**Question:** In pupillary reflex, nerve tested is -

A. Ciliary nerves
B. Oculomotor nerves
C. Trigeminal nerves
D. Abducens nerves

**Correct Answer:** B. Oculomotor nerves

**Core Concept:** The pupillary reflex is a vital component of the autonomic nervous system that controls the size of the pupil in response to light. It is mediated by two pairs of cranial nerves: oculomotor nerves (III) and parasympathetic nerves (II).

**Why the Correct Answer is Right:** The oculomotor nerves (III) are responsible for the pupillary response. They are part of the autonomic nervous system and supply the iris and ciliary body, which regulate pupil diameter. The parasympathetic nerves (II) also contribute to the pupillary response, primarily through the action of the pupillary light reflex, which is mediated by the parasympathetic portion of the pupillary reflex.

**Why Each Wrong Option is Incorrect:**

A. Ciliary nerves (A): These nerves are part of the sympathetic system and primarily control the ciliary body, iris, and lens, affecting accommodation and ciliary body secretion. They are not involved in the pupillary reflex.

B. Abducens nerves (VI): These nerves control the extraocular muscles responsible for eye movement, specifically lateral rectus muscle, and are not related to the pupillary reflex.

C. Trigeminal nerves (V): These nerves are responsible for sensory and motor functions of the face, not related to the pupillary reflex.

**Clinical Pearl:** Understanding the pupillary reflex helps medical students and doctors assess neurological functions, particularly the oculomotor nerves, in patients with neurological disorders. A disturbance in pupillary reflex can be an indicator of brainstem lesions or involvement of the oculomotor or parasympathetic pathways.