Joints
I. Classification of joints according to movement
A. Synarthroses immovable joints
B. Amphiarthroses slightly moveable joints
C. Diarthroses freely moveable joints
II. Classification of joints according to structure
A. Fibrous joints have fibers that hold them together very tightly = synarthroses
B. Cartilagenous joints connected by cartilage which permits slight movement = amphiarthroses
C. Synovial joint have a synovial membrane surrounding bones that don't touch = diarthroses
III. Types of joints
A. Synarthroses
1. sutures between the bones of the skull
2. synchondroses have cartilage connections not fiberous. Metaphysis of long bone in children.
Joint between ribs 1-10 and the sternum.
3. gomphoses between the root of the tooth and the alveolar process of maxialla and mandible
B. Amphiarthroses
1. Symphyses where a pad of fibrocartilage connects two bones ie symphysis pubis
2. Syndesmoses lack cartilage. Are held together by interoseus ligaments. Fibula attached to tibia.
C. Diarthroses 6 characteristic structures of synovial joints
1. Joint capsule extension of periosteum
2. Synovial membrane lines inner surface of joint capsule, secretes synovial fluid
3. Articular cartilage thin layer of hyaline cartilage covering articulating surfaces of bones
4. joint cavity space between articulating bone ends.
5. menisci pads of fibrocartilage between articulating bones
6. ligaments strong cords of dense white fibrous tissue connecting two bones
IV. types of movement at diarthroses
A. Anguolar movements change in size of angle between bones
B. Flexion decrease in angle between bones
C. Extension increase in angle between bones
D. hyperflexion extending beyond anatomical position
E. Abduction movement away from midline
F. Adduction movement toward midline
G. Dorsiflexion flexing foot
H. plantar flexion pointing foot
I. inversion of foot toward midline
J. eversion of foot away from midline
K. Supination palm facing forward
L. Pronation palm facing backward
M. Rotation head side to side
N. Circumduction pitching
O. Protraction moves a part forward
P. Retraction Moves a part back
Q. Elevation moves a part upward
R. Depression moves a part backward
V. Types of Diarthrotic joints
A. Uniaxial joints movement occurs in one planes
1. hinge joint knee, elbow or phalanges
2. pivot joint axis with the atlas of vertebral column
B. Biaxial joints movement occurs in two planes
1. saddle joints thumb joint
2. condyloid joint radius with the wrist bones
C. multiaxial joints movement in three or more planes
1. ball and socket shoulder
2. gliding joints body of vertebrae
VI. Busae
A. small synovial fluid filled sacs found wherever pressure is exerted
1. between skin and bone
2. between tendons and bone
3. between muscle and bone
4. between ligaments and bone
B. Pathology
1. bursitis is the inflamation of these bursae in elbow, knee, shoulder etc.
V. Pathology of joints
A. Osteoarthritis
1. thinning articular cartilage
2. new bone forms at the margins
3. limitations to range of motion
B. Rheumatoid arthritis
1. inflammation of synovial membrane
2. granulation tissue forms on articular cartilages
3. this tissue can erode cartilage, bone or ligaments
C. Gouty arthritis
1. high levels of uric acid lead to sodium urate crystals in extracellular fluid
2. precipitate in synovial fluid
3. causes severe pain in joints