[Fr. jointe, fr L. junctio, a joining]
The place where two or more bones meet. Some joints are fixed or immobile attachments of bones; other joints allow the bones to move along each other. A joint usually has a thin, smooth articular cartilage on each bony surface and is enclosed by a joint capsule of fibrous connective tissue. A joint is classified as immovable (synarthrodial), slightly movable (amphiarthrodial), or freely movable (diarthrodial). A synarthrodial joint is one in which the two bones are separated only by an intervening membrane, such as the cranial sutures. An amphiarthrodial joint is one having a fibrocartilaginous disk between the bony surfaces (symphysis), such as the symphysis pubis; or one with a ligament uniting the two bones (syndesmosis), such as the tibiofibular articulation. A diarthrodial joint is one in which the adjoining bone ends are covered with a thin cartilaginous sheet and joined by a joint capsule lined by a synovial membrane, which secretes synovial fluid.
SYN: arthrosis (1)
TYPES OF JOINTS
Joints are also grouped according to their motion: ball and socket (enarthrodial); hinge (ginglymoid); condyloid; pivot (trochoid); gliding (arthrodial); and saddle joint.
Joints can move in four ways: gliding, in which one bony surface glides on another without angular or rotatory movement; angulation, occurring only between long bones, increasing or decreasing the angle between the bones; circumduction, occurring in joints composed of the head of a bone and an articular cavity, the long bone describing a series of circles, the whole forming a cone; and rotation, in which a bone moves about a central axis without moving from this axis. Angular movement, if it occurs forward or backward, is called flexion or extension, respectively; away from the body, abduction; and toward the median plane of the body, adduction.
Because of their location and constant use, joints are prone to stress, injury, and inflammation. The main diseases affecting the joints are rheumatic fever, rheumatoid arthritis, osteoarthritis, and gout. Injuries comprise contusions, sprains, dislocations, and penetrating wounds.
A joint that is both ginglymoid and arthrodial.
Diarthrosis permitting a gliding motion.
SYN: gliding joint
A joint with two chief movement axes at right angles to each other.
A joint separated into two sections by interarticular cartilage.
Hemorrhage into joint space in hemophiliacs.
SYN: hemophilic joint
SEE: Budin joint
A joint with cartilage between the bones.
SEE: Charcot, Jean M.
SEE: Chopart, François
SEE: Clutton joint
A hinge joint permitting lateral motion.
SYN: spiral joint
A joint made up of several bones.
SEE: Ellipsoid joint.
A joint permitting all forms of angular movement except axial rotation.
The sound produced by forcible movement of a joint by contracting the muscles that contract or extend a joint, esp. the metacarpophalangeal joints. The cause is not known.
Either of the encapsulated, double synovial joints between the condylar processes of the mandible and the temporal bones of the cranium. The double synovial joints are separated by an articular disk and function as an upper gliding joint and a lower modified hinge or ginglymoid joint.
SYN: temporomandibular joint
A joint characterized by the presence of a cavity within the capsule separating the bones, permitting considerable freedom of movement.
Arthritis of the chronic villous type.
The hinge joint between the humerus and the ulna.
A joint with two axes of motion through the same bone.
SYN: condylar joint
Any of the zygapophyseal joints of the vertebral column between the articulating facets of each pair of vertebrae.
A false joint formation after a fracture.
Any of the joints connected by fibrous tissue.
A joint that is extremely relaxed, the distal portion of the limb being almost beyond the control of the will.
SEE: Arthrodial joint.
SEE: Bleeders' joint.
A synovial joint in which two bones flex and extend in only one plane, usually because side (collateral) ligaments limit the direction of motion, e.g., elbow joint.
A synovial ball-and-socket joint in which the head of the femur fits into the acetabulum of the hip bone. More than seven separate ligaments hold the joint together and restrict its movements.
Any of the articulations formed by the carpal bones in relation to one another.
A recurrent joint inflammation of unknown cause.
The joint formed by the femur, patella, and tibia.
A joint separating the navicular, lunate, and triangular bones from the distal row of carpal bones.
A slightly movable or freely movable joint, amphiarthrodial and diarthrodial, respectively.
A natural joint present in the body without surgical modification as opposed to a prosthetic joint.
A synovial joint between bone surfaces, in which only gliding movements are possible.
A technique for minimizing stress on joints, including proper body mechanics and the avoidance of continuous weight-bearing or deforming postures.
SEE: Saddle joint.
SEE: Pivot joint.
The articulation between the sacrum and the ilium of the hip bone. Joint movement is limited because of interlocking of the articular surfaces.
A joint in which the opposing surfaces are reciprocally concavoconvex.
SYN: receptive joint
The ball-and-socket joint between the head of the humerus and the glenoid cavity of the scapula.
A joint composed of two bones.
A multiaxial joint with spheroid surfaces.
SEE: Cochlear joint.
The joint space between the sternum and the medial extremity of the clavicle.
A joint with reduced mobility.
Any of the three articular surfaces on the inferior surface of the talus.
An articulation between two cranial or facial bones.
A joint in which the articulating surfaces are separated by synovial fluid.
SEE: joint for illus
A joint composed of three arthrodial joints, the bones of which articulate with the bases of the metatarsal bones.
SEE: Pivot joint.
The functional articulation of the distal ulna, articular disk, and triquetrum. The disk may subluxate following injury or with arthritis and block supination of the forearm.
A joint moving on a single axis.
A joint with a single cavity.