Joints

Question 1

What are the two classes of joints

Answer 1

Synarthroses
Diarthrosis/synovial

Question 2

What are the five types of synarthroses

Answer 2

synostosis
synchondrosis
symphysis
syndesmosis
gomphosis

Question 3

Synostosis

Answer 3

two bones connected by bone (fused)
mature skull, mature pelvis

Question 4

Synchondrosis

Answer 4

two bones connected by cartilage
growth plate

Question 5

Symphysis

Answer 5

Two bones connected fibrocartilage
early pelvic, mandibular

Question 6

Syndesmosis

Answer 6

two bones connected by fibrous tissue
early skull, distal tibio-fibular

Question 7

Gomphosis

Answer 7

fibrous joint between tooth and socket

Question 8

What are the six types of synovial joints

Answer 8

ball and socket
Ellipsoidal
Saddle
Hinge
Pivot
Planar/sliding

Question 9

What separates synarthroses from diarthrosis joints

Answer 9

diarthrosis are more mobile joints

Question 10

Ball and socket

Answer 10

enarthrosis
hip
3 axis

Question 11

Ellipsoidal

Answer 11

no rotation, more restricted than ball and socket
2 axis

Question 12

Saddle

Answer 12

sellar
interphalangeal
2 axis
‘‘2 pringles on top of each other’’

Question 13

Hinge

Answer 13

ginglymus
hock, elbow
1 axis

Question 14

Pivot

Answer 14

trochoid
C1/C2
cat radioulnar
1 axis

Question 15

Planar/sliding

Answer 15

arthrosis
intercarpal, intertarsal
unusual - translation not rotation

Question 16

Synovial membrane

Answer 16

glistening pink, many vessels and nerves
often incomplete, no basement membrane
folded or tufted
often large pouches to allow movement

Question 17

Cells in the synovial membrane

Answer 17

synoviocytes type A = phagocytic
Synoviocytes type B = secretory (of synovial fluid)

Question 18

Synovial Fluid

Answer 18

secreted by type B synoviocytes
plasma ultrafiltrate + hyaluronate
(long chains of glycosaminoglycan)
lubricate, nutritive

Question 19

What position is the high energy state in snap joints of horses

Answer 19

intermediate position
as collateral ligaments are stretched rather than relaxed

Question 20

How is articular cartilage fed

Answer 20

fed by diffusion from fluid>capsule>underlying bone
no vessels or nerves

Question 21

What is the physical structure of articular cartilage

Answer 21

arcade of arches arrangement of collagen

Question 22

What is the molecular structure of articular cartilage

Answer 22

based on glycosaminoglycan (GAG)
proteoglycans are attached to long GAG chains
Proteoglycans are a core protein with a shorter GAG sidechain

Question 23

What are the two matrix meshes of articular cartilage

Answer 23

Type II collagen protein mesh - resits tension
Hyaluronate polysaccharide mesh - resist compression

Question 24

How does the Hyaluronate polysaccharide mesh resist compression

Answer 24

Hydrophilic proteoglycans are negatively charged so repel each other and attract water

Question 25

What is the effect of retaining water in articular cartilage

Answer 25

water will weep in and out of joint space in varying pressures so: - lubricates joint - carries dissolved nutrients and gases to the articular cartilage

Question 26

Capsules

Answer 26

fibrous capsule attaches to periosteum continuous with articular cartilage supports joint

Question 27

Collateral ligaments

Answer 27

restrict the movement of the joint to one plane (sagittal plane) - hinge movements Much innervation - proprioception, respiratory reflexes

Question 28

Menisci

Answer 28

fibrocartilage ingrowths from capsule incomplete, c-shaped, 2 in each stifle joint

Question 29

Discs

Answer 29

fibrocartilage ingrowths from capsule allocate different movements to different compartments (separate joint in two) 1 in each jaw joint

Question 30

Labra

Answer 30

fibrocartilaginous extension to the joint surface hip joint

Question 31

Fat pads

Answer 31

lie between synovial membrane and capsule - padding the joint

Question 32

Bursae

Answer 32

small spaces between bones and the: - tendon -biceps and humerus in horses - occasional muscles

Question 33

What clinical condition can reduce joint function

Answer 33

degeneration of either the collagen or glycosaminoglycan meshes