Facial Anatomy - Muscles
The muscles of facial expression are derivatives of the 2nd pharyngeal arch and are innervated by facial nerve (CN VII). These muscles originate from bone or fascia and insert on skin to provide the movements of facial expression. The muscles of facial expression are enclosed by, or form part of, the superficial musculo-aponeurotic system (SMAS).
The orbital group consists of the obicularis oculi (3 portions), depressors supercilii, and corrugator supercilii (oblique and transverse heads). These muscles provide movement of the eyelid and periorbital skin and are innervated by branches of the facial nerve .
The oral group consists of the obicularis oris, depressor anguli oris, levator anguli oris, zygomaticus major, zygomaticus minor, levator labii superioris, levator labii superioris alaeque nasia, risorius, depressor labii inferioris, mentalis, and buccinator. These muscles provide movement of the lips and are innervated by branches of the facial nerve.
The nasal group consists of the depressor septi, procerus, and the compressor naris and dilator naris of the nasalis. These muscles provide movement of the nose and perinasal skin and are innervated by branches of the facial nerve.
The auricular group consists of the anterior, superior, and posterior auricular muscles. These muscles provide movement of the auricle and are innervated by the temporal and posterior auricular branches of the facial nerve.
The occiptofrontalis, or scalp, group consists of the frontalis, and occipitalis. These muscles provide movement of the eyebrows, forehead, and scalp and are innervated by the temporal and posterior auricular branches of the facial nerve .
The neck group consists of the platysma. It provides movement of the skin of the neck and is innervated by the cervical branch of the facial nerve .
Muscles of Mastication
The muscles of mastication are derivatives of the first pharyngeal arch and are innervated by the mandibular division of the trigeminal nerve (V) . These muscles originate and insert on bone and provide movement of the mandible to enable mastication. The muscles of mastication consist of the temporalis, masseter, medial ptyergoid, and lateral pterygoid .
- American Academy of Ophthalmology. Oculoplastics/Orbit: Facial anatomy Practicing Ophthalmologists Learning System, 2017 - 2019 San Francisco: American Academy of Ophthalmology, 2017.
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