Chapter 9 - Articulations

Question 1

functional classification is based on…

Answer 1

the degree of movement permitted

Question 2

name and describe the 3 functional classifications of joints.

Answer 2

synarthroses - immovable (btw skull bones)
amphiarthroses - slightly movable
diarthroses - move freely

Question 3

structural classification is based on…

Answer 3

anatomy

Question 4

name and describe the 3 structural classifications of joints.

Answer 4

fibrous joints - bones held together by dense irregular CT
cartilaginous joints - bones held together by cartilage
synovial joints - have synovial cavity, bones held together by ligaments

Question 5

Describe fibrous joints

Answer 5

lacking cartilage and synovial cavity, usually synarthroses (little movment)

Question 6

what are 3 examples of fibrous joints?

Answer 6

Ex #1) Suture joints in skull
Ex #2) Syndesmoses- greater distance btw bones, more dense irregular CT than suture joints (btw radius and ulna)
Ex #3) Interosseous membranes – binds neighboring long bones

Question 7

Describe cartilaginous joints.

Answer 7

• consist of a bar of cartilage between two bones
• Usually amphiarthroses – little to no movement
  (ex) pubic symphasis, intervertebral discs

Question 8

Describe synovial joints

Answer 8

• Ligaments hold bones together
• Forms a synovial cavity composed of an outer fibrous capsule and inner synovial membrane
• *Always diarthroses (free moving)
• Articular cartilage on the ends of the bones

Question 9

describe synovial fluid and what secretes this.

Answer 9

• dense viscous fluid

- secreted by synovial membrane

Question 10

purpose of synovial fluid.

Answer 10

• reduces friction by lubricating the joint
• Absorbs shock
• Supplies oxygen and nutrients
• removes waste from cartilage

Question 11

name and describe the 2 accessory structures of synovial joints

Answer 11

ligaments –> considered to be outside joint
Bursae –> fluid filled structure to minimize friction (similar to synovial) but it is only found where there may be increased friction (extra padding) only where there is bone on bone

Question 12

define menisci and their purpose

Answer 12

• pads of dense fibrocartilage btw articular surfaces
• Provides additional strength and stability
• Fits bones of different space (fills space creating a tighter fit)
• Shock absorber
• More even weight distribution
• Nerve and blood supply

Question 13

list the 6 types of synovial joints from least to most mobile.

Answer 13

1. planar joint
2. hinge joint
3. pivot joint
4. condyloid joint
5. saddle joint
6. ball-and-socket joint

Question 14

describe the planar joint

Answer 14

• Flat bones sliding

ex) between carpals

Question 15

describe the hinge joint

Answer 15

• Looks like a hinged door

ex) Elbow joint

Question 16

describe the pivot joint

Answer 16

ex) atlas rotates around the axis

Question 17

describe the condyloid joint

Answer 17

• Convex oval structure

ex) Between radius and carpal joints

Question 18

describe the saddle joint

Answer 18

• Looks like a rider in a saddle

ex) Between thumb, metacarpal, and carpal

Question 19

describe the ball and socket joint

Answer 19

• Allows for a lot of movement and rotation

ex) Hip joint

Question 20

define Range of Motion (ROM)

Answer 20

the range, measured in degrees of a circle, through which the bones of a joint can be moved.

Question 21

what are the 4 factors that contribute to a joint’s ROM?

Answer 21

1. Structure or shape of articulating bones
2. Strength and tension of muscles and ligaments
3. Hormones
   ex) Relaxin increases flexibility of pubic symphysis, loosen between sacrum and hip during pregnancy
4. disuse - results in:
   - Accumulation of synovial fluid
   - Muscles atrophy

Question 22

gliding movements

Answer 22

simple back-and-forth and side-to-side movements.

• Limited in range of motion
• No significant alteration in angle between the bones
• At planner joints (intercarpal joins)

Question 23

angular movements

Answer 23

Increase or decrease the angle between bones

Question 24

name and describe the 6 types of angular movements

Answer 24

1. Flexion- decrease in angle
2. Extension- increase in angle
3. Hyperextension - move beyond anatomical position
4. Abduction - movement away from midline
5. Adduction - movement towards the midline
6. Circumduction - moving in a circle

Question 25

rotation

Answer 25

one bone moving around its own longitudinal axis Ex) shaking your head “no” Anterior surface of the bone moves towards midline of the body -Medial rotation -Lateral rotation

Question 26

name and describe the 2 types of rotational movement

Answer 26

1. Supination - movement of the forearm so the palm is upward (hold the soup) 2. Pronation movement of the forearm so the palm is turned downward (poor the soup)

Question 27

describe elevation and depression. what types of movements are these?

Answer 27

special movements 1. Elevation - upward movement ex) Close mouth 2. Depression - downward movement ex) Open mouth

Question 28

describe protraction and retraction. what types of movements are these?

Answer 28

special movements 3. Protraction - movement anteriorly 4. retraction - movement posteriorly

Question 29

describe inversion and eversion. what types of movements are these?

Answer 29

special movements 5. inversion - movement of the sole of the foot medially 6. eversion - movement of the sole of the foot laterally

Question 30

describe dorsiflexion and plantar flexion. what types of movements are these?

Answer 30

special movements 7. Dorsiflexion - bending the foot at the ankle in an upward direction (toward the dorsum) 8.Plantar flexion - pointing the toes; foot at an angle in a downward direction (towards plantar surface)

Question 31

describe opposition. what types of movement is this?

Answer 31

special movement | 9. Opposition - movement of the thumb across the palm to touch other fingers

Question 32

in a lever, what is a joints role?

Answer 32

fulcrum

Question 33

define effort

Answer 33

muscular contraction

Question 34

define resistance

Answer 34

weight of the body part opposes movement

Question 35

when does movement occur?

Answer 35

effort exceeds load

Question 36

mechanical advantages occur when....

Answer 36

load is closer to the fulcrum, and the effort is further away, only need small amount of effort

Question 37

1st class lever

Answer 37

fulcrum is between the effort and the resistance (load) - Few in the body ex) Atlanto-occipital joint in the neck

Question 38

2nd class lever

Answer 38

resistance is between the fulcrum and the effort | -Always producing a mechanical advantage

Question 39

3rd class levers

Answer 39

effort is between the fulcrum and the load. * *mechanical disadvantage - Get more movement out of this arrangement - most common in body

Question 40

define arthritis

Answer 40

swollen, stiff, painful joits

Question 41

osteoarthritis

Answer 41

- joint cartilage is lost through “wear and tear” | - Associated with aging, avoid it through exercising

Question 42

Rheumatoid

Answer 42

autoimmune disease – body is breaking down cartilage in the joint linnings

Question 43

Gouty

Answer 43

- Uric acid buildup (byproduct of protein degeneration) or accumulation in joints. - Hard to move joints because there is other “stuff” in the way

Question 44

ankylosing spondylitis

Answer 44

- inflammation affects joints in the vertebrae | - More common in men

Question 45

arthroplasty

Answer 45

-the surgical implantation of an artificial joint. The most commonly replaced are the hips, knees, and shoulders