n. a curved, slightly twisted, strip of bone forming part of the skeleton of the thorax, which protects the heart and lungs. There are 12 pairs of ribs. The head of each rib articulates with one of the 12 thoracic vertebrae of the backbone; the other end is attached to a section of cartilage (see costal cartilage). The first seven pairs – the true ribs – are connected directly to the sternum by their costal cartilages. The next three pairs – the false ribs – are attached indirectly: each is connected by its cartilage to the rib above it. The last two pairs of ribs – the floating ribs – end freely in the muscles of the body wall. Anatomical name: costa.
Subjects: Medicine and Health.