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This video demonstrates a bilateral medial recession + inferior oblique recession surgery in a 13-year-old female patient, who had a V-Pattern esotropia. Surgery location: on-board the Orbis Flying Eye Hospital in Binh Dinh, Vietnam. Rudolph Wagner, Rutgers New Jersey Medical School Transcript (To translate please select your language to the right of this Continue. Width inferior transfer of the medial rectus muscle. Inferior Oblique Overaction ETIOLOGY Inferior oblique overaction may be primary and of unknown etiology, or secondary to a congenital superior oblique palsy, as covered in Chapter 19. Primary inferior oblique overaction is commonly associated with congenital. The extraocular muscles are located within the orbit, but are extrinsic and separate from the eyeball itself. They act to control the movements of the eyeball and the superior eyelid. There are seven extraocular muscles - the levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, lateral rectus, inferior oblique.

The superior oblique muscle, or obliquus oculi superior, is a fusiform muscle originating in the upper, medial side of the orbit (i.e. from beside the nose) which abducts, depresses and internally rotates the eye. It is the only extraocular muscle innervated by the trochlear nerve (the fourth cranial nerve).

Structure[edit]

The superior oblique muscle loops through a pulley-like structure (the trochlea of superior oblique) and inserts into the sclera on the posterotemporal surface of the eyeball. It is the pulley system that gives superior oblique its actions, causing depression of the eyeball despite being inserted on the superior surface.

The superior oblique arises immediately above the margin of the optic foramen, superior and medial to the origin of the superior rectus, and, passing forward, ends in a rounded tendon, which plays in a fibrocartilaginous ring or pulley attached to the trochlear fossa of the frontal bone.

The contiguous surfaces of the tendon and ring are lined by a delicate mucous sheath, and enclosed in a thin fibrous investment.

The tendon is reflected caudally, laterally, and inferiorly beneath the superior rectus to the lateral part of the bulb of the eye, and is inserted onto the scleral surface, behind the equator of the eyeball, the insertion of the muscle lying between the superior rectus and lateral rectus.

Function[edit]

The primary (main) action of the superior oblique muscle is intorsion (internal rotation),^[1] 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. Extraocular muscles other than the medial rectus and lateral rectus have more than one action due to the angle they make with the optical axis of the eye while inserting into the eyeball. The superior and inferior oblique muscles make an angle of 51 degrees with the optical axis.^{[citation needed]}

The depressing action of superior oblique (making the eye look down towards the mouth) is most effective when the eye is in an adducted position. This is because as the eye is abducted (looks laterally), the contribution made by superior oblique to depression of the eye decreases, as the inferior rectus muscle causes this movement more directly and powerfully. The main muscle for abduction is the lateral rectus, so although superior oblique contributes to a downwards and lateral eye movement, testing this motion would not be specific enough as inferior and lateral recti muscles would also be tested. Therefore, during neurological examinations, the superior oblique is tested by having the patient look inwards and downwards, testing only the depressing action of the muscle. This is a source of confusion on the subject as although clinical testing asks the patient to adduct and depress the eye, anatomically the muscle depresses and abducts it.

The great importance of intorsion and extorsion produced by the two oblique muscles can only be understood when it is considered with regards to the other muscle actions present. The two obliques prevent the eye from rotating about its long axis (retina to pupil) when the superior and inferior rectus muscles contract. This is because the orbit does not face directly forwards- the centre-line of the orbit is a little over 20 degrees out from the mid-line. But because the eyes do face forwards, when acting alone, as well as making the eye look up, superior rectus causes it to rotate slightly about the long axis, so the top of the eye moves medially (intorsion). Similarly, in addition to making the eye look down, inferior rectus would cause the eye to rotate about the long axis so the top of the eye moves slightly laterally (extorsion), if acting alone. Clearly this is undesirable as our vision would rotate when we looked up and down. For this reason, these two rectus muscles work in conjunction with the two obliques. When acting alone, superior oblique causes intorsion, inferior oblique, extorsion. Hence, when inferior rectus contracts so we look down, superior oblique also contracts to prevent extorsion of the eye, and when superior rectus contracts so we look up, inferior oblique contracts to prevent intorsion, thus the undesired rotatory actions of the inferior and superior recti about the long axis of the eye are cancelled out. This keeps our vision horizontally level, irrespective of eye position in the orbit.^[2]

Clinical significance[edit]

Superior oblique palsy is a common complication of closed head trauma. Restriction of superior oblique movement due to an inelastic tendon is found in Brown syndrome, leading to difficulty elevating the eye in the adducted position.

Superior oblique myokymia is an uncommon neurological condition caused by vascular compression of the trochlear nerve resulting in repeated, brief, involuntary episodes of movement of the eye.

Surgical operations of the superior oblique include tenotomy, recession, silicone expander lengthening, split tendon lengthening, tucking, and the Harada-Ito procedure.

Additional images[edit]

• Eye movement of lateral rectus muscle, superior view

• Eye movement of medial rectus muscle, superior view

• Eye movement of inferior rectus muscle, superior view

• Eye movement of superior rectus muscle, superior view

• Eye movement of superior oblique muscle, superior view

• Eye movement of inferior oblique muscle, superior view

• Anterior view

• Nerves of the orbit. Seen from above.

• Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.

References[edit]

This article incorporates text in the public domain from page 1022 of the 20th edition ofGray's Anatomy(1918)

1. ^https://emedicine.medscape.com/article/1189759-overview#a3
2. ^Dr. Robert Acland's Atlas of Human Anatomy, University of Louisville. Volume 5: Head and Neck Part 2, Section 5: The Eye and its Surroundings.

External links[edit]

• Anatomy figure: 29:01-03 at Human Anatomy Online, SUNY Downstate Medical Center

Medial Rectus And Inferior Oblique Dmg Muscle

It is important for the oculoplastic surgeon, or anyone performing orbital surgery, to have a strong understanding vascular anatomy. While significant variability exists^[1], this article will detail the standard vascular anatomy of the human orbit.

Blood supply to the orbital arises primarily from the ophthalmic artery - the first branch off of the internal carotid as it emerges from the cavernous sinus on the medial side of the clinoid process. The ophthalmic artery has many branches which may be separated into 2 groups: *Orbital Group *Ocular Group

Orbital Group

• Lacrimal artery: Runs along the lateral wall of the orbit and supplies the lacrimal gland. Terminal branches of the lacrimal artery include the superior and inferior lateral palpebral arteries which supply the lateral upper and lower eyelids and conjunctiva.
• Supraorbital artery: In the orbit supplies the supeior rectus and levator palpebral muscles. It then passes through the supraorbital foramen and its terminal branches supply the eyebrow and forhead.
• Anterior ethmoidal artery: In the orbit supplies the superior oblique muscle. Also supplies the anterior and middle ethmoidal cells, frontal sinus, lateral wall nose, and nasal septum.
• Posterior ethmoidal artery: Passes through the posterior ethmoidal canal, supplying the posterior ethmoidal cells.
• Internal palpebral artery: Terminal branches include superior and inferior medial palpebral arteries. These vessels supply the lacrimal sac and eyelids creating an anastomosis with the two lateral palpebral branches from the lacrimal artery.
• Frontal artery: Leaves the orbit at its medial angle above the trochlea and supplies the forehead and scalp creating an anastomosis with the supraorbital artery terminal branches.
• Nasal artery: Supplies the superior lacrimal sac and nose.

Ocular Group

• Short ciliary artery: Supply the choroid and cilliary processes.
• Long ciliary artery: Supply the anterior segment and form anastomoses/collateralization with extraocular muscles branches.
• Central retinal artery: Branches off of the posterior 1/3 of the ophthalmmic artery and enters the dural sheath of the optic nerve about 13mm behind the globe. Supplies the retina.
• Muscular arteries: Splits into superior and inferior branches. The superior branch supplies the levator palpebral muscle, superior rectus, superior oblique and a portion of the lateral rectus. The inferior branch supplies the medial rectus, inferior rectus and inferior oblique. This inferior branch also gives off most of the anterior ciliary arteries.

Note: Anastomoses to the periorbit are also formed via the facial and superficial temporal branches of the external carotid.

Orbital Veins

• Superior Ophthalmic Vein: Provides the main venous drainage of the orbit. Originates in the superonasal quadrant of the orbit and extends posteriorly through the medial part of the superior orbital fissure into the cavernous sinus.
• Inferior Ophthalmic Vein: Originates at the floor and medial wall of the orbit and provides drainage for the inferio orbit.
• Vortex Veins: Venous drainage of the uveal tract and pierce the sclera posterior to the equator of the globe. Superior vortex veins (lateral and medial) drain into the superior ophthalmic vein and the inferior vortex veins (lateral and medial) drain into the inferior ophthalmic vein.

Medial Rectus And Inferior Oblique Dmg Exercises

1. ↑Hayreh SS. Orbital vascular anatomy. Eye (2006) 20, 1130–1144. doi:10.1038/sj.eye.6702377

Medial Rectus Eye