Joint Facts

Body joints are places where bones meet.
The skull is not one bone, but 22 separate bones bound tightly together with fibers so that they cannot move.
Most body joints (apart from fixed joints like the skull’s fibrous joints) let bones move, but different kinds of joint let them move in different ways.
Hinge joints, such as the elbow, let the bones swing to and fro in two directions like door hinges do.
In ball-and-socket joints, such as the shoulder and hip, the rounded end of one bone sits in the cup shaped socket of the other, and can move in almost any direction.
Swivel joints turn like a wheel on an axle. Your head can swivel to the left or to the right on your spine.
Saddle joints such as those-in the thumb have the bones interlocking like two saddles. These joints allow great mobility with considerable strength.
The relatively inflexible joints between the bones (vertebrae) of the spine are cushioned by pads of cartilage.
Synovial joints are flexible joints such as the hip-joint, lubricated with oily ‘synovial fluid’ and cushioned by cartilage.

This entry is filed under Interesting Facts.