Platysma

A thin, superficial muscle that covers the front of the neck and extends to the lower jaw and chest.

The platysma is a broad, sheet-like muscle located in the subcutaneous tissue of the neck, playing a crucial role in facial expression and neck mobility. It originates from the fascia of the pectoralis major and deltoid muscles and inserts into the mandible and the skin of the lower face. This muscle is primarily innervated by the facial nerve (cranial nerve VII), which enables it to control movements associated with expressions of distress or surprise.

Terminologia Anatomica

platysma

System

Muscular system

Function

The primary function of the platysma is to enable a range of actions involving the lower jaw and neck. When contracted, it can help to depress the mandible, which contributes to opening the mouth and creating expressions of fear or surprise by pulling the corners of the mouth downward. Additionally, the platysma assists in tensing the skin of the neck, which can be especially helpful in movements that require head and neck positioning, such as looking up or down. This muscle also plays a role in thermoregulation, as its contraction can help maintain a stable temperature in the neck area by restricting blood flow during colder conditions.

Location

The platysma is situated in the anterior neck, just beneath the skin and above the deeper layers of muscles and tissues. It extends from the upper chest and shoulder region, specifically from the fascia covering the pectoralis major and deltoid muscles, ascending to the mandible's lower edge. The fibers of the platysma spread outward and upward, contributing to both the anterior and lateral aspects of the neck's appearance. This positioning allows it to interact with nearby structures, such as the sternocleidomastoid muscle and the facial muscles, enhancing its role in neck movements and facial expressions.

Did You Know?

The platysma is one of the few muscles in the body that is mainly responsible for expressions of fear and surprise.
In some animals, the platysma is more developed and plays a significant role in their communication through physical expressions.
The platysma is sometimes targeted in cosmetic procedures for aesthetic improvements of the neck and facial appearance.