What nerve Innervates inferior oblique?

What nerve Innervates inferior oblique?

The inferior oblique is innervated by the inferior division of the oculomotor nerve, which enters the muscle on its upper surface.

How do you test for inferior oblique?

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.

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 motor nuclei of these cranial nerves connect to the brain stem, which coordinates eye movements.

What is entrapment of inferior rectus?

Entrapment. Inferior rectus entrapment. Orbital fractures are typically caused by blunt periocular trauma and are one of the most common types of facial fractures [1]. An important complication of orbital fractures is entrapment of extraocular muscles and orbital fat in a trapdoor fracture.

What nerve controls the inferior rectus muscle?

The inferior rectus is innervated by the lower division of cranial nerve III (oculomotor).

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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.

How does 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.

What movement does the inferior oblique do?

[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.

What kind of muscle is the inferior oblique?

The inferior oblique is an extraocular muscle, and is attached to the maxillary bone (origin) and the posterior, inferior, lateral surface of the eye (insertion). The inferior oblique is innervated by the inferior branch of the oculomotor nerve.

What is Trochlear nerve palsy?

Diseases or injuries to the fourth cranial nerve can cause the superior oblique muscle to be paralyzed. The name for this condition is fourth nerve palsy. Other names for it are superior oblique palsy and trochlear nerve palsy. You may have fourth nerve palsy from birth, or you may develop it later.

How does superior oblique depress the eye?

The superior oblique muscle, therefore, originates functionally from the trochlea at the superior medial orbital rim and inserts on the top of the globe behind its equator. When the eye is in adduction, this muscle exerts a more or less direct downward pull and depresses the eye.

When the eyes 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 EOM entrapment?

ORBITAL FLOOR. The most common indication for emergent repair of an orbital floor fracture is extraocular muscle entrapment. This injury is common in the pediatric patient whose orbital floor is more apt to greenstick rather than down-fracture, and then bounce back, entrapping the inferior rectus muscle.

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How do you treat a blowout fracture?

What can be done for a simple blowout fracture?

  1. ice to decrease swelling.
  2. decongestants to aid in the drainage of blood and fluid accumulating in the sinuses.
  3. avoidance of nose blowing to prevent pressure from propelling the sinus contents into the orbit.
  4. oral steroids in some cases to decrease swelling and scarring.

What is orbital compartment syndrome?

Orbital compartment syndrome is an uncommon, ophthalmic surgical emergency characterized by an acute rise in orbital pressure. When intraorbital tension rises, damage to ocular and other intraorbital structures, including irreversible blindness, may occur if not promptly treated.

What nerve innervates the superior oblique muscle?

The trochlear nerve (IV) exits from the caudal portion of the midbrain and supplies the superior oblique muscle. In distinction to all other cranial nerves, the trochlear nerve exits from the dorsal surface of the brainstem and crosses the midline to innervate the superior oblique muscle on the contralateral side.

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 a result of entrapment of the inferior muscles that support the globe?

Entrapment of the inferior rectus muscle would be noted as an inability of the globe to roll in a vertical plane. On observation, the patient may not be able to look upward with the affected eye.

Is superior oblique palsy hereditary?

Four pedigrees, each with two or more cases of congenital superior oblique palsy among immediate family members, are presented. Except for a single case report in 1926, this disorder has not been known to occur in a hereditary manner.

What happens if the trochlear nerve is damaged?

Injury to the trochlear nerve cause weakness of downward eye movement with consequent vertical diplopia (double vision). The affected eye drifts upward relative to the normal eye, due to the unopposed actions of the remaining extraocular muscles.

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What causes trochlear nerve palsy?

The most common cause of congenital trochlear nerve palsies is congenital cranial dysinnervation syndrome, followed by an abnormal superior oblique tendon. The most common cause of acquired isolated fourth nerve palsy, after idiopathic, is head trauma.

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 oculomotor nerve palsy?

Oculomotor nerve palsy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. As the name suggests, the oculomotor nerve supplies the majority of the muscles controlling eye movements (4 out of the 6 extracocular muscles. All except the Lateral Rectus and Superior Oblique).

What are oblique eyes?

What do the oblique muscles in the eye do?

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).

Which muscles are obliques?

Oblique muscle refers to two abdominal muscles the external and internal obliques. These provide trunk flexion and rotation. The external oblique is the thickest and runs from the lower ribs to the iliac crest.

What is the largest muscle in the lower leg?

The calf muscle, on the back of the lower leg, is actually made up of two muscles:

  • The gastrocnemius is the larger calf muscle, forming the bulge visible beneath the skin. …
  • The soleus is a smaller, flat muscle that lies underneath the gastrocnemius muscle.

What is internal oblique?

Internal oblique. 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.