A healthy, active lifestyle and your skeletal system What is the skeletal system? The skeletal system includes all the bones in the body, from the cranium (skull) to the bones that make up the foot. What does it do? It has three main functions: 1. Movement​
: Where bones meet they form joints. Tendons attach the bones to muscles. 2. Support​
: The skeleton supports the body in a variety of positions ­ standing up, sitting, lying down... 3. Protection​
: The cranium protects the brain.The spine, or vertebral column, protects the spinal chord. The ribs which form the chest protect the heart and lungs. Joints and movement The structure of joints: A joint is a place where two or more bones meet. Is our bodies were not jointed we would be very uncomfortable, and our activities would be extremely restricted. In order to prevent pain through the friction that could be caused by the bones friction, the ends of the bones in a synovial joint are covered with a thick cartilage. Cartilage is elastic. Joints allow movement. For example, the spine is made up of a number of small bones which allow the back to be flexible; a characteristic that allow high jumpers to bend over a bar. Generally speaking, the joints in the upper limbs (​
extremitats​
) allow mobility (for example, bringing food to the mouth) and joints in the lower limbs are for stability: maintaining the body’s small base­ a person would easily fall over if the muscles were not constantly moving the joints to adjust balance. Hinge joints​
(articulacions en bisagra) ● The elbow joint It allows the arm to bend (flex), or straighten (extend), as happens when doing “push ups” exercise on the ground or on a bench. The muscles wich flex the joint are on the front of the arm (biceps), and the muscles wich extend it are on the back (triceps). ● The knee joint This is the biggest and most complex joint. The tibia is prefixed on the femur so that the leg can be flexed or extended, as when a footballer bends the lower leg at the knee preparing to kick the ball (flexion) and then the extension is to strike the ball. Ball Joints (Articulacions pilota) ● The shoulder and hip joints These are called ball joints because the head of the long bone (the humerus in the arm or the femur in the leg) is formed like a ball. The hip and shoulder joints are very similar as the bones that connect are covered with cartilage and reinforced and held together with ligaments. Both joints can perform flexion, extension, adduction, abduction and rotation movement. How to work them: ­ If the angle of the joint is getting smaller then the movement is ​
flexion​
. ­ If the angle of the joint is getting bigger then the movement is ​
extension​
. ­ If the movement is taking away from the body then the movement is ​
adbuction. ­ If the movement is adding from the body then the movement is ​
adduction​
. ­ If the movement is around then the movement is ​
rotation​
.