Facial nerve EMG responses are best recorded from which muscles?

The best muscles to record facial nerve EMG responses from are the orbicularis oris and orbicularis oculi muscles. These muscles are innervated directly by the facial nerve (cranial nerve VII) and are critical for assessing its function during procedures involving the facial nerve, such as neurosurgery or plastic surgery.

Recording from the orbicularis oris allows for the evaluation of the lower facial function, particularly for lip movement and closure, while the orbicularis oculi provides insight into eyelid function. These muscles are sensitive indicators of facial nerve integrity because they will respond to stimulation of the facial nerve, allowing clinicians to monitor nerve function during surgery.

Although the masseter muscle is innervated by the trigeminal nerve and the stylomastoid foramen is an anatomical landmark rather than a muscle, the facial nerve travels through that region. Thus, using the orbicularis muscles is specifically beneficial for direct monitoring of facial nerve activity during intraoperative procedures, making them the most suitable choice for EMG responses related to facial nerve function.