A patient is unable to close her right eye. Physical examination reveals weakness of the right orbicularis oculi. Which of the following additional symptoms would likely also be present?
**Core Concept**
The orbicularis oculi muscle plays a crucial role in eyelid closure, and its weakness can lead to difficulties in shutting the eyelid. This muscle is innervated by the facial nerve (cranial nerve VII), which is responsible for controlling the motor functions of the facial expression muscles.
**Why the Correct Answer is Right**
The weakness of the orbicularis oculi muscle suggests an involvement of the facial nerve, which is responsible for eyelid closure. The facial nerve controls the muscles of facial expression, including those involved in eye closure, such as the orbicularis oculi. A lesion affecting the facial nerve would likely lead to weakness or paralysis of the orbicularis oculi, resulting in incomplete or inability to close the eyelid. This is often accompanied by other symptoms such as drooping of the corner of the mouth (angular weakness), difficulty whistling, or weakness of the upper lip (upper motor neuron lesions) or weakness of the lower face (lower motor neuron lesions).
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not related to the facial nerve or muscle weakness.
* **Option B:** This option is not directly related to the facial nerve or muscle weakness.
* **Option C:** This option might be related to the facial nerve, but it is not the most specific symptom associated with orbicularis oculi weakness.
**Clinical Pearl / High-Yield Fact**
Involvement of the facial nerve can result in a range of symptoms, including weakness or paralysis of the orbicularis oculi, leading to difficulties in eyelid closure. It is essential to examine the patient's facial muscles to assess for any signs of weakness or paralysis, which can help diagnose a range of neurological conditions.
**Correct Answer:** C.