The cavitas thoracis (thoracic cavity) is divided into three large spaces: the mediastinum (p. 90) and the two cavitates pleurales (p. 112). The cavitas thoracis (thoracic cavity) is divided into three large spaces: the mediastinum (p. 90) and the two cavitates pleurales (p. 112).
The arcus aortae has three major branches: the truncus brachiocephalicus, left a. carotis communis, and left a. subclavia. After the arcus aortae, the aorta begins its descent, becoming the pars thoracica aortae at the level of the angulus sterni and the pars abdominalis aortae once it passes through the hiatus aorticus in the diaphragma.
Aortic dissection
A tear in the inner wall (tunica intima) of the aorta allows blood to separate the layers of the aortic wall, creating a “false lumen” and potentially resulting in life-threatening aortic rupture. Symptoms are dyspnea (shortness of breath) and sudden onset of excruciating pain. Acute aortic dissections occur most often in the pars ascendens aortae and generally require surgery. More distal aortic dissections may be treated conservatively, provided there are no complications (e.g., obstruction of blood supply to the organs, in which case a stent may be inserted to restore perfusion). Aortic dissections occurring at the base of an a. coronaria may cause myocardial infarction.
The v. cava superior is formed by the union of the two vv. brachiocephalicae at the level of the T2–T3 junction. It receives blood drained by the v. azygos system (the v. cava inferior has no tributaries in the thorax).
The body's chief lymph vessel is the ductus thoracicus. Beginning in the abdomen at the level of L1 as the cisterna chyli, the ductus thoracicus empties into the junction of the left vv. jugularis interna and subclavia. The ductus lymphaticus dexter drains to the right junction of the vv. jugularis interna and subclavia.
Fig. 8.10 Thoracic nodi lymphoidei
Transverse section at level of bifurcatio tracheae (T4), superior view. The thoracic nodi lymphoidei can be divided into three broad groups: nodes of the thoracic wall (pink), pulmonary nodes (blue), and mediastinal nodes (green). For details of lymphatics of the mediastinum, see pp. 110–111.
Thoracic innervation is mostly autonomic, arising from the paravertebral trunci sympathici and parasympathetic nn. vagi. There and diaphragma (p. 66) and the nn. intercostales innervate the thoracic wall (p. 70).
The autonomic nervous system innervates smooth muscle, cardiac muscle, and glandulae. It is subdivided into the partes sympathica (red) and parasympathica (blue), which together regulate blood flow, secretions, and organ function.
Clinical box 8.1
