Joints of the Sternum

Joints of the ribs | Main Anatomy Index | Intercostal area

Joints of the Sternum

• The joints of the sternum are between its parts.
• There are two articulations: the manubriosternal (sternomanubrial) and xiphisternal (xiphosternal) joints.

The Manubriosternal Joint (p. 43)

• This articulation is between the manubrium and the body of the sternum.
• The sternal angle indicates the manubriosternal joint. In adults this is a secondary cartilaginous joint (symphysis).
• The bony articular surfaces are covered with hyaline cartilage, and a fibrocartilaginous disc connects the articulation bones.

• In about 30% of people, the central part of the cartilaginous disc undergoes absorption, forming a cavity, but this is not a joint cavity.
• The manubriosternal joint is strengthened by anterior and posterior fibrous ligaments, which extend across the joint from the manubrium to the body.
• In most people, the manubriosternal joint moves slightly during respiration.

The Xiphisternal Joint (p. 44)

• This articulation between the xiphoid process and body of the sternum is a primary cartilaginous joint (synchrondrosis); these bones are united by hyaline cartilage.
• By 40 years of age, the xiphoid and this cartilage have usually ossified.
• In most elderly people, the xiphisternal joint is ossified and the xiphoid is fused with the body of the sternum.

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