INI-CET 2025

Q: Which nerve is not related to olfaction?

Hypoglossal. ***Hypoglossal (Correct Answer)*** - The **Hypoglossal nerve (CN XII)** is a **purely motor nerve** that innervates the intrinsic and extrinsic muscles of the tongue. - It has **no sensory function** and is **not related to olfaction** in any way. - It does not contribute to smell, taste, or nasal sensation. *Trigeminal (Incorrect)* - The **Trigeminal nerve (CN V)**, particularly its ophthalmic (V1) and maxillary (V2) divisions, provides **general sensory innervation to the nasal mucosa**. - It mediates sensations of **irritation, burning, and cooling** from chemical stimuli (chemesthesis) in the nasal cavity, which accompanies the olfactory experience. - While not true olfaction, it contributes to the overall nasal sensory experience alongside CN I (olfactory nerve). *Glossopharyngeal (Incorrect)* - The **Glossopharyngeal nerve (CN IX)** provides **taste sensation** from the posterior third of the tongue [1]. - While primarily involved in taste (gustation) rather than olfaction, taste and smell are closely integrated in **flavor perception** [1]. - This question tests the distinction between nerves directly involved in nasal/smell sensation versus purely motor nerves. *Vagus (Incorrect)* - The **Vagus nerve (CN X)** provides **taste sensation** from the epiglottis and pharynx. - Like CN IX, it contributes to **flavor perception** through the integration of taste and smell [1]. - It has sensory components related to the aerodigestive tract, making it more related to the broader sensory experience than the purely motor hypoglossal nerve. **Key Concept:** Only the **olfactory nerve (CN I)** is responsible for true olfaction [2]. Among the options given, Hypoglossal is the only purely motor nerve with no sensory role in smell, taste, or nasal sensation.

Q: Which muscles are supplied by the ulnar nerve?

All of the options. ***All of the options*** - The **ulnar nerve** supplies the **intrinsic muscles of the hand**, excluding the three thenar muscles (Abductor pollicis brevis, Flexor pollicis brevis-superficial head, Opponens pollicis) and the lateral two lumbricals (1st and 2nd). - The complete list of intrinsic hand muscles supplied by the ulnar nerve includes all interossei (dorsal and palmar), the hypothenar muscles (Abductor digiti minimi, Flexor digiti minimi brevis, Opponens digiti minimi), the third and fourth lumbricals, the palmaris brevis, the adductor pollicis, and the deep head of the flexor pollicis brevis [1]. *Dorsal interossei* - There are four **dorsal interossei** muscles, responsible for **ABduction** (DAB) of the fingers. - All four dorsal interossei are solely supplied by the **deep branch of the ulnar nerve**. *4th lumbrical* - The **lumbricals** are small muscles that flex the MCP joints and extend the IP joints [1]. - The **medial two lumbricals** (3rd and 4th) are supplied by the **deep branch of the ulnar nerve**, while the lateral two are supplied by the median nerve. *Abductor digiti minimi* - This is one of the three **hypothenar muscles** (muscles of the little finger eminence). - Like the other hypothenar muscles, it is exclusively supplied by the **deep branch of the ulnar nerve** [1].

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Anatomy

2 questions

Q201

Which nerve is not related to olfaction?

Q202

Which muscles are supplied by the ulnar nerve?