joint/articulation

Joint/Articulation

Classified by:•Structure (composition)•Function (range of motion)

Types of Joints

• Synarthosis –– Immovable Joints; usually joined by strong fibers– No joint cavity

• Examples: sutures, joint binding tooth to socket, growth plate

Amphiarthrosis• No joint cavity• Slightly movable joint• Composed of fibrous joints• Composed of cartilage joints• Example: Fibrous – Membrane between

radius and ulna

Examples: CartilageVertebra Discs, Pubic Symphysis

Diarthrosis/Synovial Joint

•Greater range of motion•Joint cavity is present•Contains synovial fluid

• Six General Characteristics– Articular Cartilage• Covered with hyaline cartilage

– Joint Cavity• Space filled with synovial

fluid– Articular capsule• Fibrous capsule found on the

periosteum of long bones– Synovial fluid• Viscous fluid contains

macrophages• lubricates

– Reinforcing ligaments– Fat Pads• Extra padding

Types of Synovial Joints

Pivot Joints• Allows for rotation• One bone rotates around

another

ExamplesAtlas and axis; Radius and ulna

Hinge Joints• One bone fits into another• Motion is along a single

plane

Examples: knee and elbow, phalanges

Ball and Socket

• Freely moving joint• Head of bone articulates

with fossa of another

Examples: glenoid fossa and humerous; acetabulum and femur

Gliding• Bones slide across one

another• Bones must have flattened

or curved faces to glide• Movement is limited

Examples: carpals, tarsals, between vertebra

Saddle• Shape resembles saddle• Permits angular motion;

including circumduction but not rotation

Examples: Thumb

Types of Movement

Gliding- two or more bones slide past each other

• Rotation – turning around the longitudinal axis of body– Pronation and

supination are a form of rotation

• Pronation- turn palms posterior

• Supination – turn palms anterior (Anatomical position)

• Terms only apply to movement of radius

Angular Movements -decrease or increase the angle between two bones

• Flexion – decreases the angle between two bones

• Extension – increases the angle between two bones

• Hyperextension – increase the angle by > 180°

Angular Movementsflexion, extension, adduction, abduction and

circumduction

• Abduction – move away from body’s midline– To be abducted

• Adduction – move toward body’s midline– Add to body

• Circumduction – cone- shaped movement

• Dorsiflexion – point the toe up (superior)

• Plantar flexion – point the toe down (inferior)

• Eversion – turn ankle laterally

• Inversion- turn ankle medially (most common way to twist ankle)

• Protraction- move body part anteriorly

• Retraction- move body part posteriorlyProtraction

Retraction

Elevation – movement of the body superiorly

Depression – movement of the body inferiorly