Articular System and Joints Lecture Notes

Vocabulary flashcards covering the articular system, types of cartilage, classifications of joints (fibrous, cartilaginous, and synovial), and accessory joint structures based on the University of Melbourne anatomy lecture.

Articular system

A system made up of joints, associated ligaments, and accessory structures.

Joint (Articulation)

A point of contact between two bones, bones and cartilage, or between bone and teeth.

Cartilage

A resilient, semirigid connective tissue located in parts of the skeleton where flexibility is required; it is nourished via diffusion as it lacks blood vessels, lymph, or nerves.

Hyaline cartilage

The most common type of cartilage that covers bony articular surfaces and serves as a model for the early fetal skeleton.

Elastic cartilage

A flexible cartilage containing bundles of elastic fibres, forming discrete structures in the external ear, auditory tube, and parts of the larynx.

Fibrocartilage

A mix of fibrous tissue and hyaline cartilage containing substantial amounts of collagen; it forms specialised structures like the disc, meniscus, or labrum and can withstand prolonged pressure.

Synovial joint

A moveable joint type where bones are united by a joint or articular cavity and separated by a fluid-filled cavity.

Fibrous joint

A solid joint with minimal movement where bones are united by fibrous tissue; the degree of movement depends on the length of the fibres.

Cartilaginous joint

A solid joint where bones are united by hyaline or fibrocartilage to provide strength and shock absorption.

Sutures

A type of fibrous joint consisting of a thin layer of connective tissue called a sutural ligament; they are only present in the skull.

Syndesmosis

A fibrous joint that occurs where two adjacent bones are linked by a ligament, where the ligament length determines the degree of movement.

Gomphosis

A fibrous joint consisting of short collagen fibres running between the root of a tooth and its bony socket; only occurs around the teeth.

Synchondroses (Primary)

A cartilaginous joint consisting of a bar or plate of hyaline cartilage, such as an epiphyseal plate between two ossification centres.

Symphyses (Secondary)

A cartilaginous joint where fibrocartilage connects two separate bones and permits limited movement, such as intervertebral discs or the pubic symphysis.

Synovial membrane

The highly vascular inner layer of the joint capsule that produces synovial fluid to fill the synovial cavity.

Fibrous membrane

The outer layer of the joint capsule made of dense connective tissue which may thicken to form ligaments.

Intracapsular

A term describing structures located inside of the joint capsule.

Plane joint

A nonaxial synovial joint with flat articular surfaces that allows sliding or gliding movements, such as intercarpal joints.

Hinge joint

A uniaxial synovial joint that allows movement at right angles to the joint, specifically $\text{flexion}$ and $\text{extension}$, such as the elbow joint.

Pivot joint

A uniaxial synovial joint that allows rotation in line with the longitudinal axis of the bones, such as the proximal radioulnar joint or the atlantoaxial joint.

Condylar (Condyloid) joint

A biaxial synovial joint with oval articular surfaces that allows $\text{flexion}$, $\text{extension}$, $\text{adduction}$, and $\text{abduction}$, such as the metacarpophalangeal (knuckle) joints.

Saddle joint

A biaxial synovial joint where articular surfaces are both concave and convex, such as the first carpometacarpal joint of the thumb.

Ball-and-socket joint

A multiaxial synovial joint where a spherical head fits into a cup (socket), allowing $\text{flexion}$, $\text{extension}$, $\text{adduction}$, $\text{abduction}$, $\text{circumduction}$, and $\text{rotation}$.

Articular discs and menisci

Accessor structures made of fibrocartilage that extend inward from the articular capsule to help absorb compression forces and may divide the joint cavity.

Labrum

A fibrocartilage lip that extends from the edge of the joint socket, prominently found at ball-and-socket joints to deepen the socket.

Fat pads

Intracapsular but extrasynovial accessory structures that act as space fillers and help spread synovial fluid.

Bursa

Fluid-filled bags of lubricant that work to reduce friction within a joint.

Tendon sheaths

Flattened fibrous sacs lined with synovial fluid that wrap around tendons, common in joints with greater mobility.

Range of Motion (ROM)

The range, measured in degrees of a circle ($360^{\circ}$), through which the bones of a joint can be moved.