Organization of the ribs

Are long, thin-curved slightly twisted arches of bone.

• 12 pairs of ribs
  
  
• Three categories:
  
  a) vertebrosternal: 1-7, Extend from vertebrae to the sternum
  
  b) Vertebrocostal: Run between vertebrae and common costal cartilage
  
  c) vertebral: 11 and 12 , sometimes called floating ribs, free anterior ends

Atypical ribs

• Short, Broad,C-shaped
• 2 surfaces- superior and inferior
• 2 borders- lateral and medial
• has only one articular facet for articulation with the T1 vertebra
• A prominent scalene tubercle on the superior surface   

• Has a curvature similar to the one of first rib, but is thinner , much less curved and about twice as long as the first rib
• Has a broad rough eminence, the tuberosity for the serratus anterior muscle

• Are short
• Are capped with cartilage
• Have a single facet on their heads
• Have no neck
• Have no tubercle
• The 11 th rib has a slight angle and a shallow costal groove