Where Are The 4 Types Of Joints On The Human Body?

A joint is the region where two or more bones make contact, providing mechanical support, and allowing movement in some cases. Joints are classified by the way bones are connected together, and also by the degree of movement between the bones. The four primary types of joint in the human body are hinge, ball and socket, pivot and gliding.

Joint Categories

Joints in the human body are considered fibrous, cartilaginous or synovial. Fibrous joints are connected by dense connective tissue, composed primarily of collagen. Cartilaginous joints are connected entirely by cartilage tissue, and synovial joints are composed of bone coated with a fluid-secreting membrane, which reduces friction in moving joints, according to "Gray's Anatomy."

Hinge

Movement in a hinge joint is permitted in only one single plane of action like the opening and closing of a door, and the two moving bones are connected with incredibly strong ligaments. Examples include the elbow, the joints between the fingers, and the knee, which is the largest hinge joint in the human body, according to the website Theodora.

Ball and Socket

The rounded or ball-shaped surface of one bone fits into the concave or cup-shaped depression of another bone to form a synovial joint, which allows 360-degree movement. Examples of ball and socket joints include the hip, where the ball-shaped head of the femur fits into the cup-like cavity of the pelvis, according to the Hip and Knee Institute.

Pivot

Turning of pivot joints usually occurs in a half circle, facilitated by the rotation of one bone around another. A pivot joint is formed by the meeting of two bones, one being a bony cylinder, and the other a ring-like structure constructed of bone and ligament. One example of a pivot joint is at the base of the skull, joining the first vertebra of the spine to the second vertebra, allowing the head to rotate, because the first vertebra is joined to the skull. Another example is the ulna, and radius bones in the forearm, according to an article published in November 2005 in the "Encyclopedia of Nursing and Allied Health."

Gliding

When the bony surfaces that hold a synovial joint together are flat or only slightly rounded, the joint is referred to as gliding. A gliding joint permits a wide range of motion, facilitated by the sliding of one bone past another. The vertebrae of the spine and the eight small bones that form the wrist are examples of gliding joints, according to an article published in January 2001 in the "Encyclopedia of Nursing and Allied Health."