Classes and Subclasses of Joints

Question 1

Synarthroses (immovable):

Answer 1

1. synostoses: complete bone fusion (cranial sutures and repaired fractures)
2. synchondroses: surfaces joined by hyaline cartilage (ribs and epiphyseal growth plate)

Question 2

Amphiarthroses (slightly movable):

Answer 2

1. Symphyses: discs of fibrocartilage between 2 bones (pubis symphysis and intervertebral joints)
2. Syndesmoses: connected by ligaments alone (between radius and ulna; between tibia and fibula)

Question 3

Diathroses (freely movable):

Answer 3

1. fibrous capsule:
   
   • lined internally by synovial membrane
2. synovial fluid:
   
   • water with soluble proteins
   • provides nutrients for articular cartilage
   • reduces friction and heat buildup
3. articular cartilage:
   
   • thin layer of hyaline cartilage
   • provides smooth surface for articulation
4. Menisci:
   
   • semilunar, fibrocartilage discs
   • contains nerves for sensory reception
   • provides cushioning and joint stability
5. bursae:
   
   • extra articular sac of fluid
   • pad to improve muscle/tendon gliding