Facial muscles

Facial muscles

Head

Lateral head anatomy
Details
Nerve facial nerve
Identifiers
Latin musculi faciei
Dorlands
/Elsevier		 m_22/12548981
TA A04.1.03.001
FMA 71288

Anatomical terms of muscle

The facial muscles are a group of striated skeletal muscles innervated by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles.

Structure

The facial muscles are subcutaneous (just under the skin) muscles that control facial expression. They generally originate from the surface of the skull bone (rarely the fascia), and insert on the skin of the face. When they contract, the skin moves. These muscles also cause wrinkles at right angles to the muscles’ action line. Use of these muscles is noted during an extraoral examination, assuring function of the nerve to these muscles.[1]

Innervation

The facial muscles are innervated by facial nerve (cranial nerve VII), with each nerve serving one side of the face.[1] In contrast, the nearby masticatory muscles are innervated by the mandibular nerve, a branch of the trigeminal nerve (cranial nerve V).

Development

The facial muscles are derived from the second branchial/pharyngeal arch.

List of muscles

The facial muscles include:[2]

The platysma is innervated by the facial nerve. Although it is mostly in the neck and can be grouped with the neck muscles by location, it can be considered a muscle of facial expression due to its common innervation.

The stylohyoid muscle, stapedius and posterior belly of the digastric muscle are also innervated by the facial nerve, but are not considered muscles of facial expression.

Clinical relevance

An inability to form facial expressions on one side of the face may be the first sign of damage to the nerve of these muscles. Damage to the facial nerve results in facial paralysis of the muscles of facial expression on the involved side. Paralysis is the loss of voluntary muscle action; the facial nerve has become damaged permanently or temporarily. This damage can occur with a stroke (cerebrovascular accident or CVA), Bell palsy, or parotid salivary gland cancer (malignant neoplasm) because the facial nerve travels through the gland. The parotid gland can also be damaged permanently by surgery or temporarily by trauma. These situations of paralysis not only inhibit facial expression but also seriously impair the patient’s ability to speak, either permanently or temporarily.[1]

See also

References

  1. 1 2 3 Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 89
  2. ↑ Kyung Won, PhD. Chung (2005). Gross Anatomy (Board Review). Hagerstown, MD: Lippincott Williams & Wilkins. p. 364. ISBN 0-7817-5309-0.
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