CogKnoSys

Knowledge you can walk. Read the idea below, then step up to the general, across to peers or down to the specific.

Physical

Joint Types

Joint types are the different ways bones meet, from fixed skull joints to freely moving knees and shoulders.

Learn, discuss, create, buy or invest

The idea

A joint is a place where two bones, or other hard parts of the body, connect. Joints link the skeleton into one working whole. They are built to allow different amounts and kinds of movement. Scientists sort joints in two ways: by how they are built and by how much they move.

By structure, there are three main types. Fibrous joints are held together by tough connective tissue and barely move. The sutures between the bones of the skull are fibrous joints that move very little, which protects the brain. Even the joint that holds a tooth in the jawbone is a fibrous joint, called a gomphosis. Cartilaginous joints are joined by cartilage and allow a little movement, like the joints between the bones of the spine. Synovial joints have a fluid-filled space between the bones and move freely.

Synovial joints such as the knee, elbow and shoulder are self-lubricating and almost frictionless. They can carry heavy loads while still making smooth, precise movements. Hinge joints, like the elbow, bend back and forth, while ball-and-socket joints, like the shoulder, can swing in many directions. Joints can wear down or become inflamed in diseases such as osteoarthritis, rheumatoid arthritis and gout.

Check yourself

Question 1 of 3

What is the joint between a tooth and the jawbone called?

Pick one. The first pick counts.

Composition

what it's made of

  • Fibrous joints — Bones joined by tough tissue that allows little or no movement, such as the skull sutures.
  • Cartilaginous joints — Bones joined by cartilage that allows slight movement, as in the spine.
  • Synovial joints — Freely moving joints with a lubricated space between the bones, such as the knee.
  • Cartilage — Smooth tissue that covers the ends of bones; its breakdown causes osteoarthritis.
  • Ligaments — Strong bands of tissue that tie bones together and keep joints stable.

Connection

how it relates

Under Skeletal System

Related

  1. Muscle Contractionstrength 70 of 100

    Muscles contract and pull on bones, and joints are the points where that pull becomes movement.

  2. Frictionstrength 60 of 100

    Joints such as the knee are almost frictionless, so the bones glide past each other with little wear.

  3. Skeletal Musclestrength 50 of 100

    Skeletal muscles cross joints and attach to the bones on each side, so a joint moves only when they pull.

Change

how and why it evolves

Past
Early anatomists first described joints by studying skeletons, and later scientists sorted them by structure and by how much they move.
Now
Today joint problems are treated with physical therapy, medicine, lifestyle changes and, in severe cases, surgery.
Next
As more people live into old age, treatments for worn joints, including artificial replacement joints, will probably keep improving.

Knowledge you can walk. Read the idea, then step up, across or down.

Joint Types

Joint types are the different ways bones meet, from fixed skull joints to freely moving knees and shoulders.

Learn, discuss, create, buy or invest

The idea

A joint is a place where two bones, or other hard parts of the body, connect. Joints link the skeleton into one working whole. They are built to allow different amounts and kinds of movement. Scientists sort joints in two ways: by how they are built and by how much they move.

By structure, there are three main types. Fibrous joints are held together by tough connective tissue and barely move. The sutures between the bones of the skull are fibrous joints that move very little, which protects the brain. Even the joint that holds a tooth in the jawbone is a fibrous joint, called a gomphosis. Cartilaginous joints are joined by cartilage and allow a little movement, like the joints between the bones of the spine. Synovial joints have a fluid-filled space between the bones and move freely.

Synovial joints such as the knee, elbow and shoulder are self-lubricating and almost frictionless. They can carry heavy loads while still making smooth, precise movements. Hinge joints, like the elbow, bend back and forth, while ball-and-socket joints, like the shoulder, can swing in many directions. Joints can wear down or become inflamed in diseases such as osteoarthritis, rheumatoid arthritis and gout.

Check yourself

3 quick questions, instant feedback.