Figure 2. Figures 1, 2. (1) Axial drawing of the fasciae and spaces of the infrahyoid neck. The superficial layer of the DCF (red line) encircles the neck deep to the superficial fascia. The middle layer of the DCF (blue line) encircles the visceral space and contains the thyroid gland, trachea, and esophagus. The deep layer of the DCF (green line) forms the posterior wall of the retropharyngeal space and danger space and delineates the prevertebral space. Note that the three layers of the DCF form the carotid sheath. (Adapted and reprinted, with permission, from reference 2.) (2) Sagittal drawing of the layers of the DCF and the spaces of the neck with extension to the thorax. Red line = superficial layer of the DCF, blue line = middle layer of the DCF, green line = deep layer of the DCF. The visceral space is contained between the two blue lines and is continuous from the cervical area to the superior mediastinum. The posterior margin of the visceral space serves as the anterior wall of the retropharyngeal space. This compartment continues caudally into the thorax to the posterior mediastinum (P) (T3). A = anterior mediastinum, Ao = aorta, E = esophagus, M = middle mediastinum, PA = pulmonary artery, T = trachea. (Adapted and reprinted, with permission, from reference 2.)