Skeletal System 7.8

thoracic cage

thoracic cage

includes the ribs, the thoracic vertebrae, the sternum, and the costal cartilages that attach the ribs to the sternum

functions of the bones in the thoracic cage

support the pectoral girdle and upper limbs

protect the viscera in the thoracic and upper abdominal cavities

play a role in breathing

ribs

12 pairs of ribs

first 7 are true (vertebrosternal ribs) that join the sternum

remaining 5 are called false ribs bc their cartilages do not reach the sternum directly

upper three false ribs (vertebrochondral ribs) join the cartilages of the seventh rib

last two (or sometimes three) rib pairs are called floating ribs (vertebral ribs) bc they have no cartilaginous attachments to the sternum

structure of a rib

long, slender shaft, which curves around the chest and slopes downward

posterior end has an enlarged head where the rib articulates with a facet on the body of its own vertebra and with the body of the next higher vertebra

a tubercle, close to the head of the rib, articulates with the transverse process of the vertebra

sternum

breastbone

located along the midline in the anterior portion of the thoracic cage

3 parts:

1. upper manubrium

2. middle body

3. lower xiphoid process

manubrium articulates with the clavicles by facets on its superior border

the thoracic cage includes 12 pairs of , the ___ vertebrae, ___ cartilages, and one ___

ribs, thoracic, costal, sternum

posteriorly, the ___ of a rib articulates with the body of a thoracic vertebra and the ___ of a rib articulates with the transverse process of the vertebra

head; tubercle

functions of the thoracic cage

protects the heart, assists in breathing, supports the upper limbs

what structure articulates with the sternum?

costal cartilages