All of the following can be caused by 3rd cranial nerve paralysis except? (AIIMS Nov 2011)
|C||Outward deviation of eye|
1. A complete Oculomotor nerve palsy will result in a characteristic down and out position in the affected eye. The eye will be displaced downward, because the superior oblique (innervated by the fourth cranial or trochlear nerve), is unantagonized by the paralyzed superior rectus and inferior oblique and displaced outward, because the lateral rectus (innervated by the sixth or abducens cranial nerve) is unantagonized by the paralyzed medial rectus. The affected individual will also have a ptosis, or drooping of the eyelid, and pupil dilation.
2. It should be borne in mind, however, that the branched structure of the oculomotor nerve means that damage sustained at different points along its pathway, or damage caused in different ways (compression versus loss of blood supply, for example), will result in different muscle groups or, indeed, different individual muscles being affected, thus producing different presentation pattern