Exam 4 - Joints Flashcards
Articulation (joint)
place where 2 bones come together
Arthrology
study of joints
Kinesiology
study of musculoskeletal movement
How are joints classified?
By substance “between” adjacent bones and “flexibility”
Joint classifications
SSAD Bony - synostosis Fibrous - synarthrosis Cartilaginous - Amphiarthrosis Synovial - Diarthrosis
Synostosis
no movement because joint disappears
Synarthrosis
little or no movement
Amphiarthrosis
slightly moveable
Diarthrosis
freely movable
What makes up the joint capsule?
fibrous capsule and synovial membrane
Fibrous capsule
dense irregular connective tissue, continuous w/ fibrous layer of the periosteum
- portions may thicken to from ligaments
Tendons attach…
muscle to bone
Ligaments attach…
bone to bone
Synovial membrane
membrane lines inside of joint capsule EXCEPT at actual articulation of articular cartilages
Synovial fluid
complex mixture of polysaccharides, HYALURONIC ACID, proteins, fat, and cells
- slippery and serves as lubricant
- also “feeds” cartilage (cartilage doesn’t have a blood supply)
Bursa
saclike extension of joint capsule (pockets of synovial membrane)
- lie between nearby structures so they can slide more easily past each other
Tendon sheaths
cylinders of connective tissue lined w/ synovial membrane and wrapped around a tendon
Shoulder joint axes
Has 3 degrees of freedom = multiaxial joint
6 classes of synovial joints
- ball and socket
- pivot joint
- saddle joint
- hinge joint
- gliding joint
- condyloid joint
Range of motion
degrees through which a joint can move
What determines range of motion?
- articular surfaces
- strength and tautness of ligaments, tendons, and capsule
- action of muscles and tendons
Stretching of ligaments
increases range of motion
“double-jointed” people
have long or slack ligaments
Lever
rigid object that rotates around a fixed point called a FULCRUM
When does movement occur?
When EFFORT overcomes RESISTANCE
- resistance arm and effort arm are described relative to fulcrum
Classes of levers:
FRE
First class level
Load FULCRUM Effort
Second class lever
Fulcrum RESISTANCE/LOAD Effort
Third class lever
Resistance/load EFFORT FULCRUM
Types of lever produce either increase in…
speed or force
Example of levers that help increase output of force
Human moving a heavy object w/ help of crowbar
Levers that move objects further and faster
Movement of row boat w/ paddle
Mechanical advantage equation
length of the effort arm divided by length of resistance arm
E/R
MA = 1
no advantage or disadvantage
MA < 1
disadvantage or low power, but high speed (effort arm is shorter than resistance arm)
MA > 1
advantage or high power, but low speed (effort arm is longer than resistance arm)
Flexion
decreases angle of a joint
Extension
straightens and returns to the anatomical position
Hyperextension
extension beyond 180 degrees
Adduction
movement TOWARD THE MIDLINE
Hyperadduction
crossing fingers
Abduction
movement of a part AWAY FROM THE MIDLINE
Hyperabduction
raise arm over back or front of head
Elevation
movement that RAISES A BONE VERTICALLY
- mandibles are elevated during biting and clavicles during a shrug
Depression
lowering the mandible or the shoulders
Protraction
movement anteriorly on horizontal plane
- thrusting the jaw, shoulder or pelvis forward
Retraction
movement posteriorly
Circumduction
movement in which one end of appendage remains stationary while the other end makes a circular motion
- REALLY A SEQUENCE OF FLEXION, ABDUCTION, EXTENSION, AND ADDUCTION MOVEMENTS
Rotation
movement on longitudinal axis
Medial roation
turns bone inwards
Lateral rotation
turns bone outwards
Supination in the forearm and foot
- rotation of forearm so that the PALM FACES FORWARD
- plantar flexion, inversion and adduction of foot
Pronation “pro dribbling a basketball” in the forearm and foot
- rotation of forearm so the palm faces to the rear
- dorsiflexion, eversion and abduction of foot
Radial flexion
toward the radius (toward the side of the thumb)
Ulnar flexion
toward the ulna (away from thumb)
What injuries in the ankles do we see more of?
Inversion
Arthritis
broad term for PAIN AND INFLAMMATION OF JOINTS
Osteoarthritis
- results from years of joint wear
- articular cartilage softens and degenerates
- bone spurs develop on exposed bone tissue causing pain
- not an inflammatory response
Rheumatoid arthiritis
caused by an AUTOIMMUNE ATTACK ON JOINTS
- antibodies attack synovial membrane, enzymes in synovial fluid DEGRADE THE CARTILAGE
- inflammatory process
Arhtroplasty
replacement of diseased joint w/ artificial device called PROSTHESIS
