HUMAN BODY : skelton

 Skeleton :

   Without the skeleton, the body would fall like a mass. The skeleton is resistant but surprisingly light since it represents only one sixth of the weight in adults. And it has several functions. Its structure of hard bones, elastic cartilages and strong ligaments supports the body, gives it its shape and protects its internal organs; it also serves as an attachment point for the muscles that make us move. It is often divided into two parts, each playing their role : 

 • The axial skeleton (skull, spine, ribs, sternum), is the main framework that supports the body and protects the brain, eyes, heart, and lungs. 

 • The appendicular skeleton consists of the arms and legs attached to the axial skeleton by the shoulders and hips.

Agile hands :

    Playing with a computer mouse is easy on the hand, the most flexible and skillful part of the body. This flexibility is provided by the 27 bones of the wrist, palm and fingers that can be seen on the x-ray radiograph. They allow the hand to perform all kinds of movements, with the help of a few. 30 muscles located, for the most part, in the forearm.

A protective cage :

    Twelve pairs of ribs curve from the spine : ten of them are connected to the sternum by elastic and flexible cartilages, the last two pairs are free. Spine, ribs and breastbone together form a bony cage protecting the delicate organs of the chest and upper abdomen.

An elastic frame :

    If the bones were welded together, the body would be perfectly supported but unable to move. Fortunately, most of them are connected to each other by movable joints making the skeleton flexible. A movement can involve several bones as well as the joints of the feet, legs, back, arms, hands and neck.

The visible skeleton !

    Before, only X-rays could see someone's skeleton. Recently, other means have been found, such as scintigraphy. This process consists in making the patient absorb a radioactive substance which is rapidly assimilated by the bones. We then identify the radiation they emit. While not as clear as x-ray radios, the image provides additional information about the cellular activity of the bones as well as their possible injuries or illnesses.

Baby skull :

    The skull is made up of several bones welded together to form a one-piece structure. But in newborns, these bones are separated by membrane spaces called fontanelles. Fontanelles give elasticity to the skull and thus allow the baby's head to compress slightly at the time of birth. They then gradually ossify until the age of 18 months.

Cartilage :

    The discs separating the vertebrae are just one example of squlette cartilage. There are three types of this elastic and resistant fabric :

 • The fibrous cartilage of the discs makes the spine flexible and absorbs shock during running.

 • Smooth, transparent cartilage covers the ends of the bones at the joints and forms the curved part of the nose.

 • Elastic cartilage is the light structure of the pinna of the ear.

>> A newborn baby has around 350 bones, but the adult only has 206 bones because some have bonded together during growth.