Joints and Articulations: every key term you need (+ practice quiz)
25 flashcard terms for Anatomy & Physiology I Topic 6, written to match the course framework. Study them here, then drill them as interactive flashcards, or test yourself with the 15-question quiz — free, no account needed.
Any site where two bones, or a bone and a tooth or cartilage, meet. Joints are classified by the material binding them and by how much movement they allow, and the two schemes largely overlap.
Fibrous joint
A joint in which bones are united by dense fibrous connective tissue with no cavity between them. Most are immovable or nearly so, and the length of the connecting fibers sets the permitted range.
Suture
An interlocking fibrous joint between skull bones bound by very short connective tissue fibers. Sutures allow slight growth in youth and typically ossify in adulthood, fusing the bones into a single unit.
Syndesmosis
A fibrous joint in which bones are connected by a ligament or interosseous membrane. The distal tibiofibular connection permits slight give, while the radioulnar membrane permits appreciable rotation.
Gomphosis
The peg-in-socket fibrous joint anchoring a tooth in its bony alveolus. The short periodontal ligament holds the tooth firmly while allowing minute movement that cushions chewing forces.
Cartilaginous joint
A joint in which bones are joined by cartilage without a cavity. Synchondroses use hyaline cartilage and are immobile, while symphyses use fibrocartilage and permit limited compressible movement.
Symphysis
A cartilaginous joint where a pad of fibrocartilage joins bones faced with hyaline cartilage. The pubic symphysis and intervertebral discs absorb shock while allowing small amounts of motion.
Synovial joint
A freely movable joint in which bones are separated by a fluid-filled cavity. All share articular cartilage, a two-layered capsule, synovial fluid, reinforcing ligaments and a rich nerve and blood supply.
Articular cartilage
The glassy hyaline covering on the bone ends within a synovial joint. It spreads load, provides a low-friction surface, and lacks blood vessels, which is why its injuries heal slowly and incompletely.
Articular capsule
The sleeve enclosing a synovial cavity, made of a tough outer fibrous layer continuous with the periosteum and an inner synovial membrane of loose tissue that produces the joint fluid.
Synovial fluid
A viscous filtrate of blood enriched with hyaluronan and lubricating glycoprotein. It lubricates and nourishes the cartilage and is squeezed in and out of it as the joint is loaded and unloaded.
Bursa
A flattened fibrous sac lined with synovial membrane and containing a thin film of fluid, placed where ligaments, muscles, skin or tendons rub over bone. Inflammation of one causes localized painful swelling.
Tendon sheath
An elongated bursa wrapped around a tendon subject to friction, most often where tendons crowd through the confined spaces of the wrist and ankle.
Meniscus
A wedge of fibrocartilage set between articulating surfaces to improve fit, distribute load and add stability. The knee has two, and tears are common because the inner region is poorly vascularized.
Hinge joint
A uniaxial synovial joint in which a cylindrical surface fits a trough, permitting flexion and extension in a single plane. The elbow and the interphalangeal joints work this way.
Pivot joint
A uniaxial synovial joint in which a rounded end rotates within a ring of bone and ligament. The joint between the first two cervical vertebrae lets the head rotate to signal no.
Ball and socket joint
A multiaxial synovial joint with a spherical head in a cup-shaped socket, permitting motion in all three planes plus rotation. The shoulder and hip are the only examples in the body.
Condylar joint
A biaxial synovial joint in which an oval surface fits a matching depression, allowing flexion, extension and side-to-side movement but no free rotation. The knuckles are the standard example.
Saddle joint
A biaxial joint whose two surfaces are each concave in one direction and convex in the other, fitting together like a rider on a saddle. The thumb carpometacarpal joint gives opposition.
Plane joint
A synovial joint with flat or slightly curved surfaces permitting short gliding movements. Intercarpal, intertarsal and vertebral facet joints belong to this nonaxial group.
Flexion and extension
Paired angular movements in the sagittal plane. Flexion decreases the angle between articulating bones and usually moves a part anteriorly, while extension increases the angle and reverses that motion.
Abduction and adduction
Paired frontal plane movements relative to the midline. Abduction moves a limb away from the body midline, adduction returns it toward the midline; for digits the reference line runs through the middle.
Circumduction
Movement in which the distal end of a limb traces a circle while the proximal end stays fixed, producing a cone. It combines flexion, abduction, extension and adduction in sequence.
Supination and pronation
Rotational movements of the forearm. Supination turns the palm anteriorly with radius and ulna parallel; pronation turns the palm posteriorly and crosses the radius over the ulna.
Osteoarthritis
The common degenerative joint disorder in which articular cartilage softens and erodes faster than it is replaced, exposing bone, provoking bony spurs and producing stiffness and grating on movement.