L4: Joints

Question 1

What is the definition of joints؟

Answer 1

Articulation between two or more bones.

Question 2

What are Joints classified according to?

Answer 2

• According to the nature of tissue between the articulating bones
• According to mobility

Question 3

What are bones classified into according to the nature of tissue between the articulating bones?

Answer 3

 Fibrous.
 Cartilaginous.
 Synovial.

Question 4

What are joints classified into according to mobility?

Answer 4

 no mobility.
 Limited mobility.
 Freely mobile.

Question 5

What are the characteristics of fibrous joints (Synarthroses)?

Answer 5

 Articulating bones are separated by fibrous tissue.

 Produce no mobility.

Question 6

Compare between the types of fibrous joints

Answer 6

Question 7

What are the characteristics of cartilaginous joints (Amphiarthroses)?

Answer 7

 Bones are united by cartilage.

 Limited mobility.

Question 8

Compare between the types of cartilaginous joints

Answer 8

Question 9

What are the characteristics of synovial joints?

Answer 9

 Freely mobile joints.

 Characterized by presence of joint cavity.

 Articular surfaces are covered by hyaline cartilage.

 Bones are surrounded by fibrous capsule.

 Presence of synovial membrane and synovial fluid

Question 10

What the what is the synovial membrane line and what is its function?

Answer 10

 Lines the inner surface of capsule and covers non articular parts of bones.

 Its function is to produce and absorbe the synovial fluid.

Question 11

What are the functions of the synovial fluid?

Answer 11

1) Allow free mobility of joints.
2) Lubrication of articular cartilage.
3) Provides nutrition of articular cartilage and structures inside joint cavity.

Question 12

What are the structures inside joints?

Answer 12

Question 13

What are the types of synovial joints according to the number of axes?

Answer 13

1) No axis joints.
2) Uni-axial joints
3) Bi-axial joints.
4) Poly axial joints.

Question 14

What are the types of synovial joints according to the shape of articulating bones?

Answer 14

1) Plane joints.
2) Hinge joints.
3) Pivot joints
4) Saddle joints
5) Ellipsoid joints.
6) Ball & socket joint.

Question 15

What are uni-axial joints?

Answer 15

• Hinge joints (Ginglymus)

- Pivot joints (Trachoid)

Question 16

Hinge joints (Ginglymus)

Answer 16

Question 17

Pivot joints (Trachoid)

Answer 17

Question 18

What are bi-axial joints?

Answer 18

• Ellipsoid joints (Condyloid)

- Saddle joints (Sellar)

Question 19

Ellipsoid joints (Condyloid)

Answer 19

Question 20

Saddle joints (Sellar)

Answer 20

Question 21

What are poly-axial joints?

Answer 21

Ball and socket (spheroidal and cotyloid)

Question 22

Ball and socket (spheroidal and cotyloid)

Answer 22

Question 23

What are non-axial joints?

Answer 23

Plane joints

Question 24

Plane joints

Answer 24

Question 25

What are the factors that are responsible for stability and the strength of joints?

Answer 25

1) Shape of articulating bones. 2) Muscle around joints. 3) Ligaments related to joints.