Lecture 5: Articulations & Axial Skeleton

Question 1

Articulations

Answer 1

-Locations where two or more bones meet
-Only points at which movements of bones can do occur
-Classifed based on
•Function (range of motion)
•Structure - how are the bones held together

Question 2

Structural classification of articulations

Answer 2

1. Bony- bones fused together
2. Fibrous- bones held together by fibrous connective tissue
3. Cartilaginous- bones held together by Cartilage
4. Synovial- complex arrangement of joint capsule, synovial membrane and fluid, and supporting tissues

Question 3

Synarthrosis

Answer 3

• No movement allowed

- Extremely strong

Question 4

Ampiarthrosis

Answer 4

• Little movement allowed
• Much stronger than diarthrosis
• Articulating bones connected by collagen fibers or cartilage

Question 5

Diarthrosis

Answer 5

• Synovial joints
• Freely moveable
• Least stable/ weakest type of articulation

Question 6

Glenohumeral

Answer 6

-The diarthrotic synovial articulation Between the glenoid cavity of the scapula and the head of the humerus

Question 7

Pubic symphysis

Answer 7

-The amphiarthrotic cartilaginous articulation Between the pubic bones of the os coxae

Question 8

Sagittal suture

Answer 8

-the synarthrotic fibrous articulation between the left and right parietal bones

Question 9

Types of synarthroses

Answer 9

-Sutures (2A)
•Bones interlocked with fibrous connective tissue
•Found between most bones of skull
-Gomphosis (2A)
•Another fibrous joint
•Found between teeth and bones of jaw (mandible, maxilla)
-Synchondrosis (3A)
•A cartilaginous articulation
• Ex: Epiphyseal plate, Cartilage of ribs at sternal ends
-Synostosis (1A)
• Bony fusion (3 coxal bones, frontal bones of infant)

Question 10

Types of Amphiarthroses

Answer 10

-Syndesmosis(2B)
• A fibrous articulation ligaments connect two bones but limit their motion (mid radioulnar, mid tibiofibular, coracoacromial, inferior tibiofibular)
-Symphysis (3B)
•A cartilaginous articulation, Bones separated by wedge or pad of fibrous Cartilage (pubic symphysis, intervertebral disk)

Question 11

Diarthroses (Freely moveable)

Answer 11

• All diarthroses are synovial joints
• Typically found at the ends of long bones
• Ex: elbow, knee, glenohumeral, sacroiliac

Question 12

Synovial joint structure

Answer 12

1. A joint capsule
2. Presence of articular cartilages
3. A joint cavity with synovial fluid
4. A synovial membrane
5. Accessory structures (Cartilage, ligaments, tendons, bursae sacs)
6. Sensory nerves and blood vessels

Question 13

Synovial fluid functions

Answer 13

• Lubricates the surfaces of the articular cartilages and reduces friction
• Nourishes the Chondrocytes by entering and exiting the articular cartilages due to the forces acting on the joint
• Acts as a shock absorber