Costochondral joints
Juncturae costochondrales
Definition
The costochondral joints are the primary cartilaginous (synchondrosis) articulations between the anterior ends of the ribs and their respective costal cartilages.
Each joint is formed where the sternal end of a rib meets its costal cartilage, allowing for a firm but slightly flexible connection that contributes to the elasticity and movement of the thoracic cage during respiration. The joint surfaces are covered by hyaline cartilage and are united by a perichondrium, without a true joint cavity or synovial lining. These joints are stabilized by the surrounding perichondrium and periosteum, and are protected by overlying muscles such as the external oblique, especially at the lower ribs.
The anatomy of these joints is relatively consistent, but some variability exists, particularly in the lower ribs, where the costal cartilages may have free tips or variable attachments to adjacent cartilages.
References
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
