A patient presents with unilateral facial paralysis. Is temporomandibular disorder (TMD) the most likely diagnosis?

• A. TMD
• B. Otitis externa
• C. Bell's palsy
• D. Stroke

Answer: (C)

Unilateral facial paralysis points to a problem with the facial nerve (a peripheral CN VII palsy) rather than dysfunction of the jaw joint. Temporomandibular disorder involves the jaw muscles and the temporomandibular joint, causing jaw pain, tenderness, clicking or popping, and limited opening. It does not produce a true weakness of all the facial muscles on one side.

Bell's palsy fits the presentation because it is a peripheral facial nerve palsy that causes acute weakness of the entire side of the face, including the forehead and the eye, leading to drooping at the mouth and difficulty closing the eye. This pattern is the hallmark of CN VII involvement, not TMJ dysfunction.

Stroke could present with facial weakness, but typically the forehead is not fully involved in a cortical (UMN) pattern, and there are often additional neurological signs. Otitis externa would mainly produce ear symptoms (pain, discharge) and facial weakness only if the nerve is affected by nearby inflammation, which is less typical than Bell's palsy in isolated facial paralysis.

So, when the presentation is unilateral facial paralysis, Bell's palsy is the most likely diagnosis rather than TMD.