Movement at Joints

Header: Types of Joints

Joints are the locations where two or more bones meet, providing the necessary motion for our body.
There are different types of joints in the body, notably the ball-and-socket joint, the hinge joint, the pivot joint, and the saddle joint.
Ball-and-socket joints provide the greatest range of movement, allowing rotation and movement in all directions. Examples include the shoulder and hip joints.
Hinge joints, like those found in the knee and elbow, allow movement in one direction, similar to the opening and closing of a door.
Pivot joints allow rotational movement around a central point, such as the joint between the first and second vertebrae that enables the head to turn side to side.
The saddle joint, such as the one at the base of the thumb, allows movement in two directions, much like a saddle on a horse.

Header: Joint Movements

Movements at the joints include flexion, extension, abduction, adduction, rotation, and circumduction.
Flexion is the bending of a joint to decrease the angle between two bones, such as bending the elbow.
Extension is straightening a joint, or increasing the angle between two bones, such as straightening the arm.
Abduction is the movement of a bone away from the midline of the body, like lifting your arm sideways away from your body.
Adduction is the movement of a bone towards the midline of the body, like lowering your arm back down to your side.
Rotation is the spinning of a bone around its own axis, for example, twisting your neck to look over your shoulder.
Circumduction is the circular movement of a joint, combining abduction, adduction, extension, and flexion, like doing arm circles with your shoulder.

Header: Synovial Fluid and Cartilage

Movement can be smooth and frictionless at the joints due to the presence of lubricating substances like synovial fluid and protective materials like cartilage.
Synovial fluid, present within the synovial membrane of the joint capsule, serves to lubricate the articulating surfaces.
Cartilage covers the ends of each bone in a joint, providing a smooth, slippery surface that reduces friction and absorbs shock from the impact of activities such as running or jumping.

Having a good grasp of how these elements function in a healthy person is important for understanding the challenges and complications when joint disease or injury occurs, and how best to prevent and treat such issues in the context of physical education.