Joints and their movement Lesson Three Joints and their movement

Types of joint How joints work Lesson Objective (s) At the end of this you will have gained a better understanding of: Types of joint How joints work

What Are the Joints and What Do They Do? Joints allow our bodies to move in many ways. There are three types of joints Immovable, or fibrous, joints Partially movable, or cartilaginous Freely movable, or synovial

Immovable, or fibrous, joints Joints are classified by their range of movement. Immovable, or fibrous, joints don't move. The dome of the skull, for example, is made of bony plates, which must be immovable to protect the brain. Between the edges of these plates are links, or joints, of fibrous tissue. Fibrous joints also hold the teeth in the jawbone.

Partially movable, or cartilaginous Partially movable, or cartilaginous (pronounced: kar-tuh-lah-juh-nus), joints move a little. They are linked by cartilage, as in the spine. Each of the vertebrae in the spine moves in relation to the one above and below it, and together these movements give the spine its flexibility.

Freely movable, or synovial Freely movable, or synovial (pronounced: sih-no-vee-ul), joints move in many directions. The main joints of the body — found at the hip, shoulders, elbows, knees, wrists, and ankles — are freely movable. They are filled with synovial fluid, which acts as a lubricant to help the joints move easily. There are three kinds of freely movable joints that play a big part in voluntary movement:

1. Sliding Joint The sliding joint (sliding or plane joint) is found in the vertebral column and allows small sliding movements. The vertebrae have pads of cartilage between them, and the bones slide over these pads. This is what makes the backbone so flexible.

2. Saddle Joint A saddle joint allows movement back and forth and up and down, but does not allow for rotation like a ball and socket joint

3. Ball and Socket Joint The ball-and-socket joint is found in the hip-bone and the shoulder and allows the most movement of all the joints. One bone (like the femur my student found) has a ball-like knob at the end of it, and the knob fits into a cup-like space on the other side. The ball-and-socket joint is what allows baseball pitchers to throw a ball with such tremendous speed

4. Pivot Joint The pivot joint allows movement turning from side to side, and your head is attached to your vertebral column with this joint. A hole in one bone fits over a pointed part of the other bone, so that one bone can turn on top of the other

5. Hinge Joint The hinge joint allows bones to move back and forth, and is found in your elbow and knee. It allows bones to move like a hinge in a door.

6. Condyloid (ellipsoid) joints Condyloid (ellipsoid) joints such as the knee. When the knee is extended there is no rotation, when it is flexed some rotation is possible. A condyloid joint is where two bones fit together with an odd shape (e.g. an ellipse), and one bone is concave, the other convex.

Revision

Joint classification – 3 types fibrous - bones are connected by fibrous connective tissue for example the skull and teeth. cartilaginous - bones are connected by cartilage for example the ribs, sternum and spine. synovial - there is a space (synovial cavity) between the articulating bones, these can be placed into six types.

Synovial joints Ball & Socket Condyloid Saddle Hinge Pivot