Lecture 6- Joints

Question 1

Define joint or articulation

Answer 1

Site were two or more bones meet

Question 2

What are the 2 functions of joints

Answer 2

• gives skeleton mobility

- holds skeleton together

Question 3

What are the 3 classifications of joints, what are their distinguishing features and give examples for each

Answer 3

1. Synarthroses (immovable): fibrous joints
   -bones joined by dense fibrous connective tissue
   -no joint cavity
   3 types:
   A) sutures: skull
   B) syndesmoses: distal tibiofibular joint
   C) Gomphoses (teeth)
2. Amphiarthroses: slightly movable: cartilaginous joints.
   -bones united by cartilage, no joint cavity, 2 types
   A) synchondroses: chondro =cartilage….a bar or plate of hyaline cartilage unites the bones) eg joint between 1st rib and sternum
   B) symphyses: hyaline cartilage covers the articulating surfaces and is fused to an intervening pad of fibrocartilage. Eg pubic symphysis, or intervertebral discs,
3. Diarthrosis: synovial joint
   -synovial/ joint cavity
   -joint capsule: outer fibrous capsule of dense irregular connective tissue, and inner synovial membrane of loose connective tissue

Question 4

What are the distinguishing features of a synovial joint

Answer 4

• joint cavity
• articular cartilage: hyaline cartilage
• joint capsule: outer fibrous capsule of dense irregular connective tissue, and inner synovial membrane of loose connective tissue.
• synovial fluid: lubricates and nourishes articular cartilage.
• has rich nerve and blood vessel supply
• capillary beds produce the filtrate for synovial fluid
• bursae: flattened fibrous sacs lined with synovial membrane containing synovial fluid.

Question 5

What are the movements that occur along the Sagittal plane?

Answer 5

• flexing
• extension
• hyper extension

Question 6

What are the movements that occur along the frontal plane?

Answer 6

• abduction
• adduction
• circumduction

Question 7

What is protraction and retraction

Elevation and depression

Answer 7

1. Protraction eg jaw jutting outwards (anterior movement)
2. Retraction eg jaw coming inwards (posterior movement)
3. Elevation eg lifting a body part superiorly
4. Depression eg jaw moving downwards (moving a body part inferiorly)

Question 8

What are the 6 types of synovial joints based on shape of articular surfaces?

Answer 8

1. Plane
2. Hinge
3. Pivot
4. Condyloid
5. Saddle
6. Ball and socket
   Refer to anatomy book for pictures and examples

Question 9

Knee joint

What are the 3 joints which are surrounded by the joint cavity

Answer 9

1. Femoropatellar joint (allows gliding motion during knee flexion
2. lateral and medial tibiofemoral joints between the femoral condyles and the C shaped lateral and medial menisci (semilunar cartilages) of the tibia
   - allows flexion and extension and some rotation when knee is partly flexed
   - the joints capsule is reinforced by muscle tendons eg quads and semi membranous tendons

Question 10

What are the four rotator cuff tendons encircle the shoulder joint

Answer 10

Subscapularis
Supraspinatus
Infraspinatus
Terres minor