The costovertebral joints are the joints that connect the ribs to the

vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordate ...

. The articulation of the head of the rib connects the head of the rib to the

bodies Bodies may refer to: * The plural of body * ''Bodies'' (2004 TV series), BBC television programme * Bodies (upcoming TV series), an upcoming British crime thriller limited series * "Bodies" (''Law & Order''), 2003 episode of ''Law & Order'' * B ...

of the

thoracic vertebra In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...

Structure

The

costotransverse joint The costotransverse joint is the joint formed between the facet of the tubercle of the rib and the adjacent transverse process of a thoracic vertebra. The costotransverse joint is a plane type of synovial joint which, under physiological conditio ...

connects the tubercle of the rib with the transverse process of the

thoracic vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...

. It is a

synovial joint A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articul ...

. Two convex facets from the head attach to two adjacent vertebrae, at the

inferior costal facet The inferior costal facet (or inferior costal fovea) is a site where a rib forms a joint with the inferior aspect of the body of a thoracic vertebra. In the adjacent picture, the arrow points to an inferior costal facet. The facets are named for t ...

of the superior vertebra, and the

superior costal facet The superior costal facet (or superior costal fovea) is a site where a rib forms a joint with the top of a vertebra. Ribs connect to the thoracic vertebrae at two main points, the inferior and superior costal facets. These connection points are l ...

of the inferior vertebra respectively. This forms the synovial planar (gliding) joint, the articulation of the head of rib, which is strengthened by the

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal l ...

of the head and the intercapital ligament. Articulation of the tubercle is to the

transverse process The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

of the inferior vertebra. This articulation is reinforced by the dorsal

costotransverse ligament A costotransverse ligament is a short fibrous band that connects a rib with the transverse process of vertebra. They are some of the ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ' ...

. The intra-articular ligament of head of rib (interarticular in older texts; ''ligamentum capitis costae intraarticulare'') is situated in the interior of the articulation of head of rib between the superior costal facet and the inferior costal facet. It consists of a short

, a band of fibers, flattened from top to bottom, attached at one end to the crest separating the two

costal facets A costal facet is a site of connection between a rib and a vertebra. The costal facets are located on the vertebrae that the rib articulates with. They are the superior costal facet, the inferior costal facet, and the transverse costal facet. Rib ...

on the head of the rib, and at the other end to the

intervertebral disc An intervertebral disc (or intervertebral fibrocartilage) lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the vertebrae, to act as a ligament to h ...

between the two vertebrae; it divides the joint into two cavities. This ligament is the homologue of the ''conjugate ligament'' present in some

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...

, and uniting the heads of opposite ribs, across the back of the intervertebral fibrocartilage. In the joints of the first, tenth, eleventh, and

twelfth rib The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a ...

s, the intra-articular ligament does not exist; consequently, there is only one cavity in each of these articulations.

Function

The costovertebral joints stabilise the ribs by connection to the vertebral column.

Other animals

The costovertebral joints are very similar in other

, including

cats The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members o ...

References

External links

Diagram at ithaca.edu via web.archive.org
Joints {{musculoskeletal-stub