Question

A patient underwent a left submandibular gland excision during which the hypoglossal nerve was injured. Which of the following deficits would be seen in this case?

• A. Deviated tongue to the contralateral side
• B. Deviated tongue to the same side
• C. Inability to protrude tongue
• D. Loss of taste in posterior 1/3rd of the tongue

Hint:

Injury to the hypoglossal nerve typically causes ipsilateral (same side) tongue weakness and deviation toward the injured side when protruding the tongue.

Answer 1

The Correct Option is B

Deviated tongue to the contralateral side: This is incorrect. Injury to the hypoglossal nerve (CN XII) causes weakness or paralysis of the muscles on the affected side of the tongue. If the left hypoglossal nerve is injured, the tongue will deviate toward the left side (same side), not the contralateral side.
Deviated tongue to the same side: This is correct. The hypoglossal nerve controls the intrinsic and extrinsic muscles of the tongue. If the left hypoglossal nerve is damaged, the left side of the tongue will become weaker and cause the tongue to deviate toward the left side (same side) when the patient attempts to protrude it.
Inability to protrude tongue: This is incorrect. While the hypoglossal nerve injury leads to weakness, it does not typically cause an inability to protrude the tongue completely. The tongue may be weak and deviate, but some movement is still possible.
Loss of taste in posterior 1/3rd of the tongue: This is incorrect. Loss of taste in the posterior 1/3rd of the tongue is caused by injury to the glossopharyngeal nerve (CN IX), not the hypoglossal nerve. Thus, the correct answer is Deviated tongue to the same side (2), as damage to the hypoglossal nerve causes tongue deviation toward the affected side.