Joints And Levers Flashcards
Components of levers
Fulcrum (pivot)
Load
Effort
1st class lever
Fulcrum is between the effort and the load
2nd class lever
Load is between fulcrum and effort
3rd class lever
Effort is between the fulcrum and the load
Short vs long levers
Short: small distance/high load/low speed
Long: long distance/low load/high speed
Characteristics of joints
Cartilaginous
Fibrous
Synovial
Functional classifications of joints
Synarthrosis-immovable
Diarthrosis-freely moveable
Amphiarthrosis-slightly moveable
Synarthrosis
CT holds bones tightly Fibrous: -skull sutures Cartilaginous: -1st ten ribs
Amphiarthrosis
CT holds bones Fibrous syndemosis: -membrane between radius and ulna Fibre cartilaginous symphesis: -symphesis pubis between pubic bones
Diarthrosis
Synovial joints
- hyaline cartilage
- joint capsule
- synovial membrane
- synovial fluid
Hyaline cartilage
Hard and smooth
Lines surface of bones
Joint capsule
Double membrane
Reinforced by ligaments
Synovial membrane
Inner lining of joint capsule
Produce synovial fluid
Synovial fluid
Nourishes hyaline cartilage
Synovial joint classification via planes of rotation
Mono/uniaxial- 1 plane
Biaxial- 2 planes
Multiaxial- 2+ planes
Nonaxial- any plane
Synovial joint classification according to shape
Planar Hinge Pivot Ellipsoidal Saddle Ball and socket
Planar joint
- gliding
- nonaxial
- flat/slightly curved
- flexion/extension
Hinge
- uniaxial
- convex surface fits into concave surface
- abduction/adduction
Pivot
- uniaxial
- long axis rotation
- rotation
Ellipsoidal
- biaxial
- condyloid
- convex oval projection into oval depression
- pronation/supination
Saddle
- biaxial
- like Ellipsoidal
- mobile
- circumductiom
Ball and socket
- Tri/multiaxial
- ball fits into cup
- protraction/retraction
- inversion/eversion
- depression/elevation
Synovial joint features
Articulate discs/minisci
Bursae
Bursae
Synovial fluid sacs
Reduce friction
Shock absorbers
Form tubes/tendon sheathes (protect tendons where they pass over bones)
