Topic 1.1: Synovial Joints

Question 1

What is a joint?

Answer 1

A joint occurs when two or more bones articulate

Question 2

What types of joints are there?

Answer 2

1. Synovial
2. Cartilaginous
3. Fiberious

Question 3

Synovial Joint

Answer 3

• Most commonly occured joints
• Free movement in one or more planes
• Most important for motility

Question 4

Fiberous joint

Answer 4

• Thin layer of fibrous tissue connecting the edges of two bones
• Continuous with periosteum
• No movement allowed at these joints

Question 5

Cartilaginous joint

Answer 5

• Bones seperated by fibrocartilage disc or thick layer of hyaline cartilage
• Limited movement allowed

Question 6

Structure of a synovial joint

Answer 6

Question 7

What are the 6 types of synovial joint?

Answer 7

1. Hinge
2. Pivot
3. Ball & Socket
4. Condyloid
5. Saddle
6. Plane

Question 8

Hinge joint

Answer 8

• Allows movement on only 1 axis
• Allows FLEXION and EXTENSION
• For example: a door can only open and close/ elbow joint

Question 8

Pivot joint

Answer 8

• Only allow rotation
• Rotates along the long axis
• Have a ring of bone that fits over a bone protrusion, around which it can rotate
• Pronation and Supination
• For example:
• During pronation, the radius rotates over the ulna

Question 9

Ball & Socket joint

Answer 9

• Rounded end of one bone fits inside a cup-shaped ending on another bone
• Allows to move in all axis
• Most mobile joint
• Flexion/Extension, Abduction/Adduction, Rotation/Circumduction
• Example = Shoulder and hip joint

Question 9

Condyloid joint

Answer 9

• Similar to “Ball & Socket”, but instead of a round head, it is oval
• Can only rotate on 2 axis
• Flexion/Extension, Abduction/Adduction, Circumduction
• The oval head can also slides inside the socket
• Example = Wrist joint/Radiocarpal joint

Question 9

Saddle joint

Answer 9

• Similar to Condyloid joint
• Both bone has a concave and convex surface
• Convex = surface sticks out, like a hill
• Concave = surface curves in, like a hole or a cave
• The concave plane of one, fit onto the convex plane of the other
• Flexion/Extension, Adduction/Abduction, Circumduction, and very slightly rotation
• Example = Thumb joint

Question 9

Plane joint

Answer 9

• Two flat surface, one on top of another
• Can glide or rotate
• Often comes in group and ligaments hold the bones together
• Example = Carpals on the hand

Question 10

Whats in the Synovial Joint?

Answer 10

• Synovial (joint) cavity
• Bursa
• Joint (articular) capsule
• Synovial (membrane) lining
• Ligament
• Articular cartilage
• Synovial fluid

Question 11

Synovial (joint) cavity

Answer 11

• Space between the bone
• Contains synovial fluid

Question 12

Bursa

Answer 12

• Small fluid-filled sacs found in areas of high stress
• Found where two stuctures rub against eachother e.g. ligament and bone, tendon and bone
• Lined by synovial membrane which provide lubrication thereby reducing friction

Question 13

Joint (articular) capsule

Answer 13

• Flexible to allow joint movement to take place
• Tensile strength prevents joint from dislocation

Question 14

Synovial (membrane) lining

Answer 14

Secretes synovial fluid

Question 15

Ligament

Answer 15

• bind bone to bone
• Can snap easier than tendon - not very elastic
• Strong enough to stop movement outside the normal range

Question 16

Articular cartilage

Answer 16

• A smooth white layer that covers the end of bone
• Reduces friction, absorbs shock and protects bone
• Thickness depends on the amount of stress its exposed to

Question 17

Synovial Fluid

Answer 17

• Viscous fluid with the consistency and color of an uncooked egg whites
• Becomes more fluid with movement
• Lubricates joint cavity thereby reducing movement
• Provides nutrients to cartilage

Question 18

Bone Structure

Answer 18

• Articular cartilage
• Synovial membrane
• Synovial fluid
• Bursae
• Meniscus
• Ligaments
• Articular capsule

Question 19

Tendon

Answer 19

• Tendons bind muscle to bone
• Elastic
• Pulls on the bone