2.2 Articulations

Question 1

Joints (articulations)

Answer 1

-point of contact between: *bones
*bones and cartilage
*bones and teeth
-can involve bony surface+ tendons + ligaments + cartilage + muscles + accessory structures

Question 2

Joints (articulations) major functions

Answer 2

• skeletal mobility
• structural support
• protection
  *greater mobility = less stability
• lesser mobility = greater stability

Question 3

classification of joints

Answer 3

• based on function:
  *synarthrosis (immovable)
  *amphiarthrosis (slightly movable)
  *diarthrosis (freely movable)
• based on structure:
  *fibrous
  *cartilaginous
  *synovial

Question 4

functional classification

Answer 4

• Synarthroses: immovable joints
  ex: cranial sutures
• Amphiarthroses: slightly movable joints
  ex: pubic symphysis
• Diarthroses: freely movable joints
  ex: most appendicular joints

Question 5

fibrous

Answer 5

(immovable)
- joined by fibrous tissue (dense fibrous connective tissue)
- no joint cavity present

Question 6

cartilaginous

Answer 6

(immovable or slight movable)
- joined by cartilage tissue
- no joint cavity present

Question 7

synovial

Answer 7

(freely movable)
- most common type
- bones separated by fluid-filled joint cavity

Question 8

syndesmosis

Answer 8

fibrous joint
- connection via ligaments
- little movement
ex: tibia/fibula

Question 8

suture

Answer 8

fibrous joint
- seam of connective tissue that interlocks bone
- immovable
ex: cranial structure

Question 9

gomphosis

Answer 9

fibrous joint
- peg-in socket joint
- immovable
ex: tooth & jaw

Question 10

synchondrosis

Answer 10

cartilaginous joints
- hyaline cartilage connects bone
- immovable joints

Question 11

symphysis

Answer 11

cartilaginous joints
- fibrocartilage connects bone
- shock absorption + limited range of motion

Question 12

synovial joints

Answer 12

• bone separated by fluid-filled joint capsule
• freely movable joint
• most joints of the body

Question 13

articular cartilage

Answer 13

synovial joints
- layer hyaline cartilage
- reduce shock, friction

Question 14

joint cavity

Answer 14

synovial joints
- filled with accessory structures and small amount of synovial fluid

Question 15

joint capsule

Answer 15

• fibrous capsule - dense irregular connective tissue that is continuous with the periosteum
• synovial membrane - loose connective tissue
  *covers everything not covered by articular cartilage
  *makes synovial fluid

Question 16

synovial fluid

Answer 16

• fills open space within the joint (typically <3 mL)
• lubricates articular cartilages to reduce friction, absorbs shock, carries nutrients via diffusion to chondrocytes
• largely made of hyaluronic acid and lubricin (polysaccharide)

Question 17

reinforcing ligaments

Answer 17

• support, strength, reinforce
• can be inside (intracapsular) or outside (extracapsular) the joint capsule
• most common = thickened portion of fibrous layer of articular capsule

Question 18

nerves and blood vessels

Answer 18

• sense movement at joints
• rich blood vessel supply to synovial membrane

Question 19

fat pads

Answer 19

synovial joints - accessory structure:
- packing material at periphery, fill space as bone move

Question 20

articular discs

Answer 20

synovial joints - accessory structure:
- pads of fibrous cartilage
- AKA meniscus

Question 21

tendons

Answer 21

synovial joints - accessory structure:
- pass through or around joint

Question 22

bursae

Answer 22

synovial joints - accessory structure:
- bags of synovial fluid
- reduce friction and absorb shock
- common where tendons, ligaments, muscles, skin, or bones typically rub

Question 23

articular surface

Answer 23

synovial joints - stabilizing factors
- shapes dictates possible movement at joint
ex: hip vs. shoulder joints

Question 24

ligaments

Answer 24

synovial joints - stabilizing factors - capsules & ligaments restrict range of motion - more ligaments --> stronger joint - work with other structures for stability

Question 25

muscle tone

Answer 25

- constant, low level of skeletal muscle contraction --> taught tendons --> more stable joint - stronger muscles around joint --> greater tone --> greater stability

Question 26

synovial joint type

Answer 26

- ball & socket - pivot - hinge - plane - condylar - saddle

Question 27

articulation example

Answer 27

- direct relationship between structure and function ex: shoulder, hip, knee

Question 28

synovial joints - shoulder

Answer 28

- ball & socket joints ball = head of the humerus socket = glenoid cavity of the scapula - greatest range of motion of any joint in the body ex: *bones (humerus & scapula) *ligaments (coracohumeral) *cartilage ( glenoid labrum) *muscle + tendons (rotator cuff) *bursae (subdeltoid)

Question 29

synovial joints - hip

Answer 29

- ball & socket joint: ball = head of femur socket = acetabulum of the os coxae - deeper socket = lesser range of motion than the shoulder = greater stability ex: *bone (femur & os coxae) *ligaments (iliofemoral) *cartilage (labrum) *bursae (greater trochanteric) *muscles (gluteal group)

Question 30

subluxation

Answer 30

- partial dislocation of the joint ---> little tissue damage - head of femur comes completely away from acetabulum->dislocation

Question 31

synovial joints - knee

Answer 31

- supports body weight (and greater) - hinge joint + slight rotation when flexed: *tibia + femur *fibula + femur ex: *bone (femur, fibula, tibia) *cartilage (lateral meniscus) *bursae *fat pads *ligaments - muscles (quadriceps & hamstrings groups)

Question 32

cartilage tears

Answer 32

break in continually of cartilage ex: meniscus

Question 33

sprains

Answer 33

stretching or tearing of tendons/ligaments ex: ankle

Question 34

dislocations

Answer 34

bones at joint are forced out of alignment ex: shoulder

Question 35

bursitis/tendonitis

Answer 35

inflammatory/ degenerative diseases that affect joints

Question 36

arthritis

Answer 36

collection of inflammatory / degenerative diseases that affect joints