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Thoracic Cage Checklist

Thoracic cage The thoracic, or , cage consists of the , costal , , and .

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 which fuse together in the elderly.

The sternum 1. is the midline, anterior attachment site for the and the costal cartilages of MOST ribs. 2. is an attachment site for chest and muscles moving the and neck. 3. is an attachment site for the linea alba. 4. protects internal organs, especially the . 5. can be moved during respiration, increasing thoracic volume.

Manubrium Superior of the sternum. The clavicles attach to the manubrium.

Body Main, middle bone of the sternum.

Sternal angle The between the manubrium and body; marks the level at which the of the second rib joins the sternum.

Xiphoid 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 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 of the rib attaches to the transverse process of a thoracic . The tubercle has an articular facet allowing movement of the rib during respiration.