Lecture 6 - Joints

Question 1

functions of joint

Answer 1

• > give skeleton mobility

- > holds skeleton together

Question 2

classification of articulations

Answer 2

• > functional (what does it do?)

- > structural (what is it made of)

Question 3

functional classification of joints

Answer 3

• > synarthroses (immovable)
• > amphiarthroses (slightly movable)
• > diarthroses (freely movable, to an extent)

Question 4

structural classification of joints

Answer 4

• > fibrous joints
• > cartilaginous joints
• > synovial joints

Question 5

types of fibrous joints

Answer 5

• > sutures
• > syndemoses
• > gomphoses

Question 6

characteristics of sutures

Answer 6

• > rigid, immovable, interlocking joints

- > in middle age, sutures ossify and fuse (synostoses)

Question 7

characteristics of syndemoses

Answer 7

• > a joint held together by a ligament

- > fibre length varies therefore so does movement

Question 8

characteristics of gomphoses

Answer 8

• > fibrous connection (periodontal ligament) which holds the tooth in the socket

Question 9

types of cartilaginous joints

Answer 9

• > synchondroses

- > symphyses

Question 10

characteristics of cartilaginous joints

Answer 10

• > bones united by joints
• > no joint cavity
• > partially movable

Question 11

what is a synchondroses joint

Answer 11

an immovable joint which unites bones with hyaline cartilage

ie. growth plate

Question 12

what is a symphyses joint

Answer 12

a slightly movable joint made of fibrocartilage which connects bone to bone
ie. intervertebral disks

Question 13

characteristics of synovial joints

Answer 13

• > freely movable
• > connection between two bones separated by a fluid-filed joint cavity
• > include all limb joints; most joints in the body

Question 14

What are the 6 feature of synovial joints

Answer 14

1. articular cartilage: hyaline cartilage (prevents friction)
2. joint cavity (filled with synovial fluid)
3. Articular capsule (2 layers)
4. Synovial fluid
5. different types of reinforcing ligaments (3)
6. nerve and blood vessels

Question 15

what are the two layers of the articular capsule?

Answer 15

• > External fibrous layer (dense connective tissue)

- > Internal synovial membrane (loose connective tissue which makes synovial fluid)

Question 16

What is synovial fluid

Answer 16

• > made of plasma and hyaluronic acid
• > it lubricates and nourishes articular cartilage
• > contains phagocytic cells to remove debris
• > in the joint cavity

Question 17

what are the different reinforcing ligaments of a synovial joint

Answer 17

capsular - > thickened layer of fibrous layer
extracapsular - > outside the capsule
intracapsular- > deep to capsule; covered by synovial menbrane

Question 18

what does it mean to be double jointed

Answer 18

when your ligaments and joint capsules are loose and/or stretchy

Question 19

Which structures do only some synovial joint have

Answer 19

• > fatty pads

- > articular discs

Question 20

What is the function of fatty pads?

Answer 20

They’re for cushioning between fibrous layer and synovial membrane or bone ie. hip/knee

Question 21

What are articular discs

Answer 21

also known as menisci
they’re fibrocartilage which separates articular surfaces to improve “fit” of bone, stabilize joint and reduce wear and tear

Question 22

What structures are associated with synovial joints but aren’t apart of the joint itself

Answer 22

• > bursae

- > tendon sheaths

Question 23

What are bursae

Answer 23

they’re sacs lined with a synovial membrane and filled with synovial fluid which help reduce friction at the joint

Question 24

what are tendon sheaths

Answer 24

a layer of synovial membrane (elongated bursa) which wrap around tendon to reduce friction

Question 25

what are the three stabilizing factors of synovial joints

Answer 25

• > shapes of articular surfaces (minor role)
• > ligaments number and location (limited role)
• > muscle tendons that cross joints (most important)

Question 26

origin vs insertion

Answer 26

origin - > portion of the muscle attached to immovable . bone (superior end of bicep)
insertion - > portion of muscle attached to movable bone (inferior end of bicep)

Question 27

What are gliding movements

Answer 27

when one flat bone surface glides and slips over another

ie. carpal bones

Question 28

List all the types of angular motions of joints and how they move

Answer 28

• > flexion (muscle shortens)
• > extension (lengthens)
• > hyperextension (too far)
• > Abduction (limb away from body)
• > adduction (limb towards body)
• > circumduction (circle)

Question 29

What is hyperextension

Answer 29

excessive extension beyond normal range of motion

Question 30

List all the types of rotations of joints and how they move

Answer 30

• > internal rotation (towards body)
• > external rotation (away body)
  ie rotation of humerus and femur (must be bent)

Question 31

List all the types of special motions of joints and how they move

Answer 31

• > pronation (palm back) and supination (palm forward)
• > dorsiflexion (foot-shin) and plantar flexion (point)
• > inversion (roll ankle) and eversion (break ankle)
• > protraction (sick out) and retraction (retract)
• > elevation (up) and depression (down)
• > opposition (ballgaze)

Question 32

What are the different shapes of synovial joints?

Answer 32

• > plane joints
• > hinge joints
• > saddle joints
• > ball-and-socket joint
• > condylar joint (ball and socket but more oval; restricted)
• > pivot joint