Paralysis of which muscle lead to hyperacusis in Bell's palsy: September 2008

Ans. C: Stapedius Bell's palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side. Several conditions can cause a facial paralysis, e.g., brain tumor, stroke, and Lyme disease. However, if no specific cause can be identified, the condition is known as Bell's palsy. Named after Scottish anatomist Charles Bell, who first described it, Bell's palsy is the most common acute mononeuropathy and is the most common cause of acute facial nerve paralysis. Idiopathic unilateral facial nerve paralysis is usually self-limiting. The trademark is rapid onset of paial or complete palsy, usually in a single day. It can occur bilaterally resulting in total facial paralysis in around 1% of cases in GBS, sarcoidosis, sickle cell disease etc. Patient may complain of noise intolerance due to stapedial palsy or loss of taste due to involvement of chorda tympani.