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THE THORAX

--12 pairs of ribs attached by ligaments to thoracic vertebrae and the first 10 pairs articulate with costal cartilages at the anterior end

--T1-T7 bear true ribs; have cartilage connections to the sternum

--T8-T12 bear false ribs; have a cartilage connection to the cartilage of rib 7

--T11-T12 bear floating ribs; no connection to the sternum; no facets on transverse processes

--ribs (12 pairs): head attaches to vertebrae; body

--sternum: composed of the manubrium, body, & xiphoid; ossification not complete until age 25; xiphoid not ossified until age 40; care must be used in CPR not to break the xiphoid

--there is a ridge (the sternal angle) where the manubrium joins the body; the second costal cartilage fuses here and this site is a useful origin for rib counting; you can feel ribs 2-5

STERNUM STERNUM
STERNUM STERNUM
RIBS
RIBS
RIBS RIB
RIBS