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For example, the lateral rectus is on the lateral side of the eyeball. When it contracts, the eyeball moves so that the pupil looks outwards. The medial rectus causes the eyeball to look inwards; the inferior rectus downwards and outwards, and the superior rectus upwards and outwards.
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).
Lateral and anterior views of the extraocular muscles also showing common tendinous ring origin and trochlea. Since only a small part of the eye called the fovea provides sharp vision, the eye must move to follow a target. Eye movements must be precise and fast. This is seen in scenarios like reading, where the reader must shift gaze constantly.
The body of the superior oblique muscle is located behind the eyeball, but the tendon (which is redirected by the trochlea) approaches the eyeball from the front. The tendon attaches to the top (superior aspect) of the eyeball at an angle of 51 degrees with respect to the primary position of the eye (looking straight forward). The force of the ...
The lateral rectus is the only muscle supplied by the abducens nerve (CN VI). The neuron cell bodies are located in the abducens nucleus in the pons.These neurons project axons as the abducens nerve which exit from the pontomedullary junction of the brainstem, travels through the cavernous sinus and enter the orbit through the superior orbital fissure.
Then comes the more characteristically described extreme and sustained upward deviation of the eyes. In addition, the eyes may converge, deviate upward and laterally, or deviate downward. The most frequently reported associated findings are backwards and lateral flexion of the neck, widely opened mouth, tongue protrusion, and ocular pain.
A conjugate eye movement is a movement of both eyes in the same direction to maintain binocular gaze (also referred to as “yoked” eye movement). This is in contrast to vergence eye movement, where binocular gaze is maintained by moving eyes in opposite directions, such as going “cross eyed” to view an object moving towards the face.
The term gaze is frequently used in physiology to describe coordinated motion of the eyes and neck. The lateral gaze is controlled by the paramedian pontine reticular formation (PPRF). [1] The vertical gaze is controlled by the rostral interstitial nucleus of medial longitudinal fasciculus and the interstitial nucleus of Cajal. [2]