Purpose: The youthful neck presents with a transition from a vertical to a more horizontal direction typically at the hyoid level. The platysma is the only neck muscle that crosses from the chest to the face. We undertook this anatomic investigation to determine the underlying causes for the direction changes of this muscle at the level of the hyoid and mandible and their contribution to the youthful neck.
Methods: The anatomy of the neck retaining ligaments was studied in 20 facial halves (ages ranging from 18 to 87). Dissection was carried in a systematic approach from supra-platysmal to sub-platysmal plane in 17 facial halves. The relationship of the ligaments to the platysma and its attachments to the skin from deeper structures were sequentially photographed and documented.
Results: The hyoid ligament originates from the hyoid and courses superficially to insert into the skin at the cervicomental angle. Its relationship to the platysma varies with the level of decussation. The submental ligament is present at the inferior surface of the anterior mandible beneath the submental crease. Osteocutaneous ligaments are also consistently present at the angle of the mandible. Fasciocutaneous ligaments and adhesions provide additional support.
Conclusion: The retaining ligaments of the neck are constant and predictable structures that afford a close relationship of the platysma to the hyoid and mandible. This association provides acute transitions between neck aesthetic units. Understanding platysmal anatomy and ligamentous support will allow execution of the most logical strategy to restore balance and harmony to this delicate area.