Articular System - Types and Characteristics of Joints

Vocabulary flashcards on joint classification, characteristics, types, stability factors, and innervation rules based on the Articular System lecture.

Joint

The point at which two or more bones make contact or articulate.

Fibrous Joints (Synarthroses)

Joints in which the bones are united by fibrous tissue and allow no movement.

Suture

A type of fibrous joint found only between the bones of the skull that permits limited movement until about 20 years of age, after which it becomes fixed.

Syndesmosis

A fibrous joint in which the intervening connective tissue is considerably greater in amount than in a suture, such as the inferior tibiofibular joint.

Gomphosis

An immovable fibrous joint where teeth articulate with their sockets in the maxillae or mandible, bound by the periodontal ligament.

Cartilaginous Joints (Amphiarthroses)

Joints in which the bones are united either by hyaline cartilage or by fibrocartilage.

Primary Cartilaginous Joint (Synchondrosis)

A temporary, immovable, and strong joint where bones are united by a plate of hyaline cartilage that is eventually replaced by bone.

Secondary Cartilaginous Joint (Symphysis)

A permanent joint located in the median plane where articular surfaces are covered by hyaline cartilage and united by fibrocartilage, allowing limited movement.

Synovial Joints (Diarthroses)

Freely moveable joints characterized by a cavity filled with synovial fluid, serving as the main type of joint found throughout the body.

Synovial Membrane

The tissue lining the inner surface of the joint capsule in a synovial joint that produces lubricating synovial fluid.

Uniaxial Joint

A joint that has one axis of rotation and one degree of freedom, such as hinge and pivot joints.

Biaxial Joint

A joint that has two axes of rotation and two degrees of freedom, such as ellipsoid and saddle joints.

Polyaxial Joint

A joint that has more than two axes of rotation and three or more degrees of freedom, such as ball-and-socket joints.

Plane Joint

A synovial joint with flat articular surfaces permitting gliding or slipping in any direction, or twisting of one bone on another.

Hinge Joint

A uniaxial synovial joint permitting movement in one transverse plane, allowing only flexion and extension.

Pivot Joint

A uniaxial synovial joint in which a cylindrical surface rotates within a ring of bone and fibrous tissue, allowing movement in one vertical plane.

Ellipsoidal Joint

A biaxial synovial joint featuring a convex oval surface articulating with an elliptical concave surface, permitting flexion, extension, adduction, and abduction.

Saddle Joint

A biaxial synovial joint where both articular surfaces are concavoconvex, shaped like a saddle.

Ball and Socket Joint

A polyaxial synovial joint where a spheroidal surface moves within a socket about three axes, permitting flexion, extension, adduction, abduction, rotation, and circumduction.

Intra-Articular Structures

Structures inside a synovial joint—including menisci, ligaments, intra-articular discs, pads of fat, and synovial folds—that assist in spreading synovial fluid for lubrication.

Factors of Joint Stability

The three components stabilizing synovial joints: bony factors (articular surface shape/fit), ligamentous factors (preventing excessive movement), and muscular factors (tone of surrounding muscles).

Hilton's Law

The principle stating that the nerves supplying a joint also supply the muscles moving that joint and the skin covering their distal attachments.