**Question:** U/L injury to hypoglossal nerve leads to all except -

A. Facial palsy
B. Trigeminal nerve dysfunction
C. Speech impairment
D. Cervical spondylosis

**Core Concept:**
Hypoglossal nerve is a cranial nerve that controls the muscles involved in tongue movement. It is a mixed nerve that carries both motor and sensory fibers. The hypoglossal nerve arises from the brainstem, specifically from the lateral pontine nucleus, and projects to the tongue muscles. U/L injury refers to a lesion involving the upper limb, typically due to a cervical spine injury.

**Why the Correct Answer is Right:**
When the hypoglossal nerve is damaged, the affected individual may experience weakness or paralysis of the tongue muscles. This results in difficulty with tongue movement, particularly dorsally and laterally.

**Why Each Wrong Option is Incorrect:**
A) Facial palsy (Bell's palsy) occurs due to a lesion involving the seventh cranial nerve, which innervates the facial muscles responsible for facial expressions, not tongue movement.

B) Trigeminal nerve dysfunction would involve the fifth cranial nerve, which is responsible for sensation in the face and motor control of the muscles involved in mastication. It is not related to tongue movement.

C) Speech impairment would involve motor or sensory lesions affecting the nerves involved in speech production and understanding, such as the cortico-bulbar and cortico-spinal tracts, and the auditory system. These are not directly related to tongue movement.

D) Cervical spondylosis (degenerative changes in the cervical spine) would lead to radicular symptoms, such as pain, numbness, or weakness in the affected limb, rather than affecting the tongue muscles.

**Clinical Pearl:**
In clinical practice, it is essential to consider the differential diagnoses of tongue movement disorders, which may involve various nerve pathways. A thorough history, clinical examination, and appropriate imaging investigations can help to identify the specific nerve or system involved and guide appropriate management.