Joints

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Joints

• A joint is the site of meeting of two or more
  bones.
• Joints are classified into three types (depending
  on the material that hold the articular bones
  together)

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Fibrous joints

• Sutures only seen in between the skull bones and
  they frequently ossify with age).
• Syndesmosis
• Inferior tibiofibular joint (no movement in this
  joints and never ossify).
• Interosseous membrane connecting bones of forearm
  leg.
• Gomphosis in the joints between the teeth and
  jaws. Each tooth is connected to the socket by
  periodontal membrane.

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Cartilaginous joints

• Primary cartilaginous these are temporary
  joints, in which the bones are connected by
  hyaline cartilage that ossifies with age. No
  movement is possible. This type is seen in
• Epiphyseal plate connecting epiphysis and
  metaphysis.
• 1st sternocostal joint between 1st costal
  cartilage and sternum.

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Cartilaginous joints

• Secondary cartilaginous the bones are connected
  by disc of fibrocartilage, which rarely ossifies
  with age. A small amount of movement is possible.
  These joints are seen in the joints of midline of
  body
• Intervertebral discs
• Symphysis pubis
• Manubriosternal junction

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Synovial joints

• are held together by fibrous capsule
  characterized by presence of joint cavity.
  Synovial joints are freely movable and represent
  most joints of the body.
• The capsule is lined by synovial membrane that
  secretes lubricating fluid (synovial fluid) for
  the articular surfaces.
• Articular ends are covered by hyaline cartilage.
• The capsule is thickened in certain parts to form
  ligaments, which provide strength and flexibility
  to the joint.

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Synovial Joints

• Allow considerable movement
• Most joints that unite bones of axial and
  peripheral skeleton
• Articular cartilage and disks
• Joint cavity and capsule
• Synovial membrane and fluid
• Bursae

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Types of synovial joints
Type Variety Shape Movement Example
Plane Plane flat articulating surfaces allow gliding or sliding movement Acromio-clavicular J. Intercarpal js. Intertarsal js..
Uniaxial (allow movement around one axis only) Hinge - concave surface with convex surface - movement occurs around transverse axis - flexion extension Elbow J. Inter-phalangeal Js.
Uniaxial (allow movement around one axis only) Pivot - bony pivot surrounded by a ring - movement occurs around vertical axis - pronation supination - rotation Radioulnar Js. Atlantoaxial Js.
Biaxial (allow movements around two axis) Ellipsoid - oval convex surface fits into an ellipsoid concavity - movement occurs around 2 axes perpendicular to each other - flexion extension - abduction adduction Wrist J. Metacarpo-phalangeal Js.
Biaxial (allow movements around two axis) Saddle - both articular surfaces are concavo-convex - movement in 2 axes like ellipsoid J. with slight rotation - flexion extension - abduction adduction - slight rotation Carpo-metacarpal J. of thumb
Multiaxial (allow move-ment around multiple axes) Ball socket head of one bone fits into a cup-like concavity of other bone circumduction Shoulder J. Hip J.
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Types of Movement

• Angular
• Flexion and Extension
• Abduction and Adduction
• Circular
• Rotation
• Circumduction

Flexion and Extension
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Abduction and Adduction
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Rotation and Pronation and Supination
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Circumduction
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Special Movements

• Unique to only one or two joints
• Types
• Elevation and Depression
• Protraction and Retraction

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Elevation and Depression
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Protraction and Retraction
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Points to Remember

• A joint or articulation is a meeting between two
  bones and does not necessarily imply movement
• A joint can be classified according to its
  structure
• Synovial joints are the most complex
• Specific terms are used to describe the movements
  of joints that are freely movable.
• Commonly grouped in opposing pairs that move a
  part of the body in relation to the anatomical
  position.