Articulations Flashcards
Types of joints:
Based on range of motion
1) Synarthrosis: immovable
Example: cranial sutures & epiphyseal cartilage
2) Amphiarthrosis: slightly moveable
Example: radius/ulna shafts & Pubic symphysis
3) Diarthrosis: freely moveable (synovial joints)
Example: joints in limbs
Joint classifications based on cartilage type
1) Fibrous cartilage- sutures (2 bones connected by ligaments)
2) Cartilaginous- synchondrosis & symphysis
3) synovial- all joints
Diarthrosis (synovial joints)
Joint structure, articular cartilage, synovial membrane, joint cavity contains synovial fluid, joint capsule, periosteum
Function of synovial fluid
1) lubrication; low friction coefficient
2) nourishment for chondrocytes; regulated by joint movement
3) shock absorption; distributes forces evenly over articular cartilages
Diarthrosis
Accessory structures
- not all joints have these *
- bursa
- meniscus
- extracapsular/ intracapsular ligament
- tendons
- fat pad
Diarthrosis
Functions of accessory structures
1) menisci- fibrous cartilage pads for shock absorption
2) fat pads- fill spaces created when joint changes shape
3) ligaments & tendons - support joints & limit movement
4) bursae- synovial fluid-filled pockets surrounded by synovial membrane. Reduce friction/ shock absorption
Joint vs. mobility (range of motion)
Factors affecting mobility
- shape of articulating surfaces
- types/quantity of accessory structures
Very strong = less mobility
Can’t be both
Structure= function
Joint movements
Types of planes
1) coronal plane
Joints: shoulder, hip, wrist, metatarso-phalangeal, & metacarpo-phalangeal
2) sagittal plane
Joints: vertebral column joints, elbow, hip, knee, wrist, fingers, toes
3) transverse plane
Joints: atlas/axis joint, shoulder, hip, radioulna joints (supination & pronation only)
Joint movements
- abduction: movement away from body
- adduction: movement away from body
- flexion: decreases the angle or distance between two bone segments
- extension: increases the angle or distance between two bone segments
- rotation
- pronation/supination
- lateral flexion
- depression/ elevation (shrug shoulders)
- retraction/ protraction (jaw)
Special movements of ankle
- eversion/ inversion
- dorsiflexion/ plantarflexion
Axis of motion
1) Mono axial: movement in 1 planes
Example: ankle & elbow
2) biaxial: movement in 2 planes
Example: ribs & wrist
3) triaxial: movement in 3 planes
Example: shoulder & hip
Joints
Arthroses
Connection between bones that may or may not permit movement
Gliding joint
Amphiarthrosis, Slight movement
Mono axial
Example: sternoclavicular, acromioclavicular, intercarpal, intertarsal joints
Pivot joint
Rotation
Mono axial
Amphiarthrosis
Example: atlas/axis joint
Saddle joint
Biaxial
Angular motion
Example: first carpometacarpal joint
Hinge joint
Mono axial
Amphiarthrosis
Angular motion like a door
Example: knee & elbow
Ellipsoid joint
Biaxial
Angular motion
Example: metacarpophalangeal
Ball-and-socket joint
Triaxial
Diarthrosis
Angular motion and rotation
Example: shoulder and hip joint
Gliding joint
Amphiarthrosis, Slight movement
Mono axial
Example: sternoclavicular, acromioclavicular, intercarpal, intertarsal joints
Pivot joint
Rotation
Mono axial
Amphiarthrosis
Example: atlas/axis joint
Saddle joint
Biaxial
Angular motion
Example: first carpometacarpal joint
Hinge joint
Mono axial
Amphiarthrosis
Angular motion like a door
Example: knee & elbow
Ellipsoid joint
Biaxial
Angular motion
Example: metacarpophalangeal
Ball-and-socket joint
Triaxial
Diarthrosis
Angular motion and rotation
Example: shoulder and hip joint
Anterior crucial element ligament
ACL
Connects across
Prevents the tibia from moving too far anteriorly relative to the femur
Posterior cruciate ligament
PCL
Prevents tibia moving too far posteriorly relative to femur
