Platysma Muscle

Description

Running as a thin sheet within the superficial cervical fascia, the platysma spans from the subcutaneous tissue over the upper thorax and clavicle, then ascends anteromedially across the lateral neck to approach the inferior border of the mandible and the skin of the lower face. A lateral female profile places its posterior margin near the anterior border of the trapezius, while its more anterior fibers drape superficial to the sternocleidomastoid and over the carotid triangle region. Superiorly, fibers blend with perioral and lower facial soft tissues, and inferiorly they interdigitate with the superficial fascia overlying the pectoral region. The relationship is superficial throughout. No deep tendon is present. Understanding platysma anatomy matters because it is one of the few muscles with primary insertion into dermis, so its tone directly influences cervical skin contour and the appearance of vertical platysmal bands with aging. Surgeons rely on this layer as a landmark during subplatysmal facelifts, neck lifts, and anterior neck dissections, where staying either superficial or deep to the platysma changes the risk profile for the marginal mandibular branch and cervical branch of the facial nerve. In the trauma setting, platysma violation remains a classic threshold for penetrating neck injury evaluation, since a wound deep to this muscle raises concern for injury to the carotid sheath contents and aerodigestive tract. Designed for teaching the superficial musculoaponeurotic system (SMAS) continuum from upper chest to mandible, this illustration supports head and neck anatomy courses, surgical atlases, and aesthetic medicine training materials that cover botulinum toxin injection planning and platysmaplasty. It also works well for patient education handouts explaining neck banding and lower face laxity in a female habitus. Anatomical accuracy verified by SciePro's Medical Advisory Board.