Joints

     Everything that we do is possible because of joints we have in our skeleton. A joint is any place in which two or more bones join together. These bones don't hold in place magically, instead all the bones are held tight by a tough band of tissue named ligament. Some bones have a thin layer of cartilage in between them therefore preventing them to rub against each other.

     A common joint problem is arthritis. The word arthritis isn't specifically a disease, but is a term used to describe more than 100 different diseases in the joints. Some of the symptoms of arthritis are but are not limited to: pain, stiffness, and swelling of the joints.

     There are two different joints in our body. The immovable joints and the movable joints.

Immovable Joints

• An immovable joint is a joint which permits small or no movement at all.
• An example is the joints in our skull and pelvis.

Movable Joints

    Movable joints allow movement in our body. The four types of movable joints are pivot, ball-and-socket, hinge, and gliding.

• A pivot joint, as shown in the image in the right, is when one bone rotates in a ring of another bone that does no movement. For example, turning our heads.

• A ball-and-socket produces a wider range of motion possible. It can move in almost 360 degrees. As show in the image to the right, our shoulder is an example of this joint because it can move in many directions.

 

• A hinge joint is a joint that allows a back and forth movement. An example of these movements are elbow, knee, and finger joints. As shown in the image to the right, limited movement is allowed like in a real life elbow.

• Another type of joint is a gliding joint, which one bone slides over another part of another bone. This is the type of joint that is mostly used in our bodies. This joints are kid of the same like hinge joints but the difference is that the bones aren't beside each other, the bones are moving on top of each other.

Moving Smoothly

     Lets say you are writing in a chalk board with a chalk. Eventually, the chalk wears away. Fortunately for our bones, they have cartilages. These cartilages help movement in the joint easier.  If the joints didn't exist our bones would wear away just like chalk does when being used.