JOINTS
Fibrous Joints
•
•
•
•
•
•
Composed of articulating bones joined by dense collagen fibers
Little elasticity
Allow no empty spaces between surfaces
Fibrous connective tissue forms union of irregular bones along full common
borders
Allows no movement and called synarthrosis
Three types of fibrous joints: suture; syndesmosis; and gomphosis
o Suture example: bones of cranium in adult, no movement
o Syndesmosis example: interosseous ligament between tibia and fibula,
slight movement
o Gomphosis example: root of tooth attaches to jaw, no movement
Cartilaginous Joints
•
•
•
•
•
•
•
Cartilage is tissue also made of collagen
Similar to bone and fibrous tissue but lacks calcium
No blood or nutrient supply to cartilage
Flexible and strong and good shock absorber
Three types of cartilage: hyaline; elastic; and fibrocartilage
Two types of cartilaginous joints: synchondrosis and symphysis
There are no empty spaces between surfaces of cartilaginous joints
Synchondroses
•
•
•
•
A cartilaginous joint during youthful years that absorbs calcium in adulthood and
loses flexibility
Epiphysial plate is an example
Bwtween first rib and sternum and between manubrium and body of sternum
Once complete is immovable or synarthrotic
Symphyses
•
•
•
Primarily made of cartilage but has greater elasticity and flexibility than
synchondrosis
Example: pubic symphysis; articulation of vertebral body with one above/below
A slight degree of movement is allowed called amphiarthrotic or amphiarthrosis
Synovial Joints
•
•
•
•
•
•
•
Most common type in body
Freely movable
Examples: shoulder, hip, knee etc.
Called diarthrosis or diarthrotic joint movement
Six types responsible for specific functional movement
Movements occur on three planes; the number of planes a joint moves on is the
degree of movement or freedom
Elements allow movement and simultaneous joint integrity and stability:
o Articular cartilage; synovial cavity; joint capsule; synovial membrane;
synovial fluid and ligaments
Articular cartilage is hyaline; covers ends of bones for smooth slick surface; shock
absorber
Joint cavity is empty space between two bones to allow movement
Joint capsule is enclosed sac that surrounds all other structures of the joint
• Made of fibrous connective tissue and attaches to periosteum
Synovial membrane is thin inner lining of joint capsule
• Covers everything but areas of articular cartilage
• Made of loose connective tissue with blood supply and creates synovial fluid for
lubrication and sources of food and healing
Ligaments help hold joint together with joint capsule
• Some ligaments are inside joint capsule, others outside
• No blood supply so poor healing potential
Other elements not found in all synovial joints include:
• Meniscus
• Bursa
• Tendon sheaths
• Labrum
• Muscle