- One of the 12 paired arches of bone which form the skeletal structure of the chest wall (the rib cage). The ribs attach to the building blocks of the spine (vertebrae) in the back. The 12 pairs of ribs consist of: True ribs: The first seven ribs attach to the sternum (the breast bone) in the front and are known as true ribs (or sternal ribs). False ribs: The lower five ribs do not directly connect to the sternum and are known as false ribs. The upper three false ribs connect to the costal cartilages of the ribs just above them. The last two false ribs, however, usually have no ventral attachment (no anchor at all in front) and are called floating, fluctuating or vertebral ribs.
* * ** * *riboflavin; ribose
* * *rib 'rib n any of the paired curved bony or partly cartilaginous rods that stiffen the lateral walls of the body of most vertebrates and protect the viscera, that occur in mammals exclusively or almost exclusively in the thoracic region, and that in humans normally include 12 pairs of which all are articulated with the spinal column at the dorsal end and the first 10 are connected also at the ventral end with the sternum by costal cartilages see FALSE RIB, FLOATING RIB, TRUE RIB
* * *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.
* * *(rib) 1. costa (def. 1). 2. something resembling this bone.
Medical dictionary. 2011.