Joint Definition:
Where Two Bones Connect

Joint definition: The place where where two different bones meet and connect.  Often times, a joint allows the 2 bones to move.  An example of this are your knee joints, which allow the thigh and calf to move.  However, some joints do not allow the 2 bones to move at all, and an example of this would be the joints (called fibrous joints) found in your skull.  A fibrous joint connects different pieces of skull bones together without allowing the bones to move.

two different bones meet and connect

20160920 Joints definition types
(click to enlarge)

Besides the fibrous joints found in the skull, the four most commonly-found types of joints are:

  1. Pivot Joints: The best examples are the joints in the spine.  Pivot joints allow a little bit of rotation movements.
  2. Ball-and-Socket Joints: The best examples are your shoulder joints.  It is shaped like a ball-in-the-socket and allows a pretty wide angle of rotation movements.
  3. Saddle Joints: The best examples are your thumb joints.  They can move in most directions, but the movement is not as wide as ball-and-socket joints.
  4. Hinge Joints:  The best examples are your knee joints.  It allows a fair amount of movement in some directions, but it forbids movements in the opposite direction.  For example, in your knees’ example, they cannot bend upward.


Next Generation Science Standards:

MS-LS1-3 Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.

HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.

What Science Does this Comic Teach?

Unit: Anatomy

⇒Chapter: Immunology

⇒Topic: Joint: Definition

Additional Information


Bone is a type of connective tissue, and it consists of 4 different types of “bone cells” called: osteocyte cells, osteoblast cells, stem cells, and lining cells.

Fibrous Joint and Your Skull

Your round skull is made of different pieces of bones, which are connected together by special joints called “fibrous joints”.  These fibrous joints lock the bones in place, so they do not move.  This is why your round head cannot change its shape.


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