Description
The joints of the head of the ribs are formed where the facets (or demifacets) of the head of the rib articulate with their corresponding vertebral body, the body of the vertebra above, and the intervening intervertebral discs. For example, the fifth rib articulates with the superior costal facet of the body of the fifth vertebra, the inferior costal facet of the body of the fourth vertebra, and the intervertebral disc between these vertebrae. Note that the heads of the 1st, 10th (sometimes), 11th, and 12th ribs only articulate with one vertebral body of the same number. The joints of the head of the ribs are reinforced by the radiate ligaments. Additionally, an intraarticular ligament bisects the synovial joint in two. The first, tenth, eleventh, and twelfth ribs only articulate with its corresponding vertebral body, thus producing only a single synovial joint.