human skeleton model
  • 12 pairs 
  • Attached posteriorly to thoracic vertebrae
  • 3 types: true ribs, false ribs, floating ribs
True ribs 
  • Upper 7 pairs attached anteriorly to sternum via costal cartilages
False ribs
  • 8th, 9th and 10th pairs attached anteriorly to each other and to 7th rib via costal cartilages and small synovial joints 
Floating ribs
  • 11th and 12th pairs have no anterior attachment
Typical rib
  • Long twisted flat bone
  • Round smooth superior border
  • Sharp thin inferior border
  • Inferior border forms costal groove which hosts the intercostal vessels and nerve
  • Anterior end of rib attached to costal cartilage
  • Parts: head, neck, tubercle, shaft and angle
  • Head: two facets, one with corresponding vertebral body, other with vertebrae immediately above
  • Neck: constricted portion between head and tubercle 
  • Tubercle: prominence on outer surface of rib, at junction of neck with shaft. Has facet for articulation with transverse process of corresponding vertebra
  • Shaft: thin, flattened, twisted. Inferior border has costal groove
  • Angle: shaft bends sharply forward
Atypical rib 
  • First rib: small, flattened. Scalenus anterior attaches to upper surface and inner border. Anterior to scalenus anterior, subclavian vein crosses rib, posterior to muscle attachment. Subclavian artery and lower trunk brachial plexus cross rib and lie in contact with bone 
  • Cervical rib: rib from anterior tubercle of transverse process of 7th cervical vertebra. .5% humans. Anterior end can be free or attached to first rib by fibrous band or articulate with first rib.