Synovial Joint

Synovial Joints: Synovial joints are the most common joint type in the human body. They have a unique structure that includes a joint capsule, synovial fluid, articular cartilage covering bone surfaces, articular discs, intricate ligament systems to support motion, and often bursae. This unique structure allows for more motion than fibrous joints (also known as immovable joints) and cartilaginous joints (partly moveable joints).

Synovial Joint Types:

• A hinge joint (ginglymus joint) is a joint in which the articular surfaces are shaped so that motion is permitted primarily in one plane. Usually, these joints have a structure resembling a notched surface that fits in a groove. The largest hinge joint in the body is the knee.
• The ball and socket joint (or spheroidal joint) is a joint in which the ball-shaped surface of one bone fits a cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes with one common center. This enables the joint to move in all planes. An example of a ball and socket joint is the hip.
• A pivot joint (trochoid joint, rotary joint, lateral Ginglymus) is a type of diarthrosis . In pivot joints, the axis of a convex joint surface rotates or "spins" along a perpendicular axis of another bone. These joints allow for only rotary movements. An example of a pivot joint is the atlantoaxial joint (C1 and C2).
• A gliding joint (arthrodial joint or plane joint) is a synovial joint that allows only gliding movement. The surfaces of the bones are flat or almost flat and only permit sliding or gliding movements in the plane of the joint surfaces. An example of gliding joints is the facet joints of the spine.
• In a saddle joint (sellar joint), the opposing surfaces are reciprocally concave-convex, similar to the way rounded "U" shapes would fit into one another. This allows motion in 2 planes, similar to how a horseback rider can move in a saddle. An example of a saddle joint is the carpometacarpal joint at the base of the thumb.
• A condyloid joint (also called a condylar, ellipsoidal, or bicondylar joint) is an ovoid articular surface that is received into an elliptical cavity. These joints permit movement in 2 planes. An example of a condyloid joint is the wrist.