Ribs

Twelve pairs of ribs and sternum together with the thoracic spine form a thorax.

The ribs (costae) are long, narrow, thin, curved bone plates. In front, the osseous part of the rib extends into the cartilaginous part - cartilago costalis. The seven upper pairs of ribs connecting at the front with the sternum are called true ribs (costae verae). The ribs VII, IX and X with their cartilages are connected to the cartilaginous part of the overlying rib - these are the false ribs (costae spuriae). The ribs XI and XII end in the abdominal muscles. These ribs are called oscillating (costae fluctuantes).

At the posterior end of each rib there is a thickening - the head of the rib (caput costae), which connects to the corresponding costal fossa on the thoracic vertebrae. On the head II-X of the ribs there is a crest of the head of the rib (crista capitis costae), since each of these ribs connects to two costal fossae. The head of the XI and XII ribs do not have a ridge.

A narrow neck of the rib (collum costae) leading to its body (corpus costae) is located ahead of the rib head. I-X ribs on the border of the neck and body have a tuberculum costae with an articulation site for articulation with a transverse process of the corresponding vertebra. The flattened body of the rib has a convex outer and concave inner surface. On the inner surface down along the rib there is a furrow of the rib (sulcus costae), to which intercostal vessels and nerve adhere. A little lateral the tubercle is the rounded corner of the rib (angulus costae).

The first edge is different from the rest of the ribs. It has upper and lower surfaces, lateral and medial margins. Not far from the junction with the breastbone on the upper surface is the tubercle of the anterior staircase (tuberculum musculi scaleni anterioris). In front of the tubercle is a groove of the subclavian vein (sulcus venae subclaviae), and behind the tubercle is the furrow of the subclavian artery {sulcus arteriae subclaviae).