Joints and Articulations

Comprehensive vocabulary flashcards covering structural and functional classifications of joints, synovial joint anatomy, body movements, and joint disorders.

Joints (Articulations)

Sites where two or more bones meet, serving to give the skeleton mobility and hold it together.

Synarthroses

Immovable joints, classified according to the movement they allow.

Amphiarthroses

Slightly movable joints, classified according to the movement they allow.

Diarthroses

Freely movable joints, classified according to the movement they allow.

Fibrous Joints

Joints where bones are joined by dense fibrous connective tissue with no joint cavity; most are immovable.

Sutures

Rigid, interlocking fibrous joints found only in the skull that contain short connective tissue fibers allowing for expansion during youth.

Synostoses

Closed, completely ossified and fused sutures that join the skull into one unit in middle age.

Syndesmoses

Fibrous joints where bones are connected exclusively by ligaments or bands of fibrous tissue, with movement varying according to fiber length.

Gomphoses

Peg-in-socket fibrous joints where teeth are secured in their alveolar sockets by the periodontal ligament.

Cartilaginous Joints

Joints in which articulating bones are united by cartilage, lacking a joint cavity and not highly movable.

Synchondroses

Cartilaginous joints united by a bar or plate of hyaline cartilage; almost all are synarthrotic (immovable).

Symphyses

Strong, amphiarthrotic cartilaginous joints where bones are united by fibrocartilage, such as the pubic symphysis and intervertebral joints.

Synovial Joints

Freely movable (diarthrotic) joints in which articulating bones are separated by a fluid-filled joint cavity.

Articular Cartilage

Hyaline cartilage covering the opposing bone surfaces in synovial joints to prevent crushing of bone ends.

Joint (Synovial) Cavity

A small, fluid-filled potential space that is unique to synovial joints.

Articular Capsule

A two-layer capsule enclosing the joint cavity, composed of an external fibrous layer of dense irregular connective tissue and an inner synovial membrane of loose connective tissue.

Synovial Fluid

A slippery filtrate of plasma and hyaluronic acid that lubricates and nourishes articular cartilage and contains phagocytic cells to clear debris.

Articular Discs (Menisci)

Pads of fibrocartilage that separate articular surfaces to improve bone end fit, stabilize the joint, and reduce wear and tear.

Bursae

Flattened fibrous sacs filled with synovial fluid that act as lubricating bearings to reduce friction where adjacent structures rub together.

Tendon Sheaths

Elongated bursae wrapped completely around tendons subjected to friction.

Gliding Movements

Joint motions where one flat bone surface slips or glides over another without significant angulation or rotation, as seen in intercarpal joints.

Flexion

An angular movement along the sagittal plane that decreases the angle of the joint.

Extension

An angular movement along the sagittal plane that increases the angle of the joint.

Hyperextension

The extension of a joint beyond anatomical position.

Abduction

Movement along the frontal plane away from the midline of the body.

Adduction

Movement along the frontal plane toward the midline of the body.

Circumduction

Movement of a limb in a circular manner such that it describes a cone in space; involves flexion, abduction, extension, and adduction.

Rotation

The turning of a bone around its own longitudinal axis, directed either toward the midline (medial) or away from it (lateral).

Supination

Rotation of the forearm so that the palm faces anteriorly and the radius and ulna lie parallel to each other.

Pronation

Rotation of the forearm so that the palm faces posteriorly and the radius rotates over the ulna.

Dorsiflexion

Movement that bends the foot superiorly toward the shin.

Plantar Flexion

Movement of the foot that points the toes inferiorly (downward).

Inversion

Special movement of the foot that turns the sole medially.

Eversion

Special movement of the foot that turns the sole laterally.

Protraction

Nonangular movement in an anterior direction in a lateral plane, such as jutting the jaw forward.

Retraction

Nonangular movement in a posterior direction in a lateral plane, such as pulling the jaw backward toward the neck.

Elevation

Lifting a body part superiorly, such as closing the jaw or shrugging the shoulders.

Depression

Moving an elevated body part inferiorly, such as opening the mouth.

Opposition

Saddle joint movement of the thumb that enables touching the tips of other fingers on the same hand for grasping.

Sprain

A joint injury that occurs when reinforcing ligaments are stretched or torn.

Dislocation (Luxation)

A joint injury in which bones are forced completely out of normal alignment.

Subluxation

The partial dislocation of a joint.

Bursitis

Inflammation of a bursa, typically caused by a blow or repetitive friction.

Tendonitis

Inflammation of tendon sheaths, typically caused by overuse.

Osteoarthritis (OA)

A chronic, degenerative wear-and-tear arthritis in which articular cartilage is broken down faster than it is replaced, often forming bone spurs (osteophytes).

Crepitus

A crunching or grating sound made by roughened articular surfaces rubbing together in stiff joints.

Rheumatoid Arthritis (RA)

A chronic, inflammatory, autoimmune disease of unknown cause where the immune system attacks joint tissues, leading to bilateral pain, swelling, and deformity.

Pannus

An abnormal, thickened synovial tissue that develops in rheumatoid arthritis and clings to and erodes articular cartilage.

Ankylosis

The abnormal stiffening and fusion of articulating bone ends by scar tissue in severe rheumatoid arthritis.

Gouty Arthritis

Inflammatory arthritis caused by the deposition of needle-shaped uric acid crystals in joints and soft tissues, commonly at the base of the big toe.

Lyme Disease

An inflammatory condition caused by bacteria transmitted by tick bites, characterized by a rash, flu-like symptoms, and potential chronic joint pain.