For the individual bones, see Rib. Ribs are described based on their location and connection with the 3 2 1 ribs. All ribs are attached posteriorly to the thoracic vertebrae and are numbered accordingly one to twelve. Ribs that articulate directly with the sternum are called true ribs, whereas those that do not articulate directly are termed false ribs.
The terms true ribs and false ribs describe rib pairs that are directly or indirectly attached to the sternum. These ribs are relatively small and delicate, and include a cartilaginous tip. Each rib consists of a head, neck, and a shaft. All ribs are attached posteriorly to the thoracic vertebrae. The neck of the rib is the flattened part that extends laterally from the head. The neck is about 3 cm long. Its anterior surface is flat and smooth, whilst its posterior is perforated by numerous foramina and its surface rough, to give attachment to the ligament of the neck.
On the posterior surface at the neck, is an eminence—the tubercle that consists of an articular and a non-articular portion. The articular portion is the lower and more medial of the two and presents a small, oval surface for articulation with the transverse costal facet on the end of the transverse process of the lower of the two vertebrae to which the head is connected. At this point, the rib is bent in two directions, and at the same time twisted on its long axis. The distance between the angle and the tubercle is progressively greater from the second to the tenth ribs. The area between the angle and the tubercle is rounded, rough, and irregular, and serves for the attachment of the longissimus dorsi muscle. Costal groove position on a central rib.
