THORACIC CAGE Chapter 7

Thoracic Cage  Consists of thoracic vertebrae dorsally  Ribs are laterally positioned  Sternum and Costal Cartilage are anterior

 Forms a protective cage around organs found in the thoracic cavity  Provides support for the shoulder girdle and upper limb

Sternum  Known as the breastbone lies anteriorly on the body midline  Flat bone (3 fused – manubrium, body, xyphoid process)  The manubrium (top) articulates with the clavicle and first 2 pairs of ribs  The body (middle) articulates with the rib pairs 2 through 7  The xyphoid process (inferior end) does not articulate with any ribs (forms the V at end of cage)

RIBS  Form the sides of the Thoracic cage with 12 pairs of ribs  Attach posteriorly and curve inferiorly toward the anterior of the body  The top (superior) 7 pairs are classified as true ribs  Attach directly to the sternum via individual costal cartilage  Lower 5 pairs of ribs are classified as “false” ribs  Attach indirectly to the sternum or lack sternal attachment