Joints Flashcards
Joint
The place where two bones come together
What are the three types of joints?
- fibrous
- cartilaginous
- synovial
Fibrous joint
- immovable
- connects bones
(skull & pelvis)
Cartilaginous
- slightly movable
- bones attached by cartilage
(spine or ribs)
Synovial
- freely movable
(knees)
Factors affecting joint stability
- articular surfaces
- ligaments
- muscle tone
How do articular surfaces affect joint stability?
- shape plays minor role
- deep sockets/grooves provide stability
How do ligaments affect joint stability?
- ligaments = stronger joints
- mobility restricted
- so only stretch 6% beyond normal length before tear
How does muscle tone affect joint stability?
- constant, low level of contractile force
- keeps tension on ligaments
What are the six groups of synovial joints?
- ball & socket joints
- hinge joint
- pivot joint
- gliding joint
- saddle joint
- condyloid joint
Characteristics of Ball and Socket joint
- one end of bone shaped like ball
- fits into hollow socket at the end of another joint
- greatest range of movement
- held together by ligaments & tendons
Examples of ball and socket joint
- shoulder
- hip joints
Characteristics of hinge joint
- joining of two bone ends that have smooth surfaces
- shaped to move against each other with minimum friction
- extensive flexion & extension with small rotation
- strong ligaments
Examples of hinge joint
Knee joints
Characteristics of pivot joint
- end of one bone has a ‘peg’
- ‘peg’ fits into a ‘ring’ on the other bone
- only rotational movements
Examples of ball and socket joint
top of spinal column
- between axis & atlas bones of neck
- allows movements of head
Characteristics of gliding joint
- allows flexion & extension
- through a slight gliding motion
- between ends of small bones
Examples of gliding joint
- wrist
- ankle
Characteristics of saddle joint
- occurs where concave and convex surfaces meet
- allows movement of the joint forwards/backwards/left/right
- wide range of movement
Examples of saddle joint
Thumb
Characteristics of condyloid joint
- convex shape of bone end fits into concave shape of adjoining bone
- movement in all directions
- full rotations limited
Examples of condyloid joint
Wrist
What are the connective tissues around joints?
- cartilage
- tendons
- ligaments
Cartilage
- joints/ends of bone
- flexible
- cushions the joint
