ABSTRACT
DEVELOPMENT e muscles of facial expression are derived from the second pharyngeal arch during embryologic development and thus receive their motor innervation from cranial nerve VII, the facial nerve. e primary function of these muscles is to protect the facial orices and the organs located in their proximity from mechanical damage (orbicularis oculi), from ingestion of harmful substances (orbicularis oris), and to aid the uptake of food (levator anguli oris, levator labii superioris, depressor anguli oris, and depressor labii inferioris muscles) and air (nasalis, levator alaeque nasi, depressor septi nasi muscles). Previously important muscles for the movement of the ears, which were used, for example, during hunting or defense, can be still found as rudiments (e.g., the auricularis muscles).
