Platysma

The platysma is a wide, flat, superficial neck muscle extending from the lower part of the face to the upper thorax. It is a paired thin and superficial muscle arising from the upper parts of the shoulders and inserting into the mouth area. The platysma partly covers the pectoralis major and deltoid muscles. In the mouth area, this muscle divides in mandibular, labial and modiolar (nodular) parts. 

 

Origin: skin and fascia covering the lower neck and upper anterolateral chest.

Insertion: base of the mandible, and skin over the lower face and the angle of the mouth.

Action: depresses and wrinkles skin of the lower face and the mouth. The platysma also contributes to forced depression of the mandible.

Innervation: cervical branch of the facial nerve (CN VII).

Blood supply: submental artery - a branch of the facial artery, and the suprascapular artery, which arises from the thyrocervical trunk.