Platysma

Description

Arising from the superficial fascia over the upper thorax and shoulder, the platysma forms a thin muscular sheet that ascends anteriorly and superiorly across the anterolateral neck toward the inferior border of the mandible and lower face in an adult male. In lateral view, its fibers lie superficial to the sternocleidomastoid, with the posterior margin approaching the anterior border of the muscle as it runs from the manubrium and medial clavicle to the mastoid process. Superiorly, the platysma blends with the perioral musculature near the modiolus and lower lip, while inferiorly it spreads over the pectoral region; adjacent bony landmarks include the mandible, maxilla, and nasal aperture. Superficial anatomy, made legible. Clinically, this relationship between platysma and sternocleidomastoid matters when planning anterior cervical exposures and submandibular approaches, where the platysma is the first named muscle encountered after skin and superficial fascia. Surgeons often elevate subplatysmal flaps during neck dissection and facelift procedures, and the plane just deep to the platysma is also where the external jugular vein and cervical branches of the facial nerve are most at risk from traction or transection. The lateral perspective also helps teach platysmal banding and laxity, common targets for botulinum toxin injection and platysmaplasty in aesthetic practice. Use this illustration in head and neck anatomy modules to anchor discussion of superficial fascial planes, cervical surface landmarks, and the interaction between facial expression musculature and neck compartments. It also suits operative atlases and patient education material for rhytidectomy, neck lift, and anterior cervical spine approaches where subplatysmal dissection is described. Anatomical accuracy verified by SciePro's Medical Advisory Board.