Joints and muscles

Question 1

Name the 3 types of joints and give 2 examples of each

Answer 1

Fibrous

a) skull (sutures)
b) outside skull (syndesmoses) eg. inferior tibulo-fibular joint

Cartilaginous

a) hyaline/synchondrosis eg. epiphesial plate of the radius
b) white fibrocartilage/symphysis eg. pubic symphysis and between vertebral bodies

Synovial

a) knee (hinge joint)
b) hip (ball and socket)

Question 2

What are syndesmoses?

Answer 2

A fibrous joints outside of the skull

Question 3

Explain the difference between synchondroses and symphyses.

Answer 3

Synchondrosis:

• hyaline cartilage
• growth mechanism (at the end of growth it becomes a synostosis)
• no movement
• replaced by bone (last to disappear ~ 25y/o)

Symphysis:

• a joint where WFC is the connecting substance, though there is a thin layer of hyaline covering bone surface
• small degree of movement

Question 4

Where in the body would you find fibrous joints acting as a growth mechanism?

Answer 4

The skull

Question 5

What are the key features of a synovial joint. Outline their function.

Answer 5

• Articular cartilage (hyaline cartilage lines articulating bones to provide smooth surfaces)
• Synovial membrane (produces synovial fluid)
• Synovial fluid (minimises friction)
• Fibrous capsule (stabilises joint)
• Ligaments (stabilise joint)
• Bursae (sack of synovial fluid allows lubrication/movement between joint and surrounding muscle)

Question 6

Do synovial joints have perichondrium?

Answer 6

No

Question 7

What are some additional features of synovial joints?

Answer 7

• Intra-articular discs/menisci (aids movement between incongruent surfaces, involves white fibrocartilage and synovial fluid)
• fat pads (outside of synovial membrane, not in weight bearing joints)
• ligaments
• tendons

Question 8

What structure produces synovial fluid?

Answer 8

Synovial membrane

Question 9

What are “adventitious bursae”?

Answer 9

Adventitious bursae develop at any site where soft tissues are subject to excess shearing stress. ie they develop after birth vs synovial bursae which develop in the embryo.

Question 10

How would you describe a synovial joint?

Answer 10

A joint with a cavity

Question 11

Which type of joint allows movement?

Answer 11

Synovial

Symphyses allow slight deformability but not as much movement as synovial.

Question 12

Name 3 sutures

Answer 12

1. Coronal
2. Sagittal
3. Lambdoid

Question 13

What are bursae?

Answer 13

A connective tissue sac with a synovial lining, which are usually present to counter friction at synovial joints