Repeated USMLE Questions Step 1 - 154

A 73 year old man is brought to the emergency room for dizziness and nystagmus. Examination reveals loss of sensation on the left side of his face and the right side of his body. He has hoarseness of voice and drooping of his right eyelid. The right side of the face is drier than the left side. He is referred for CT scan on his head.

What is the site of lesion responsible for hoarseness of this patient?

A- Inferior cerebellar peduncle

B- Spinal nucleus of fifth cranial nerve

C- Nucleus Ambiguus

D- Lateral spinothalamic tract






Answer

Nucleus ambiguus contains the cell bodies of the nerves that innervate soft palate, larynx and pharynx. Lesions of the nucleus ambiguus affect one or more of nerve supply to these organs. Hoarseness of voice in this case is most probably due to defect of the innervation to the larynx caused by lesion of the nucleus ambiguus.

The correct answer is C