and secondary.Introduction. Inferior oblique muscle overaction (IOOA) manifests by overelevation of the eye in adduction and is frequently associated with horizontal deviations. It is reported in 70% of patients with
Esotropia – Wikipedia
and 30% of patients with exotropia. There are two types of IOOA: primary and secondary.
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. All of the other muscles are innervated by the oculomotor nerve, as is the levator palpebrae superioris.
What movement does the inferior oblique do?
Function. 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 an inferior oblique myectomy?
Myectomy. Inferior oblique myectomy typically involves the surgical removal of a segment of muscle between the NFVB and the insertion of the muscle. 23,41. The muscle segment is cauterized prior to removal. The primary advantage is convenience as this procedure is faster than a recession.
What is superior oblique Overaction?
Definition. An ocular motility abnormality characterized by an overacting superior oblique muscle resulting to vertical incomitance of the eyes in lateral gaze.
How do I know if I have an inferior oblique muscle?
To test the inferior rectus from the superior oblique, the clinician asks the patient to first look out (or lateral) to orient the visual gaze axis perpendicular to the superior oblique muscle fiber direction, then down.
How does the inferior oblique move the eye?
Four muscles attach to the surface of the eye and work together to move the eyeball in a vertical (upward) direction. 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.
Is the inferior oblique muscle vertical or horizontal?
When the eye is adducted, the oblique muscles are the prime vertical movers. Elevation is due to the action of the inferior oblique muscle, while depression is due to the action of the superior oblique muscle. The oblique muscles are also primarily responsible for torsional movements.
Where does the inferior oblique attach?
The inferior oblique muscle attaches proximally to the medial floor of the orbit just posterior to the orbital rim near the nasolacrimal canal and distally on the lateral, posterior quarter of the eyeball. The muscle crosses posterior to the superior-inferior axis of the eyeball inferior to the inferior rectus muscle.
What is the use of inferior oblique muscle?
The inferior oblique muscle externally rotates, elevates, and abducts the eye.
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 inferior oblique muscle?
Extraocular Muscles The inferior oblique is the only extraocular muscle to have its anatomic origin in the anterior orbit. The muscle runs from the medial corner of the orbit to the lateral aspect of the globe, its length approximately paralleling the tendon of insertion of the superior oblique muscle.
What movement 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.
Which is the shortest EOM?
The inferior oblique muscle has the shortest tendon of all the extraocular muscles (0-1 mm).
What is the superior oblique tendon?
The superior oblique muscle is the longest and thinnest of the extraocular muscles because of its long (2.5 cm) tendon of insertion. 30. The tendon of insertion changes direction as it passes through the trochlea to run in a posterior direction and lies inferior to the superior rectus muscle.
Which way does the inferior rectus move the eye?
The inferior rectus is an extraocular muscle that attaches to the bottom of the eye. It moves the eye downward. The medial rectus is an extraocular muscle that attaches to the side of the eye near the nose. It moves the eye inward toward the nose.
How do the superior and inferior oblique muscles move the eye?
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.
When the eyeballs rotate down the inferior oblique muscle contracts?
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.
What is the H test for eyes?
The test itself is simple. Your eye healthcare provider or technician will ask you to sit up straight while you stare at an object in front of you, which is usually a pen, fixation light, or small picture held 12 and 16 inches away. They will move the object up and down and side to side in an H-shaped pattern.
What is the internal oblique muscle?
Internal abdominal oblique is a muscle found on the lateral side of the abdomen. It is broad and thin. it forms one of the layers of the lateral abdominal wall along with external oblique on the outer side and transverse abdominis on the inner side. Its fibers are obliquely oriented hence the name.
What is oblique eye muscle?
The superior oblique is a fusiform (spindle-shaped) muscle belonging to the extraocular group of muscles. It originates near the nose. Along with the other extraocular muscles, it performs the role of controlling eye movements.
What is Intorsion and extorsion of eye?
Elevation and depression of the eye are termed sursumduction (supraduction) and deorsumduction (infraduction), respectively. Incycloduction (intorsion) is nasal rotation of the vertical meridian; excycloduction (extorsion) is temporal rotation of the vertical meridian.
What is the function of inferior rectus?
The inferior rectus has a primary action of depressing the eye, causing the cornea and pupil to move inferiorly. The inferior rectus originates from the Annulus of Zinn and courses anteriorly and laterally along the orbital floor, making an angle of 23 degrees with the visual axis.
