Joints Flashcards
what is another name for joint?
articulations
site where two or more bones meet
joint
function of a joint
- gives skeleton mobility
- holds skeleton together
structural classifications of a joint (based on type of material binded to joint)
- fibrous
- cartilaginous
- synovial (cavity)
functional classification of a joint, (based on the movement the joint allows)
- synarthrosis
- amphiarthrosis
- diarthrosis
synarthrosis
immovable, ex: skull
amphiarthrosis
slightly movable, ex: pubic symphysis, and vertebrae
diarthrosis
freely movable, ex: knees, ankles, fingers, etc.
Three types of fiberous joints
sutures
syndesmoses
gomphoses
sutures
joints of the skull, protect the brain
syndesmoses
-Bones connected by ligaments, bands of fibrous tissue
-Short fibers offer little to no movement
-Ex: inferior tibiofibular joint
-Long fibers offer a larger amount of movement
-Ex: interosseous membrane connecting radius and ulna
Gomphoses
Peg-in-socket joints
Ex: teeth
Held in by periodontal ligament
Cartilaginous joints
-United by cartilage
-No joint cavity
-Not highly movable
-Synchondroses - bar or plate of hyaline cartilage unites bones
-Ex: cartilage of 1st rib with manubrium of sternum
-Sympheses - joined by hyaline and articular cartilage
-Are slightly movable
-Ex: intervertebral joints, pubic symphysis
Synovial joints
All have fluid filled joint cavity
All are diarthrotic, freely movable
All share 6 characteristics
6 characteristics of synovial joints
- Articular cartilage
- Consists of hyaline cartilage
- Prevents crushing of bone ends - Joint (synovial) cavity
- Articular joint capsule
- Fibrous layer → external
- Inner synovial membrane → internal - Synovial fluid
- Lubricates and nourishes cartilage
- Phagocytic cells - Reinforcing ligaments
- Capsular - thickened part of fibrous layer
- Extracapsular - outside the capsule
- Intracapsular - deep to capsule; covered by synovial membrane - Nerves and blood vessels
- Nerves detect pain; monitor joint position and stretch
- Blood vessels supply filtrate for synovial fluid
Other features of synovial joints
-Fatty ads for cushioning
-Discs - menisci
Made of fibrocartilage
Improve fit
Stabilize joint
Reduce wear and tear
-Bursae
Bags filled with synovial fluid “ball bearing”
Reduce friction where ligaments, tendons, muscles, skin, and bones rub together
-Tendon sheaths
Bursae that wrap around tendons
Joint stability
-Shape of articular surface
Minor role
Shallow are less stable than ball-and-socket
-Ligament number and location
More ligaments = more strong joint
-Muscle tone
Most important for reinforcing knee and shoulder
Movements
-All muscles attach bones or connective tissue at no fewer than two points
-Origin - attachment to immovable bone
-Insertion - attachment to moveable bone
Gliding
princess wave
Flexion
Angle smaller
extension
angle bigger
hyperextension
Angle beyond normal position
abduction
Take away from body
adduction
bring to (add) body
Circumduction
circle movement
Medial rotation
Turn head/foot to middle from side
lateral rotation
Turn head/foot to side from middle
supination
Bowl of soup → palm up
pronation
No soup → palm down
Dorsiflexion FOOT ONLY
toes to ceiling
Plantar flexion FOOT ONLY
toes to floor
Inversion
inward twist
eversion
outward twist
protraction JAW
stick out chin
retraction JAW
pull chin back in
elevation JAW AND SHOULDER
lifting
depression JAW AND SHOULDER
dropping
synovial joint types
-Plane → carpals
-Hinge → elbow
-Pivot → between radius and ulna → –allows us to flip board
-Condylar → between phalanges and -metacarpals → biaxial
-Saddle → thumbs
-Ball-and-socket → shoulder and hips
