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Articulations ( Joints )
Contents:
1.
2.
3.
4.
5.
Introduction
Joint classification
Fibrous joint
Cartilaginous joint
Synovial joint
Types
Movements
6. Factors affecting range of motion
7. Aging and joints
8. Disorders
Rheumatism
Arthritis
Gout
1. Introduction:
-Joint (Articulation or arthrosis) is a point of contact
between two bones, between cartilage and bone or
between teeth and bones
-Arthrology: Science that deals the study of joints
2. Joint classification:
a. Structurally:
-Fibrous
-Cartilaginous
-Synovial
b. Functionally ( related to movements)
-Synarthroses ( immovable )
-Amphiarthroses ( partially movable )
- Diarthroses ( Freely movable )
3. Fibrous joint:
Joint where bones are held together by fibrous connective
tissue----permit very little or no movement
Types of fibrous joint:
i.
ii.
iii.
Sutures: Composed of a thin layer of fibrous
connective tissue that unites skull bone.
Syndesmoses: Joint with more fibrous connective
tissue: Joint of Tibia and Fibula
Gomphosis: Joint where a cone shaped peg fits into
a socket. Root of teeth in the socket
4. Cartilaginous joint:
- Articulating bones are connected by either
fibrocartilage or Hyaline cartilage –allows little
movement.
Types of Cartilaginous joint:
i.
ii.
Synchondrosis: Joint where connecting material is
hyaline cartilage. Epiphyseal plate connect diaphysis
with epiphysis
Symphysis: Where connecting material is a
fibrocartilage disc. Intervertebral disc & pubic
symphysis
5. Synovial joint:
- Must have synovial cavity between the
articulating bones and are freely movable
a. Structures:
i.
Articular cartilage
ii. Articular capsule: composed of outer fibrous
capsule and inner synovial membrane
iii. Accessory ligaments and articular disc
iv. Synovial fluid: secreted by synovial membrane.
b. Sprain and strain:
Sprain is forcible twisting causing stretch and tear of
ligaments but does not dislocate
Strain is a stretched or partially torn muscle
c. Types of synovial joint:
i.
ii.
iii.
iv.
v.
vi.
Planar joint: permit side to side movement.
Intercarpal, intertarsal joints
Hinge joint: Knee, elbow ankle joints
Pivot joint: round surface of one bone fits into ring
formed by another bone.Head of radius with radial
notch of ulna
Ellipsoidal/ Condyloid joint: Oval shaped condyle of
one bone fits into an elliptical cavity of another
bone. Carpal (Scaphoid) with radius
Saddle shaped joint: Carpal (Trapezium) with
metacarpal of the thumb
Ball-and-socket joint:Hip joint and shoulder joint
are good example.
d. Types of movement of synovial joint:
1. Gliding movement: Occur in planar joints
2. Angular movements: There is an increase or decrease
in the angle between the articulating bones. They are:
i.
ii.
iii.
iv.
Flexion: causes a decrease in the angle
Extension: results in an increase in the angle
Lateral flexion: causes movement of the trunk
sideways at the intervertebral joint
Hyperextension: Continuation of extension
beyond anatomical position of the joint
3. Other movements:
i.
ii.
iii.
Abduction: Movement away from midline
Adduction: movement towards midline
Circumduction: movement of the distal end of
a part of the body in a circle.
4. Special movements:
i.
ii.
iii.
Elevation: Upward movement
Depression: Downward movement
Protraction: Movement anteriorly in the
transverse plane
iv. Retraction: Protracted part back to anatomical
position
v.
Inversion: Movement of sole medially
vi. Eversion: Movement of sole laterally
vii. Dorsiflexion: Bending of the foot at ankle
towards the leg
viii. Planter flexion: Bending of the foot in the
direction of planter surface
ix.
x.
xi.
Supination: Palm is turned anteriorly
Pronation: Palm is turned posteriorly
Opposition: Movement of thumb across the
palm to touch the tips of all fingers in the same
hand
5. Disorders:
i.
Rheumatoid arthritis: Autoimmune disease.
Immune system attacks its own cartilage and
joint lining. Causes loss of joint function
ii.
Osteoarthritis: Degenerative joint disease—
called wear & tear arthritis. Affects weight
bearing joints
iii. Gouty arthritis: sodium crystals are deposited in
soft tissues of joints.