Rib
Ribs are classed as flat bones which usually have a protective role in the body. Humans have 24 ribs, in 12 pairs. All are attached at the back to the thoracic vertebrae, and are numbered from 1–12 according to the vertebrae they attach to. The first rib is attached to thoracic vertebra 1 (T1). At the front of the body most of the ribs are joined by costal cartilages to the sternum. The ribs connect to the vertebrae with two joints, the costovertebral joints.
Hominid dental morphology evolution
Today, humans possess 32 permanent teeth with a dental formula of . This breaks down to two pairs of incisors, one pair of canines, two pairs of premolars, and three pairs of molars on each jaw. In modern day humans, incisors are generally spatulate with a single root while canines are also single rooted but are single cusped and conical. Premolars are bicuspid while molars are multi-cuspid. The upper molars have three roots while the lower molars have two roots.