Platysma

Anatomy

Origin:
Superficial fascia of the upper part of the thorax, covering pectoralis minor and deltoid.

Insertion:
Lower border of the body of the mandible, skin of the lower face, lateral half of the lower lip, and the buccal angle.

Key Relations:
-Platysma runs from the root of the neck across the clavicle to the mandible.
-Platysma overlies the sternocleidomastoid and external jugular vein.

Functions

-Tenses the skin of the neck
-Draws the lower lip and corners of the mouth inferiorly e.g. as in expressions of horror, sadness and fright.
-Weakly depresses the mandible.
-Also active during sudden inspiration.

Supply

Nerve Supply:
Cervical branch of facial nerve (CN 7).

Blood Supply:
-Submental branch of the facial artery
-Suprascapular artery of thyrocervical trunk.

Clinical

Spasmodic contractions of this muscle can occur in nervous tics.

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