Joint Classifications, Structure, and Function

Vocabulary flashcards covering the anatomical and physiological classifications of joints, joint components, synovial accessory structures, and the six structural types of synovial joints.

Structural Classification of Joints

An anatomical classification based on the material binding the bones together, dividing joints into fibrous, cartilaginous, and synovial categories.

Functional Classification of Joints

A physiological classification based on the degree of movement permitted at a joint, designated into synarthrosis, amphiarthrosis, and diarthrosis.

Fibrous Joint

A joint held together by dense irregular connective tissue fibers (mostly collagen) that lacks a synovial cavity and cartilage.

Cartilaginous Joint

A joint held together by a solid piece or bar of cartilage, lacking a synovial cavity.

Synovial Joint

A freely movable joint held together by ligaments, containing a synovial cavity filled with synovial fluid between articulating bones.

Synarthrosis

An immovable joint where the force generated by muscular contraction is insufficient to produce movement.

Amphiarthrosis

A slightly movable joint, typically represented by cartilaginous articulations such as the pubic symphysis.

Diarthrosis

A freely and fully movable joint, functionally corresponding to synovial joints found predominantly in the appendicular skeleton.

Sutures of the Skull

Fibrous joints where skull bones are held firmly together by dense irregular collagen fibers rather than fused by calcium.

Teeth Joints

Fibrous joints where the teeth are anchored into the mandible and maxilla by dense irregular connective tissue fibers.

Epiphyseal Growth Plate

A temporary cartilaginous joint composed of hyaline cartilage uniting the epiphysis and diaphysis in a growing bone, classified functionally as a synarthrosis.

Synovial Cavity

A space between articulating bones enclosed by a two-layered capsule consisting of an outer fibrous capsule and an inner synovial membrane.

Synovial Membrane

The inner layer of the joint capsule composed of connective tissue and synoviocytes that secrete synovial fluid.

Synovial Fluid

A fluid that lubricates the joint to reduce friction and circulates oxygen and nutrients to avascular articular cartilage while removing metabolic wastes.

Cavitation

The collapse of accumulated dissolved gas bubbles in synovial fluid caused by movement-induced pressure changes, resulting in a popping sound.

Stability-Mobility Relationship

An inverse mechanical relationship where an increase in a joint's mobility causes a decrease in its stability, and vice versa.

Proprioceptors

Sensory receptors located in the joint capsule that detect joint angle, position, and applied force to relay positional awareness to the brain.

Ligaments

Bands of dense regular connective tissue with parallel-running fibers that attach bone to bone and resist separation.

Bursa

A fluid-filled sac situated around highly mobile joints that acts as a cushion and reduces friction between moving structures.

Bursitis

Inflammation of a bursa that triggers pain to mechanically limit joint motion and prevent further damage.

Menisci

Fibrocartilaginous discs in the knee joint that absorb shock and prevent excessive wear on the articular surfaces beyond what hyaline cartilage can withstand.

Planar Joint

A synovial joint with flat or slightly curved articulating surfaces allowing biaxial or triaxial gliding movements, such as the intertarsal joints between the navicular and cuneiforms.

Hinge Joint

A uniaxial synovial joint in which a convex surface fits into a concave surface to permit motion in one plane, such as the trochlea and trochlear notch at the elbow.

Pivot Joint

A uniaxial synovial joint where a rounded bone surface rotates within a ring formed by another bone and a ligament, such as the articulation between the radius and ulna.

Condyloid Joint

A biaxial synovial joint featuring an oval-shaped convex projection that fits into an elliptical concave depression, such as the wrist joint between the radius, scaphoid, and lunate.

Saddle Joint

A biaxial synovial joint where one articulating surface is saddle-shaped and the other fits across it, exemplified by the joint between the trapezium and the first metacarpal of the thumb.

Ball and Socket Joint

A triaxial synovial joint consisting of a rounded, ball-like surface articulating within a cup-like depression, found in the shoulder and hip joints.