Platysma

Platysma muscle is a broad superficial fascial sheet of thin muscle covering the superior anterior chest, anterior and anterolateral neck and anterolateral mandibular region.

Gross anatomy

The muscle consists of three parts: pars mandibularis, pars labialis and pars modiolaris.

• origin: the fascia of pectoralis major and deltoid muscles
• insertion: lower border of the mandible, the lower lip, and subcutaneous tissue of the lower face

Actions

• tenses the skin between the jaw and lateral neck
• assists in lowering the mandible

Arterial supply

• submental branch of the facial artery: commonest
• suprascapular artery

Venous drainage

• anteriorly: small venous tributaries, often via the submental vein, drain into the superior thyroid vein, anterior jugular vein, or facial vein of the internal jugular vein system
• posteriorly: external jugular vein

Innervation

• cervical branch of the facial nerve