The platysma muscle is a band of tissue found in the chest, neck, and facial region.
This muscle covers a portion of a neck muscle known as the sternocleidomastoid. The platysma muscle is expansive in size, with a broad width that spans the collarbone, or clavicle, and the side of the neck. Its point of origination is the upper portions of the pectoral, or chest, and the deltoid, or shoulder. The muscle narrows in size once it reaches the neck, extending upwards to the lower jawbone, known as the mandible. Platysma muscle fibers are found throughout the lower region of the face, including the skin, tissue, and other bones of the mouth.
In some instances, the platysma muscle can travel as far upwards as the cheekbone and the lower region of the muscle that controls eyelid movements, known as the orbicularis oculi. The facial nerve allows the muscle to move. With the platysma muscle, an individual can slightly part the mouth and draw out the corners of the lips to the side and down. These movements are used when negative emotions like fear and fright are conveyed.