Bone · Chest

Third rib

The first of the typical ribs, and so the template for ribs three to nine: a head with two facets that straddle the disc between two vertebrae, a narrow neck, a tubercle articulating with the transverse process behind, a sharp angle where the shaft turns forward, and a costal groove along the lower inner border sheltering the intercostal vein, artery and nerve in that order from above down. Its outer surface, with the fourth and fifth, gives origin to pectoralis minor. Everything below repeats this plan with only gradual changes in length and slope.