Platysma

The platysma is a superficial muscle that overlaps the sternocleidomastoid muscle.

It is a broad sheet arising from the fascia covering the upper parts of the pectoralis major and deltoid; its fibers cross the clavicle, and proceed obliquely upward and medially along the side of the neck.

Fibres at the front of the muscle from the left and right sides intermingle together below and behind the symphysis menti; the junction where the two lateral halves of the mandible are fused at an early period of life. It is not a true symphysis as there is no cartilage between the two sides of the mandible. Fibres at the back of the muscle cross the mandible, some being inserted into the bone below the oblique line, others into the skin and subcutaneous tissue of the lower part of the face. Many of these fibers blend with the muscles about the angle and lower part of the mouth.

Sometimes fibers can be traced to the zygomaticus, or to the margin of the orbicularis oris. Beneath the platysma, the external jugular vein descends from the angle of the mandible to the clavicle.

After the skin incision and preparation, a cervical retractor system is applied. The blades are available in PEEK and Titanium. A counter retractor can be used. The subcutaneous tissue is separated from the platysma cranially, caudally and medially, and the platysma is also separated following the direction of its fibres. The margins of the platysma can be held apart with the retractor or with two surgical forceps.

Retractors should not be placed deeper than the platysma to avoid injury to recurrent laryngeal nerve, which runs between the esophagus and trachea. Blunt retractors are used to avoid internal jugular vein injury

Improvements in imaging technology, particularly computed tomographic angiography (CTA), have altered the management of patients with penetrating neck trauma. Although some centers still advocate routine exploration for all zone 2 neck injuries penetrating the platysma, many civilian centers in the United States have adopted a policy of selective exploration based on clinical and radiographic examination.

Because of fatal complications associated with penetrating neck trauma, Mahmoodie et al recommend early neck exploration in unstable cases or when injuries are deeper than the platysma ¹⁾.