Are extraocular muscles antagonistic?

Three antagonistic pairs of muscles control eye movements: the lateral and medial rectus muscles, the superior and inferior rectus muscles, and the superior and inferior oblique muscles.

What is the antagonist muscle of extraocular muscle?

For example, in abduction of the right eye, the right lateral rectus muscle is the agonist; the right superior and inferior oblique muscles are the synergists; and the right medial, superior, and inferior recti are the antagonists.

What are the functions of extraocular muscles?

The Extraocular Muscles

• Moves the eye Upwards (Elevation)
• Rotates the top of the eye towards the nose (intorsion)
• Moves the eye inward (adduction)

What is primary secondary and tertiary actions of extraocular muscles?

The primary actions of the inferior and superior obliques are excyclo and incyclotorsion, their secondary actions are elevation and depression and their tertiary action is abduction.

How many nerves innervate the six extraocular muscles?

The extraocular muscles execute eye movements and are innervated by three cranial nerves. The muscles are attached to the sclera of the eye at one end and are anchored to the bony orbit of the eye at their opposite ends. Contraction of the muscles produce movement of the eyes within the orbit.

What are the 6 extraocular movements?

You are now familiar with the 6 cardinal directions of gaze (right/up; right; right/down; left/up; left; left/down), as well as the remainder of the yoked eye movements (straight up; straight down; convergence).

What are the primary secondary and tertiary actions of superior rectus?

The superior rectus has a primary action of elevating the eye, causing the cornea to move superiorly. This angle causes the secondary and tertiary actions of the superior rectus muscle to be adduction and intorsion (incycloduction).

What is the main function of the trochlear nerve?

The primary function of the trochlear nerves (IV) is also motor, controlling eye movements. These nerves originate in the midbrain, passing through the superior orbital fissures of the sphenoid bone, to reach the superior oblique muscles. The trochlear nerves are the smallest of the cranial nerves.

What are the roles of the extraocular muscles?

The contributions of the six extraocular muscles to vertical and horizontal eye movements. Horizontal movements are mediated by the medial and lateral rectus muscles, while vertical movements are mediated by the superior and inferior rectus and the superior (more…)

How are two antagonistic muscles related in one eye?

In one eye, in two antagonistic muscles, like the lateral and medial recti, contraction of one leads to inhibition of the other. Muscles show small degrees of activity even when resting, keeping the muscles taut. This ” tonic ” activity is brought on by discharges of the motor nerve to the muscle.

What are the muscles that control eye movements?

The Actions and Innervation of Extraocular Muscles. Three antagonistic pairs of muscles control eye movements: the lateral and medial rectus muscles, the superior and inferior rectus muscles, and the superior and inferior oblique muscles.

Are there muscles that conjugate binocular eye movements?

Conjugate binocular eye movements. Yoke muscles are the primary muscles in each eye that accomplish a given version (eg, for right gaze, the right lateral rectus and left medial rectus muscles). Each extraocular muscle has a yoke muscle in the opposite eye to accomplish versions into each gaze position.