Lecture 8

Question 1

What is a joint?

Answer 1

• Where bones together
• Where bones meet = articulation
• Involves bone shapes and soft tissues
• Allow free movement or control movement

Question 2

Which soft tissues are involved with joints?

Answer 2

• Have no inorganic components
• Cartilage
  > hyaline/articular cartilage
  > fibrocartilage

Question 3

What is the general cartilage composition?

Answer 3

• Collagenous fibers embedded in a firm gel, no canal system therefore avascular (much slower to heal)
• Chondrocytes live in lacuna
• Nutrients diffused through matrix by joint loading
  (not vascular, not regenerate)

Question 4

What is the structure of cartilage?

Answer 4

Hyaline cartilage
> collagen fibres are barely visible 
> high water content in matrix
> function: resist compression
> provide smooth frictionless surface 

Fibrocartilage
> collagen fibres form bundles throughout matrix
> orientation of fibres align with stresses
> function: resist compression and tension

Question 5

What is the function of cartilage in joints?

Answer 5

Hyaline cartilage
> to provide frictionless movement of bones in synovial joint
> moulds to surfaces of the bones where they articulate
> degrades with age
> loses water content
> trauma = can cause damage

Fibrocartilage
> e.g. meniscus = cartilage of knee joint
> concave discs of fibrocartilage
> deepens the articulation of knee
> can adopt its shape to stresses on joint in movement

Question 6

What bony congruence?

Answer 6

• The sum of the bone surfaces that form an articulation

- Less bony congruence equals more soft tissue support

Question 7

What are ligaments?

Answer 7

• Bone to bone
• Restrict movement
• Movement is restricted ‘away from itself’
• e.g. lateral restricts adduction
• e.g. medial restricts abduction

Question 8

What are tendons?

Answer 8

• Muscle to bone
• Function = facilitates and controls movement
• Contraction

Question 9

What is elastic cartilage?

Answer 9

Large numbers of darkly stained elastic fibers confer the elasticity & resiliency typical of this cartilage

Gives form to the external ear, epiglottis, eustachian or auditory

Question 10

What are two ways growth occurs in cartilage?

Answer 10

• Interstitial growth = results in the increase of the diameter or thickness of the cartilage.
• Appositional growth = results in an increase of cartilage mass and occurs from within.

Question 11

What is the nucleus pulposus?

Answer 11

Nucleus pulposus is the inner core of the vertebral disc. The core is composed of a jelly-like material that consists of mainly water, as well as a loose network of collagen fibers.