Joints of the Ribs

Bones of the thoracic wall | Main Anatomy Index | Joints of the sternum

The Costovertebral Joints

• A typical rib articulates with the vertebral column at two joints: (1) the joints of the heads of the ribs and (2) the costotransverse joints.
• Typically, the head of a rib articulates with the sides of the bodies of two thoracic vertebrae, and the tubercle articulates with the tip of a transverse process.
• The costovertebral joints are the plane type of synovial joint that allows for gliding or sliding motions.

Joints of the Head of the Ribs (p. 39)

• The head of each typical rib articulates with the demifacets of two adjacent vertebrae and the intervertebral disc between them.
• The head articulates with the superior part of the corresponding vertebra, the inferior part of the vertebra superior to it, and the adjacent intervertebral disc.

• The crest of the head is attached to the intervertebral disc by an intraarticular ligament. It is located within the joint and divides it into two synovial cavities.

• There are exceptions to this general arrangement. The 1^st, sometimes the 10^th, and usually the 11^th and 12^th ribs are connected only to their own vertebral bodies. In these cases, there are no intraarticular ligaments and the joint cavities are not divided.

• An articular capsule surrounds each joint and connects the head of the rib with the circumference of the joint cavity.
• The capsule is strongest anteriorly where a radiate ligament fans out from the anterior margin of the head of the rib to the sides of the bodies of two vertebrae and the intervertebral disc between them.
• The heads of the ribs are connected so closely to the vertebral bodies that only slight gliding movements occur at the joints of the heads of the ribs.

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The Costotransverse Joints (pp. 39-40)

• The tubercle of a typical rib articulates with the facets on the tip of the transverse process of its own vertebra to form a synovial joint.
• These small joints are surrounded by thin articular capsules, which are attached to the edges of the articular facets.

• A lateral costotransverse ligament, passing from the tubercle of the rib to the tip of the transverse process, strengthens the joint at each side.
• In addition, a costotransverse ligament unties the posterior surface of the neck of the rib to the anterior surface of the transverse process.

• A superior costotransverse ligament joins the crest of the neck to the transverse process superior to it.
• The aperture between this ligament and the vertebral column permits passage of the spinal nerve and the dorsal branch of the intercostal artery.

• The 11^th and 12^th ribs do not articulate with transverse processes and have freer movements as a result.

• The strong costotransverse ligaments binding these joints limit their movements to slight gliding. However, the tubercles of the superior six ribs are convex and fit into concavities on the transverse processes.
• As a result, some superior and inferior movements of the tubercles are associated with rotation of the ribs.

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The Sternocostal Joints (p. 40)

• The 1^st to 7^th ribs articulate via their costal cartilages with the lateral borders of the sternum. The first pair of costal cartilages articulates with the sternum at primary cartilaginous joints (synchondroses).
• The costal cartilages are united directly to the hyaline cartilage in the depressions located art the superolateral margins of the manubrium of the sternum.

• The 2^nd to 7^th pairs of costal cartilages articulates with the sternum at synovial joints, but joint cavities are often absent in the inferior ones.
• The thin, weak articular capsules of these joints are strengthened anteriorly and posteriorly by radiate sternocostal ligaments.
• These thin, broad membranous bands pass from the costal cartilages to the anterior and posterior surfaces of the sternum, forming a felt-like covering for the sternum.

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The Costochondral Joints (p. 41)

• Each rib has a cup-shaped depression on its anterior end into which its costal cartilage fits.
• The rib and its costal cartilage are firmly bound together by the continuity of the periosteum of the rib with the perichondrium of the costal cartilages.
• No movement normally occurs at these joints.

The Interchondral Joints (p. 41)

• The articulations between the adjacent borders of the 6^th and 7^th, 7^th and 8^th, 8^th and 9^th costal cartilages are plane synovial joints.
• Each of these articulations is enclosed within an articular capsule that is lined with a synovial membrane.
• Interchondral ligaments strengthen the joints.
• The articulation between the 9^th and 10^th costal cartilages is a fibrous joint.

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