What are hinge joints and pivot joints?

Answer 1

A hinge is a type of joint the largest one is found in the knee. Another good example is a hinge on your door, which attaches the door to the door frame, but also allows the door to swing open or closed.

Answer 2

Hinge joints allow movement in one direction, as seen in the knees and elbows and fingers.
FUNCTION: The purpose of joints is to provide movement for the body. Different types of joints move in different ways. The hinge joint is shaped to restrict movement to one plane. It has strong collateral ligaments that aid and restrict movement. The ends of the bones are covered with tough cartilage and are lined with the synovial membrane.
Each joint contains a small amount of synovial fluid which lubricates it. Synovial fluid provides protection for the hinge joint and allows for its stress-free movement.
The hinge joint provides a connection that allows articular surfaces to be closely molded together. This molding together permits extensive motion in one plane. The joint has stabilizing ligaments that limit the directions and extent to which the bones can be moved. The hinge joint moves back and forth with some rotation allowed.


-->*Pivot joints allow a rotating or twisting motion, like that of the head moving from side to side.The rotation of the skull is made possible by a pivot joint.
FUNCTION: A pivot joint allows movement in one plane, such as rotation about an axis. Pivot joints, for example, permit one, after bending the elbow, to turn the palm of one's hand upward or downward by rotating the forearm. The two bones of the forearm (the ulna and the radius) twist around each other using a pivot joint.
STRUCTURE: Pivot joints hold the two bones of the forearm together. That is, a pivot joint, located near the elbow, joins the bones of the forearm (called the ulna and the radius) to each other. These two bones are also joined to each other near the wrist by another pivot joint. A different pivot joint, located at the base of the skull, joins the first vertebra of the spine to the second vertebra and thus permits the head to rotate (since the first vertebra is joined to the skull).
If the bony surfaces of two bones that meet at a joint actually touched each other, then motion would cause friction, which would soon produce wear and tear on the touching ends of the bones. An engineer designing a mechanical counterpart would arrange for lubricating oil to prevent such wear and tear and facilitate smooth movement between the two metal "bones." A joint thus holds bones together (it is called a "joint" because it "joins" them) but also keeps them slightly separated to prevent their damaging each other in motion.