In complete 3 rd Nerve palsy-a) Eye Deviated Mediallyb) Superior and inferior recti affectedc) Dilated pupild) Ptosise) Conversion/accommodation is lost
**Question:** In complete 3rd Nerve Palsy:
A) Eye Deviated Medially
B) Superior and inferior recti affected
C) Dilated pupil
D) Ptosis
E) Conversion/accommodation is lost
**Core Concept:**
Complete 3rd nerve palsy is a neurological condition caused by the dysfunction of the oculomotor (III) nerve, which controls several muscles of the eye and face, including the levator palpebrae superioris (lid elevator), the superior and inferior rectus (eye movement muscles), and the ciliary ganglion for pupillary dilation.
**Why the Correct Answer is Right:**
In a complete 3rd nerve palsy, all the muscles controlled by the oculomotor nerve are affected. Therefore, the correct answer encompasses the affected muscles:
- Eye Deviation Medially (A): The medial rectus muscle is affected, causing the eye to deviate towards the midline.
- Superior and Inferior Recti Affected (B): Both the superior and inferior rectus muscles are involved, leading to abnormal eye movement and misalignment.
- Dilated Pupil (C): The pupil is not directly controlled by the oculomotor nerve, but the constrictor pupillae muscle is innervated by the oculomotor nerve. In a complete 3rd nerve palsy, pupillary dilation occurs due to the absence of parasympathetic innervation to the constrictor pupillae muscle.
- Ptosis (D): The levator palpebrae superioris muscle is not directly affected in a complete 3rd nerve palsy; therefore, ptosis (eyelid drooping) is not a common feature.
- Conversion/Accommodation is Lost (E): Accommodation and convergence are not directly affected by the oculomotor nerve; they are under the control of other nerves (e.g., parasympathetic innervation for pupillary constriction and accommodation, respectively).
**Why Each Wrong Answer is Incorrect:**
Option A is incorrect because the oculomotor nerve controls not only the medial rectus muscle for eye deviation but also the levator palpebrae superioris muscle for eyelid elevation, which is not affected in a complete 3rd nerve palsy.
Option B is incorrect because while some degree of ptosis (eyelid drooping) can occur in a partial 3rd nerve palsy, it is not a common feature in a complete 3rd nerve palsy.
Option C is incorrect because the pupillary dilation is a result of the absence of parasympathetic innervation to the constrictor pupillae muscle. This is not directly tested in the question, but it is important to note that accommodation and convergence are not directly controlled by the oculomotor nerve, making options E incorrect.
**Clinical Pearls:**
1. A complete 3rd nerve palsy is a result of injury or compression of the oculomotor nerve at its origin, commonly due to tumors, vascular