Head and neck muscles (chewing, facial, and throat muscles)

Platysma

Musculus platysma

Origin

Subcutaneous connective tissue over the fascia covering pectoralis major and deltoid, at the level of the upper ribs/shoulder

Insertion

Lower border of the mandible, skin of the lower half of the face and fibers continuing into orbicularis oris and other facial expression muscles

Function

Tenses the skin of the neck, pulls the corners of the mouth down and assists depression of the lower jaw; plays a role in expressions of tension or disgust

Innervation

Facial nerve (CN VII), cervical branch

Movement & chain

Contributes to expressive facial movements (such as a grimace) and to pulling the mouth corner downward, together with depressor anguli oris.

Palpation

Clearly visible and palpable as vertical bands in the neck when the jaw is pulled firmly downward and the mouth corners are pulled laterally-downward.

Clinical

Important surgical landmark in neck surgery and trauma: a wound penetrating through platysma is classified as penetrating neck trauma and requires further investigation.

Segmental innervation

Motor via the facial nerve (VII); no direct spinal segment.

In clinical practice

Used in aesthetic medicine as a target area for botulinum toxin injections against 'platysma bands' in the neck.

Region in the model

Head and neck muscles (chewing, facial, and throat muscles)