1.6 Joints

Question 1

List some joint issues

Answer 1

1. Synovitis
2. Bursitis
3. Infection
4. Hip dysplasia
5. Hyperflexibility
6. Luxation/dislocation
7. Ligament injuries

Question 2

What are synovial joints?

Answer 2

Joint space surrounded by synovial membrane which in most joints is strengthened by a fibrous joint capsule \

• most common type of joint
• articulating bones separated by fluid filled space

Question 3

What is arthroscopy?

Answer 3

Joint scope

Question 4

What is articular (hyaline) cartilage?

Answer 4

Hyaline cartilage provides the interface between bones at a synovial joint

Question 5

How does hyaline cartilage work?

Answer 5

Provides extremely low coefficient of friction and lubricates joints to allow movement
- no nerves or blood vessels therefore has a limited capacity for healing/repair

Question 6

What makes up cartilage?

Answer 6

Cells - chondrocytes
Collagen and other organic matrix components
Water - 65-90%
Regional variation

Question 7

What is synovial fluid?

Answer 7

Essentially a transport network

• secreted by synovial membrane
• clear/straw coloured viscous fluid
• contains hyaluronic acid

Question 8

What is the menisci?

Answer 8

Formed of fibrocartilage
- more fibrous
- higher collagen content - more shock absorption
- stiffer
Load distribution help make the joint make better contact

Question 9

What is the bursae?

Answer 9

Occur where there is rubbing/problematic locations for joints
- entirely synovial membrane

Question 10

What are the tendon sheaths?

Answer 10

Like bursae but wrap around tendon where they pass over joints - present around long distal ligaments

Question 11

Describe the blood and nerve supply to articular cartilage

Answer 11

1. Free sensory (pain) fibres from joint capsule and synovial membrane
2. Efferent fibres
3. Sensory fibres from blood vesels
4. Proprioceptive fibres from joint capsule

Question 12

What is a fibrous joint?

Answer 12

Often restrict motion i.e., cranium, radius + ulna (stops lateral movement)

Question 13

What is a cartilaginous joint?

Answer 13

In between vertebrae
Pubic symphysis
- entirely joined by cartilage

Question 14

What is a synsarcosis?

Answer 14

Joints formed entirely of muscle

Question 15

What are the degrees of translation?

Answer 15

1. Moving up and down
2. Moving left and right
3. Moving forward and backward

Question 16

What are the degrees of rotation?

Answer 16

1. Tilting forward and backward (pitching)
2. Turning left and right (yawing)
3. Tilting side to side (rolling)

Question 17

What is a planar joint?

Answer 17

Joints between articular processes of cervical vertebrae

• few true planar joints
• certain joints in the carpus/tarsus

Question 18

What is a pivot joint?

Answer 18

1 DOF
Peg fitted within a ring - peg rotates about ring or vice versa
- proximal radioulnar joint - supination and pronation
- atlantoaxial joint

Question 19

What is a hinge joint?

Answer 19

1 DOF
One articular surface convex, the other is concave to receive it
Usually a notch to limit side to side motion
Pendular movement

Question 20

What is a condylar (condyloid/ellipsoidal) joint?

Answer 20

2 DOF
Ovid convex surfaces with corresponding concavity(ies)
Movements at right angles. Some rotation
Biaxial - many are primarily uniaxial especially where more than one condyle is present

Question 21

What is a saddle joint?

Answer 21

2 DOF

Two surfaces - convex in one direction; concave in the other at right angles to the first

Question 22

What is a ball and socket joint?

Answer 22

3 DOF

Versatile movement e.g., hip

Question 23

How do joint types relate to adaptable limb function?

Answer 23

• Increase range of motion
• Stabilise via joint shape
• Joint locking - energetic efficiency
• Moment arms
• Direction of joint rotation to suit gait/lifestyle