The chest or thorax is the upper part of the human trunk. It consists of the thoracic skeleton, cavea thoracis (sternum, ribs, thoracic vertebrae, and clavicles) with soft tissues coating it and the thoracic cavity, cavitas thoracis.
The superior limit of chest goes from the jugular notch along the sternoclavicular joints and clavicles up to acromioclavicular joints from where the straight lines are constructed to the spinal process of the VII cervical vertebra.
The inferior limit is drawn from the base of the xiphoid process along the edges of the costal arches to the X pair of ribs and further through the ends of the XI-XII pair of ribs to the spinal process of the XII thoracic vertebra.
The thoracic skeleton consists of the thoracic part of the spinal column, 12 pairs of ribs, and the sternum.
The superior thoracic aperture, apertura thoracis superior is formed by the superior border of the jugular notch of sternum, first ribs and the shaft of the first thoracic vertebra (T I).
Through the superior aperture (thoracic inlet), the right and left cervical pleura and the apexes of the lungs run out into the supraclavicular region; and the trachea, oesophagus, vessels, nerves and fascial-cellular spaces pass through.
The inferior thoracic aperture, apertura thoracis inferior is closed by the diaphragm that separates the thoracic cavity from the abdominal one. The oesophagus, vessels and nerves pass through the diaphragmatic apertures.
The thoracic cavity, cavitas thoracis is a space bordered by the superior aperture, the thoracic cage and the diaphragm.
The limits of the chest and the thoracic cavity do not coincide, for the diaphragm protrudes with its cupula into the thoracic cage along with the abdominal organs lying in the left and right hypochondria (liver, spleen, etc.). The left and right cervical pleurae as well as the apexes of lungs exit into the regions of neck over the clavicle.