Thoracic Cage Checklist
Thoracic cage The thoracic, or rib, cage consists of the sternum, costal cartilages, ribs, and thoracic vertebrae.
The thoracic cage protects internal organs, is an attachment site for muscles, and is involved with respiration.
Sternum The sternum, or breastbone, is the midline, anterior part of the thoracic cage. It consists of three bones which fuse together in the elderly.
The sternum 1. is the midline, anterior attachment site for the clavicles and the costal cartilages of MOST ribs. 2. is an attachment site for chest and neck muscles moving the arms and neck. 3. is an attachment site for the linea alba. 4. protects internal organs, especially the heart. 5. can be moved during respiration, increasing thoracic volume.
Manubrium Superior bone of the sternum. The clavicles attach to the manubrium.
Body Main, middle bone of the sternum.
Sternal angle The joint between the manubrium and body; marks the level at which the cartilage of the second rib joins the sternum.
Xiphoid process Inferior bone of the sternum; an attachment site for the linea alba, an anchor point for abdominal muscles.
Ribs and costal cartilages Twelve pairs of flat bones forming most of the thoracic cage. They are responsible for most of the strength of the thoracic cage.
The costal cartilages attach MOST ribs to the sternum. They allow the thoracic cage to change shape during respiration.
Together, the ribs and costal cartilages 1. surround and protect thoracic organs. 2. are attachment sites for muscles. 3. can be moved, resulting in changes of thoracic volume during respiration.
Thoracic Cage Checklist
True ribs The superior seven pairs of ribs which attach directly to the sternum by their costal cartilages. Also called vertebrosternal ribs.
False ribs The inferior five pairs of ribs. They are called false ribs because they do not attach to the sternum.
Ribs 8, 9, and 10. False ribs that attach to the costal cartilage of the seventh rib. Also called vertebrochondral ribs.
Ribs 11 and 12 False ribs that have no anterior attachment. Also called floating or vertebral ribs.
Head of rib The rib head has articular facets by which it attaches to the bodies of thoracic vertebrae. The rib head can move during respiration.
Tubercle of rib The tubercle of the rib attaches to the transverse process of a thoracic vertebra. The tubercle has an articular facet allowing movement of the rib during respiration.