How do you test the inferior oblique muscle?

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.

How does the H test work?

The test itself is simple. Your eye doctor 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.

How does superior oblique abduct the eye?

Cranial Nerves III, IV, and VI When the eye is in adduction, this muscle exerts a more or less direct downward pull and depresses the eye. When the eye is in abduction, the superior oblique muscle pulls the 12 o’clock meridian of the iris toward the nose, rotating the globe around an anteroposterior (Y) axis.

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.

How does the superior oblique muscle work?

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).

What is the action of the inferior oblique muscle?

The inferior oblique muscle externally rotates, elevates, and abducts the eye.

What is the function of inferior oblique muscle?

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 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.

When testing extraocular movements What would the patient be asked to?

You are asked to sit or stand with your head up and looking straight ahead. Your provider will hold a pen or other object about 16 inches or 40 centimeters (cm) in front of your face. The provider will then move the object in several directions and ask you to follow it with your eyes, without moving your head.

How is the function of the superior oblique muscle tested?

Amongst students and teaching staff on numerous occasions. turns the eye down and out. However, if was tested clinically by asking combined action of inferior and lateral recti. This is particularly so as (looking laterally). Therefore by asking the patient to look down and in

How are the muscles of the eye tested?

Clinical Testing. For example, both the superior rectus and inferior oblique muscles will elevate the eyeball; both the inferior rectus and superior oblique will depress the eyeball. To discriminate muscle or nerve functions from one another, the clinician can trap one muscle and test its functional pair.

Where does the superior oblique line of pull pass?

The superior oblique line of pull passes medial to the axis of rotation of the eye3. As a adduction. Therefore we test the CN IV by moving the eye ‘down and in’. acting independently. In clinical practice this is seldom seen as it is unusual to have ocular nerve palsies that spare the trochlear nerve. 1. Ahmed HU, Ali S. A case of mistaken muscles.

What happens to the eye after superior oblique muscle contraction?

For a period after the willed muscle contraction, the trochlear nerve continues to discharge so that the superior oblique muscle fails to relax, causing the eye to remain intorted and depressed, which leads to diplopia. After a short period, this abnormal nerve activity ceases and the eye returns to its normal position.