Thorax: Anatomy & LocationKey facts about the anatomy of the thorax
~ 2 min

The thorax consists of the ribs (costae), sternum (sternum), and thoracic vertebrae (vertebrae thoracicae). It is shaped like a cut cone.


Its anterior wall is formed by the sternum and rib cartilages, the lateral walls by the rib bodies, and the posterior wall by the thoracic vertebrae and the remaining rib parts.

The thorax has two apertures (entry/exit openings).

  • The superior thoracic aperture (apertura thoracis superior) is located between the first thoracic vertebra and the first rib.

Superior thoracic aperture (apertura thoracis superior)
Superior thoracic aperture (apertura thoracis superior)
  • The inferior thoracic aperture (apertura thoracis inferior) is located between the xiphoid process, the costal margin (arcus costalis) and the tenth (according to some sources, twelfth) thoracic vertebra. This aperture is closed by a specific respiratory muscle—the diaphragm.

    Inferior thoracic aperture (apertura thoracis inferior)
    Inferior thoracic aperture (apertura thoracis inferior)
    Costal margin (arcus costalis)
    Costal margin (arcus costalis)

    Between the two adjacent ribs is the intercostal space (spatium intercostale), which is closed by muscles and ligaments.

    Intercostal space (spatium intercostale)
    Intercostal space (spatium intercostale)

    The infrasternal angle (angulus infrasternalis) is formed at the junction of the rib arches with the sternum.

    Infrasternal angle (angulus infrasternalis)
    Infrasternal angle (angulus infrasternalis)

    Between the bodies of the thoracic vertebrae and the internal surface of the ribs the so-called pulmonary groove (sulcus pulmonalis) can be distinguished, to which the lungs adjoin.

    Depending on the body type, there are different types of thoracic cages:

  • The asthenic type is narrow with wide intercostal spaces. The infrasternal angle is <90°.

  • The normosthenic type is of medium width. The infrasternal angle equals =90°.

  • The hyperstenic type is wide, with narrow intercostal spaces. The infrasternal angle is >90°.

Men have a cone-shaped, long and wide chest, and women have a cylindrical, shorter and narrower chest.



vertebrae thoracicae
thoracic vertebrae
apertura thoracis superior
superior thoracic aperture
apertura thoracis inferior
inferior thoracic aperture
arcus costalis
costal margin
spatium intercostale
intercostal space
angulus infrasternalis
infrasternal angle
sulcus pulmonalis
pulmonary groove
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