Facial muscles

Facial muscles are a group of about 20 flat skeletal muscles lying under the facial skin. These muscles are responsible for facial expressions, and are unique in that they are attached to the skin and bones of the face.

Illustration of the facial muscles from Gray's Anatomy

Structure

The facial muscles are divided into two groups: the muscles of facial expression and the muscles of mastication. The muscles of facial expression are located superficially, while the muscles of mastication are located deeper within the face.

Muscles of Facial Expression

The muscles of facial expression are derived from the second branchial arch. They are innervated by the facial nerve (cranial nerve VII). These muscles include:

• Orbicularis oculi
• Orbicularis oris
• Zygomaticus major
• Zygomaticus minor
• Buccinator
• Platysma

Muscles of Mastication

The muscles of mastication are responsible for the movements of the jaw during chewing and speaking. They are innervated by the trigeminal nerve (cranial nerve V). These muscles include:

• Masseter
• Temporalis
• Medial pterygoid
• Lateral pterygoid

Function

The facial muscles allow for a wide range of facial expressions, including smiling, frowning, and winking. They also play a key role in non-verbal communication and social interaction.

Clinical significance

Damage to the facial nerve can result in facial paralysis, leading to an inability to move the muscles of facial expression. This can result in a loss of facial expression and difficulty with tasks such as eating and speaking.

See also

• Facial nerve
• Facial paralysis
• Bell's palsy