Muscles that are Affected by Bell’s Palsy:
Frontalis - responsible for the production of facial expressions such as: raising of the eyebrows, wrinkling of forehead, moving the scalp posteriorly and/or back.
Orbicularis oculi - Simply put it, blinking. It has the ability to close and open the eyelids. Furthermore, it is also responsible for the production of tears (from the eye into the nasolacrimal duct system).
Orbicularis oris - closes the mouth as well as protrudes the lips.
Buccinator - Whistling can be an example of this. It helps with compressing cheeks against the teeth.
Platysma muscles - the action of pulling down the mandible opens the mouth which also pulls the corners of the lips out to the side and down. Kind of like the action of frowning.
Mechanism of Muscle Weakness
Bell’s palsy is a condition that causes weakness or paralysis in the muscles of one side of the face. Simply put, half of the face of a person drops. This is because the facial nerve (the 7th cranial nerve) has been damaged without any known cause. However, experts say that the condition is related to viruses/infections, diabetes, high blood pressure and many more which prevents the transmission of nerves to muscles.
Other Symptoms
Symptoms may include: drooling, dry eyes and excessive tearing in the other eye, loss of taste and headache.