1.7 Joints

Question 1

What is a joint?

Answer 1

Articulation between bony elements

Question 2

What are the 3 types of joints?

Answer 2

• Fibrous
• Cartilaginous
• Synovial

Question 3

Which joint type is ligamentous?

Answer 3

Fibrous joint

Question 4

What are 3 examples of fibrous joints?

Answer 4

• Sutures of skull
• Syndesmoses - equine metacarpals
• Gomphosis - periodontal ligaments

Question 5

Fibrous joints: suture characteristics and growth

Answer 5

Membrane between bone grows, Bone grows into membrane at suture

• Allow ~ flexibility at parturition
• Close in most species (not mice!)

Question 6

Fibrous joints: Syndesmosis & Gomphosis characteristics and examples

Answer 6

Bands of short ligaments
ex. Syndesmoses
- equine metacarpals

ex. Gomphosis
- periodontal ligament

Question 7

Cartilaginous (cartilage)

Answer 7

Synchondroses at growth plate

Symphyses
- mandible and pelvis midline
- between vertebral bodies

Question 8

Synarthroses

Answer 8

Fibrous/ semi-rigid

Question 9

Synovial = ?

Answer 9

Fluid filled cavity

Question 10

4 examples of synovial joints?

Answer 10

Elbow
Shoulder
Stifle
Hip

Question 11

Diarthroses

Answer 11

Freely movable

Question 12

Synchondrosis

Answer 12

Cartilagenous joint between epiphysis and diaphysis

Question 13

Symphysis: mandibular

Answer 13

• Some sp. mobility for mastication
• Common site of fracture in cats

Question 14

Symphysis: pelvic

Answer 14

Becomes softer before parturition (relaxin)

Question 15

Symphysis: intervertebral disc

Answer 15

movement facilitated by ligament-like fibrocartilage

Question 16

Physis means?

Answer 16

Sense of growing

Question 17

Answer 17

A) epiphysis (bone end)
B) joint capsule
C) synovial membrane
D) joint fluid
E) hyaline cartilage

Question 18

Hinge joint

Answer 18

Shapes to limit articulation to one plane

Question 19

Ball and socket joint

Answer 19

Wide, almost
Infinite, range of articulation

Question 20

Diarthrodial (synovial) joint definition

Answer 20

-fully moveable joint
-synovial cavity is between 2
articulating bones
-ROM defined by shape of articular surface
-synovium lubricates the 2 surfaces for
movement & covers them with a thin layer of
strong smooth articular cartilage

Question 21

Articular cartilage characteristics

Answer 21

-Most common type of cartilage
-assists the motion of joints by being slippery&
smooth so movement is smooth when bones
glide
-found around the bones of free-moving joints
-composed of chondrocytes &ECM
-surrounded by perichondrium (No
perichondrium on hyaline articular cartilage)

Question 22

Articular cartilage examples

Answer 22

-on the ends of long bones
-ribs
-nose
-on top of synovial joints

Question 23

Diarthrodial (synovial) joint subtypes

Answer 23

-gliding
-hinge
- pivot
-condyloid
-saddle
-ball and socket.

Question 24

synovium composition

Answer 24

Lining (intimal layer) + sub-intima

-Sub-intima is loose fibrous/fatty
-Produces a plasma ultrafiltrate
-No basement membrane
-Type A cells: (macrophage-like)
-Phagocytosis Type B cells (fibroblast-like): Produce synovial fluid

Question 25

Synovial sheath function

Answer 25

• Provide lubrication to tendons as they pass over joints
• Poor healing after trauma can lead to adhesion and loss of function

Question 26

Joint cavity function:

Answer 26

-In complex joints multiple cavities in a single
joint (example: equine carpus)

-may/may not communicate to each other due
to disease or individual issue

Question 27

Functions of cartilage?

Answer 27

• Resists compression
• Provides resilience
• Provides support
• Provides flexibility

Question 28

Elastic cartilage characteristics:

Answer 28

-Greater toughness in bending
-lot of elastic for more flexibility “less plastic
more elastic”
-Surrounded by perichondrium & often
merged with stiffer connective tissues for support

Question 29

Fibrocartilage (non-articular
cartilage) characteristics

Answer 29

-Additional resistance to tension
-Type-| collagen in bundles, less
proteoglycan
-Fibrochondrocytes between ECM bundles
-No perichondrium