Functional and Structural Classification of Joints

Study Notes

Functional Classification of Joints

Synarthroses: immovable joints that offer no movement.
Amphiarthroses: slightly movable joints, allowing limited motion.
Diarthroses: freely movable joints enabling a wide range of movement.

Structural Classification of Joints

Joints classified by binding material and presence of a joint cavity.
Types:
- Fibrous joints: no joint cavity, connected by fibrous tissue.
- Cartilaginous joints: connected by cartilage without a joint cavity.
- Synovial joints: have a joint cavity filled with synovial fluid.

Fibrous Joints

Characterized as immovable or synarthroidal joints.
Types include:
- Syndesmoses: slightly movable joints connected by ligaments.
- Sutures: immovable joints, primarily found in the skull.
- Gomphoses: peg-in-socket joints, such as the connections of teeth.

Syndesmoses

Type of fibrous joint that allows slight movement.
Example includes the tibiofibular joint.

Suture

A fibrous joint that is essentially immobile.
Commonly found in cranial sutures, connecting skull bones.

Gomphosis

A unique peg-in-socket fibrous joint seen in teeth.

Cartilaginous Joints

Bones connected by cartilage with no joint cavity.
Generally not highly mobile.
Types include:
- Synchondroses: joints with hyaline cartilage, often synarthrotic.
- Symphysis: joints where fibrocartilage unites two bony surfaces.

Synchondrosis

A type of cartilaginous joint where hyaline cartilage connects bony surfaces.
Examples include the epiphyseal growth plate and the rib-sternum connection.

Symphysis

Cartilaginous joint formed with fibrocartilage.
Examples are the pubic symphysis and joints between vertebrae.

Synovial Joints

Freely movable joints (diarthrodial) that have a fluid-filled cavity.
Include joints of the limbs facilitating extensive movement.

5 Distinguishing Features of Synovial Joints

Articulate cartilage: cushions and prevents bone ends from crushing.
Joint cavity: a small space that contains synovial fluid.
Synovial membrane: lines the joint cavity and secretes synovial fluid.
Joint capsule: outer fibrous layer composed of dense irregular CT, inner layer is loose CT.
Synovial fluid: lubricates joints, nourishes cartilage, and removes debris.

Plane Joint

Synovial joint allowing gliding or sliding motions.
Formed between two flat surfaces, exemplified by the AC joint.

Hinge Joint

Synovial joint facilitating uniplanar motion, particularly flexion and extension.
Notable example: elbow joint (Humero-ulnar joint).

Modified Hinge Joint

Type of synovial joint allowing flexion, extension, and rotation.
Example includes the knee joint.

Pivot Joint

Synovial joint that allows uniplanar rotation.
Permits spinning motion; examples are the atlantoaxial joint and proximal radio-ulnar joint.

Condyloid Joint

Synovial joint shaped like an egg, allowing biplanar motion.
Enables flexion, extension, abduction, adduction, and axial rotation; observed in MCP joints (knuckles).

Saddle (Sellar) Joint

Provides biplanar motion with movements in two different planes.
Example: CMC joint of the thumb.

Ball and Socket Joint

Synovial joint with the capacity for triplanar motion.
Allows movements like flexion, extension, abduction, adduction, and rotations; represented by the glenohumeral joint (shoulder).

Description

Explore the various classifications of joints in this quiz. Learn about immovable, slightly movable, and freely movable joints, as well as the structural types such as fibrous, cartilaginous, and synovial joints. Assess your knowledge of their characteristics and functions.