Rib cage

Thorax , compares thoracis, make up the thoracic spine, ribs (12 pairs) and sternum.

The thorax forms the thoracic cavity, the cavitas thoracis, which has the shape of a truncated cone, which is turned by a wide base downward, and the truncated tip - upward. In the chest, the front, back and side walls, the upper and lower opening, which define the thoracic cavity, are distinguished.

Structure of the chest.

The anterior wall is shorter than the other walls, formed by the sternum and cartilage of the ribs . Located obliquely, it protrudes more towards its lower sections than the upper ones. The posterior wall is longer than the anterior, formed by the thoracic vertebrae and
Rib portions from heads to corners; Its direction is almost vertical.

On the external surface of the posterior wall of the chest, between the spinous processes of the vertebrae and the corners of the ribs, two troughs are formed on both sides - dorsal furrows: they have deep back muscles . On the inner surface of the chest, between the protruding bodies of the vertebrae and the corners of the ribs, two troughs are also formed: pulmonary furrows, sulci pulmonales; They are joined to the vertebral part of the rib surface by the lungs.

The lateral walls are longer than the anterior and posterior, formed by the bodies of the ribs and are more or less convex.
The spaces bounded above and below by two adjacent ribs, in front - the lateral edge of the sternum and behind - the vertebrae, called the intercostal space, spatia intercostalia; They are made by ligaments, intercostal muscles and membranes.
The thorax, compages thoracis, bounded by the indicated walls, has two holes - the top and bottom, which begin with apertures.

The upper aperture of the thorax, apertura thoracis superior, is smaller than the lower one, it is bounded from the front by the upper edge of the handle, from the sides by the first ribs and from behind by the body of the thoracic vertebrae . It has a transversely oval shape and is located in a plane tilted from behind in front and down. The upper edge of the sternum is at the level between the II and III thoracic vertebrae.

The lower aperture of the thorax, apertura thoracis inferior, is bounded in front by the xiphoid process and formed by the cartilaginous ends of the false ribs by the rib arch, from the sides by the free ends of the XI and XII ribs and the lower edges of the XII ribs, and at the back by the body of the XII thoracic vertebra .

The costal arch, arcus costalis, in the xiphoid process forms an open root under the sternum, angulus infrasternalis.

The shape of the chest in different people is different (flat, cylindrical or conical). In persons with a narrow thorax, the podkrudin angle is sharper and the intercostal space is wider, and the thorax itself is longer than in persons with a broad thorax. The thorax in men is longer, wider and more conical than in women.
The shape of the chest also depends on age.

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