Ribs 1-12

Tubercle of a rib/costal tubercle

A subtle enlargement on the body of most ribs near the junction of the body and neck

Cartilage of a rib/costal cartilage

The cartilage attached to the anteromedial end of the body of a rib

Costal neck

The constricted portion of a rib immediately adjacent to its head

Floating ribs

The costal cartilage of ribs 11 and 12 end within the musculature of the body wall. These last two false ribs on each side are called floating ribs since their costal cartilages make no contact with the sternum (i.e. they "float" in the body wall).

Costal arch

The costal cartilages of ribs 8-10 attach to each other and to that of rib 7 to form the ipsilateral arch. This forms the palpable, inferior aspect of the thoracic cage on each side of the trunk.

Costal body

The major portion of a rib beginning at and including the tubercle, costal angle, and costal grove

Angle of a rib/costal angle

The portion of the body of a rib which makes the tightest bend

False ribs

The remaining ribs on each side (ribs 8-12) that do not have costal cartilage end directly on the sternum

True ribs

The ribs (1-7) whose costal cartilages on each side join the sternum directly

Costal head

The rounded portion which articulates with the costal fovea of the bodies of the vertebrae. Heads of ribs 1, 10, 11, and 12 typically articulate only with the thoracic vertebra of the same number (and thus, they have undivided articular surfaces)

Groove of a rib/costal groove

The subtle linear depression along the internal surface of the inferior border of a rib which transmits the intercostal vessels and nerve

Ribs 1-12

There are normally 12 pairs of ribs numbered. Some individuals have one more rib or one less rib on one or both sides of the thorax. The first 7 pairs are progressively longer and the last 5 are progressively shorter (compared to those immediately above). Each rib consists of three main parts.