RT Book, Section A1 Sonne, James W.H. SR Print(0) ID 1174512415 T1 Thorax T2 Photographic Dissector for Students of Physical Therapy: A Step-by-Step Approach YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN 9781260457933 LK accessphysiotherapy.mhmedical.com/content.aspx?aid=1174512415 RD 2024/11/07 AB While performing the thoracic cavity dissection, you will be following many of the structures of the neck as they enter through the superior thoracic aperture. Of particular importance is observing the course of the vagus, phrenic, and recurrent laryngeal nerves. The thorax is composed of three enclosed cavities, the mediastinum for the heart, and two plural cavities, one for each lung. As these cavities are enclosed, they depend on movement and reorientation for their drainage. Infections and inflammation, as well as inactivity, can cause a build-up of fluid within these areas.