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.
Human leg
The leg from the knee to the ankle is called the "crus" or "cnemis" . The calf is the back portion, and the tibia or shinbone together with the smaller fibula make up the front of the lower leg.
Evolution has provided the human body with two distinct features: the specialization of the upper limb for visually guided manipulation and the lower limb's development into a mechanism specifically adapted for efficient bipedal gait. While the capacity to walk upright is not unique to humans, other primates can only achieve this for short periods and at a great expenditure of energy. The human adaption to bipedalism is not limited to the leg, however, but has also affected the location of the body's center of gravity, the reorganisation of internal organs, and the form and biomechanism of the trunk. In humans, the double S-shaped vertebral column acts as a great shock-absorber which shifts the weight from the trunk over the load-bearing surface of the feet. The human legs are exceptionally long and powerful as a result of their exclusive specialization for support and locomotion — in orangutans the leg length is 111% of the trunk; in chimpanzees 128%, and in humans 171%. Many of the leg's muscles are also adapted to bipedalism, most substantially the gluteal muscles, the extensors of the knee joint, and the calf muscles.