Arthrology: Joints and Articulations

Vocabulary practice flashcards covering joint classifications (functional and structural), synovial joint features, joint movements, and knee pathology from the Arthrology lecture.

Joint (Articulation)

The site where two or more bones meet, functioning to provide binding and mobility to the skeleton.

Synarthrosis

A functional classification of a joint denoting an immovable joint.

Amphiarthrosis

A functional classification of a joint denoting a slightly movable joint.

Diarthrosis

A functional classification of a joint denoting a freely movable joint.

Fibrous Joint

A structural category of joint where bones are joined by dense fibrous connective tissue without a joint cavity; most are synarthrotic (immovable).

Suture

A fibrous joint found exclusively in the skull, held together by very short interconnecting fibers with interlocking bone edges that ossify and fuse later in life.

Syndesmosis

A fibrous joint held together by a ligament or cord of fibrous tissue of variable length, such as the inferior tibiofibular joint.

Gomphosis

A 'peg-in-socket' fibrous joint where a tooth is held in its alveolar socket by the periodontal ligament.

Cartilaginous Joint

A structural class of joint where articulating bones are united by cartilage without a joint cavity, exhibiting limited mobility.

Synchondrosis

A cartilaginous joint united by hyaline cartilage, such as an epiphyseal plate or the joint between the first rib and the sternum.

Symphysis

A strong, amphiarthrotic cartilaginous joint where fibrocartilage is sandwiched between hyaline cartilage, such as intervertebral discs and the pubic symphysis.

Synovial Joint

A diarthrotic joint characterized by articulating bones separated by a fluid-filled joint cavity; includes nearly all limb joints.

Muscle Tone (Joint Stability)

The most important of three factors stabilizing synovial joints, functioning to keep tendons taut across the joint.

Synovial Fluid

A viscous, slippery filtrate of plasma and hyaluronic acid that lubricates joint surfaces, nourishes cartilage, and contains phagocytic cells.

Articular Capsule

A two-layered joint envelope enclosing a synovial cavity, comprising an external fibrous layer of dense irregular connective tissue and an inner synovial membrane of loose connective tissue.

Bursa

A flattened fibrous sac lined with synovial membrane and filled with synovial fluid that acts like a 'ball bearing' to reduce friction where ligaments, muscles, skin, tendons, or bones rub together.

Tendon Sheath

An elongated bursa wrapped completely around a tendon subjected to friction.

Articular Disc (Meniscus)

A fibrocartilage pad that separates articular surfaces within a synovial joint to improve bone fit, stabilize the joint, and reduce wear and tear.

Plane Joint

A synovial joint with flat articular surfaces permitting nonaxial gliding movements, such as intercarpal and intertarsal joints.

Hinge Joint

A uniaxial synovial joint formed by a cylindrical bone projection fitting into a trough, permitting flexion and extension (e.g., elbow and interphalangeal joints).

Pivot Joint

A uniaxial synovial joint in which a rounded bone axle rotates within a sleeve composed of bone and ligament (e.g., proximal radioulnar and atlantoaxial joints).

Condylar Joint

A biaxial synovial joint featuring oval articular surfaces that allow flexion, extension, abduction, and adduction (e.g., metacarpophalangeal and wrist joints).

Saddle Joint

A biaxial synovial joint where both articulating surfaces have concave and convex areas, allowing opposition and angular movements (e.g., carpometacarpal joint of the thumb).

Ball-and-Socket Joint

A multiaxial synovial joint featuring a spherical head articulating with a cup-like socket, permitting movements in all axes including circumduction and rotation (e.g., shoulder and hip joints).

Flexion

An angular movement that decreases the angle between two bones, usually occurring in the sagittal plane.

Extension

An angular movement that increases the angle between two bones, usually occurring in the sagittal plane.

Abduction

An angular movement that moves a limb away from the body midline in the frontal plane.

Adduction

An angular movement that moves a limb toward the body midline in the frontal plane.

Circumduction

An angular movement of a limb or finger describing a cone in space.

Supination and Pronation

Rotational movements of the forearm; supination positions the radius parallel to the ulna (palm facing anteriorly), while pronation rotates the radius over the ulna (palm facing posteriorly).

Opposition

A saddle joint movement of the carpometacarpal joint of digit I enabling the thumb to touch the fingertips of the same hand.

Muscle Origin

The skeletal attachment site of a muscle fixed to the immovable (or less movable) bone.

Muscle Insertion

The skeletal attachment site of a muscle fixed to the movable bone, which is pulled toward the origin during contraction.

Unhappy Triad

A severe knee injury typically caused by a lateral blow to an extended knee, resulting in tearing of the tibial collateral ligament, medial meniscus, and anterior cruciate ligament (ACL).