The average human skeleton has 206 bones: 32 in each hand, 31 in each leg, 29 in the skull, 26 in the spine, and 25 in the chest. For some people, the number of bones slightly deviates from normal – for example, you may have several more bones in your fists or feet or one or more bones may be missing.
Some bone of the skeleton are connected by joints. There are several types of joints. The stationary joints (sutures) connect the bones firmly, like on the skull.
Semi-movable joints provide some flexibility, as in the bones of the spine. Movable joints provide great flexibility in several motion levels, like the shoulders. The male and female skeleton differ very little. One difference is that male bones are generally slightly longer and harder. Furthermore, the cavity in the male pelvis is narrower than the cavity of the female pelvis through which the child’s head and the body must pass (when the person is giving birth).
In the last months of pregnancy, a very small part of the skeleton of the baby contains real bones. Then most of the bones actually consist of cartilage. As the child grows, the cartilage becomes a real bone – a process known as “ossification”. The areas of ossification occur at a certain time during the growth of a healthy child. Only shaped bones can be seen on the X-ray (the cartilage is virtually invisible); therefore, the ossification is easily detected on the X-ray.