A joint is a point in the body where two bones meet. The joints in the human body are classified according to their range of movement. The three main types of joint are synarthroses, symphyses and diarthrosis.
Types of Joints
The three different types of movements a joint can make are, immovable (synarthroses), slightly movable (symphyses) or freely movable (diarthrosis).
Synarthroses joints, or fibrous joints, are rigid and immovable such as the joints in the skull. The bones in the skull are jointed right next to each other. They are held together by fibrous connective tissue or sutures.
Symphyses, also known as amphiathroses, joints are slightly movable. A fibrous cartilage connects this type of joint. Examples of these types of joints are the pelvis, ribs and vertebrae. Each joint has a small cartilage pad, which acts as a shock absorber and allows a slight movement back and forth.
The body is mostly made up of diarthrosis or synovial joints, which move freely in many directions. These joints are characterized by cartilage and synovial fluid so they can move more freely. There are six different types of diarthrosis joints: hinge, pivot, ball and socket, saddle, condyloid and gliding.
Types of Fully Moveable Joints
The hinge joints, such as elbow, jaw, knees and finger knuckles, allow forward flexion movement and extension back to its straightened position.
A pivot joint, such as the neck and elbow, can pivot on their axis point, turning side to side.
Ball and socket joints, such as hips and shoulders, allow a wide arrange of movement. The ball at the end of the bone fits into a cup or socket of the other bone it is connected to. The bones are cushioned by cartilage and synovial fluid and can move in any direction.
The only saddle joint in the body is the thumb. The saddle joint allows forward, backward, side to side and elliptical movement.
Condyloid joints are all the joints where the fingers meet the hand. The joint allows an elliptical and side-to-side movement.
A gliding joint, such as the wrist and ankle, can glide over the other bone, bend forward and back or move circularly.