Articulations

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Articulations
The place of union or junction between two or
more bones of the skeleton (also between
cartilage and bones/teeth and bones - allow for
movement - structure of joint determines the
range of movement - the closer the fit, the
stronger the joint the looser the fit, the more
movement ARTHROLOGY The science concerned
with the study of joints, includes function,
structure, classification and any dysfunctions
KINESIOLOGY the science concerned with the
functional relationship, or biomechanics, of the
skeleton, joints and muscles as they work
together to produce coordinated movement.
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• Classification of joints
• A. Structural classification based on the
  presence or absence of a joint cavity and the
  kind of supportive tissue surrounding the joint.
• Three types
• 1. Fibrous joints lack a joint cavity fibrous
  connective tissue connects articulating joints
• 2. Cartilaginous joints lacks a joint cavity
  cartilage binds articulating bones
• 3. Synovial joints has a joint cavity
  ligaments help support articulating bones

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• B. Functional classification based on the
  degree of movement permitted within the joint
• Three types
• Synarthrosis immoveable joints
• Amphiarthrosis slightly moveable joints
• Diarthrosis freely moveable joints

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• II. Breakdown by functional classification
• Synarthroses (immoveable joints)
• 1.Suture strongest joint by structure
• - fibrous joints found between flat bones of the
  skull
• - irregular structure that gives strength and
  reduces fractures
• 2.Gomphoses
• - fibrous joints that occur between teeth and
  the supporting bones of the jaw.
• - located where the root of a tooth is attached
  to the periodontal ligament of the alveolus
  (socket) of the bone.

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3. Synchondroses - cartilaginous joint with
hyaline cartilage as the connective tissue - some
are temporary and form the epiphyseal growth
plates between the diaphysis and epiphysis in
the long bones of children
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• B. Amphiarthroses slightly moveable joint
• Syndesmoses
• Fibrous joint found only in the forearm and leg
  where adjacent bones are held together by
  collagenous fibers
• Characteristic of the side-to-side joints between
  tibia-fibula and the radius-ulna (allows
  rotation)
• 2. Symphyses (symphysis pubis, and intervertebral
  discs)
• Cartilaginous joint separated by a pad of
  fibrocartilage allows for limited movement
• Only limited motion is possible at each joint,
  the combined movement allows for extensive
  movement (vertebrae)

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• C. Diarthroses freely moveable
• Characteristics
• a. provides a wide range of precise, smooth
  movements while maintaining stability, strength,
  and some rigidity in the body
• b. most complex and varied of the three major
  types
• c. range of movement is limited by three
  factors

- structure of the bones participating in the
articulation - the strength and tautness of the
associated ligaments, tendons and joint capsule -
the size, arrangement and action of the muscles
that span the joint (double jointed is a
misnomer not two joints, but extreme
maneuverability due possibly to loose ligaments
and tendons)
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2. Structure of the synovial joint a. Synovial
Cavity space between the articulating bones
refers to the structural classification b.
Articular Cartilage present in all diarthrotic
joints (2 mm thick), hyaline cartilage covers the
articulating surface c. Articular Capsule
surrounds the entire diarthrotic joint (two
layers)
FIBROUS LAYER outer layer - dense, irregular
connective tissue - attaches to periosteum of
bones - permits movement and resists
dislocation - fibers from ligaments hold bones
together
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SYNOVIAL MEMBRANE Inner layer - secretes
synovial fluid (looks,feels like uncooked egg
white) - lubricates joints and nourishes
cartilage - houses phagocytic cells that remove
microbes and debris
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d. Accessory ligaments some outside of
articular capsule, some within

• e. Articular discs pads of fibrocartilage
  called menisci (meniscus singular)
• Stabilize joint by forming tighter fit
• Tearing of these is called torn cartilage

• f. Bursae sac-like structures between moving
  parts (help cushion and reduce friction
• Filled with synovial fluid
• Found between skin and bone, tendon and bone,
  muscle and bone, ligaments and bone

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3. Types of synovial joints

• Gliding joint simplest type
• - Allow only side-to-side and back-and-forth
  movements with minimal rotation
• Surfaces are usually flat or slightly
  concave/convex
• EX Intercarpal/intertarsal, sternoclavicular,
  between adjacent vertebrae

• b. Saddle joint- looks like a saddle
• Each articular process has a concave surface in
  one direction, convex in the other
• Is a modified condyloid joint allowing a wider
  range of movement
• EX only associated with the thumb (located at
  the articulation of the trapezium of the carpus
  with the first metacarpal bone)

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• c. Hinge joint permits bending in only one
  direction
• (similar to the hinge of a door)
• One surface is always concave and the other is
  convex
• Most common type of synovial joint
• EX knee, humeroulnar, phalanges

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• d. Pivot movement is limited to rotation about
  a central axis
• One surface is rounded and fits into a depression
  of another
• EX proximal articulation of the radius and ulna,
  articulation between atlas and axis

• e. Ball-and socket formed by articulation of a
  rounded convex surface with a cuplike cavity
• Provides the greatest range of movement of all
  joints
• EX hip and shoulder joints

f. Condyloid or ellipsoid structured so that an
oval, convex surface of one bone fits into an
elliptical, concave depression of another bone -
Allows for angular movement in two directions (up
and down and side-to-side motion) - EX
radiocarpal joint
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• III. Problems
• Clinical considerations
• 1. Hyperextension
• 2. Strained joint
• 3. Sprain
• 4. Luxation
• 5. Bursitis
• 6. Tendonitis

B. Diseases of joints Arthritis - 1.
Rheumatoid arthritis 2. Osteoarthritis
3. Gouty arthritis
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www.crnasomeday.com/anatpages/joints.htm
www.brazoria-county.com/sheriff/images/jpg/id...
www.mnsu.edu/.../humananatomy/images/body.jpg
healthcare.utah.edu/healthinfo/images/ei_0276.gif
commons.bcit.ca/.../pics/symphysis.jpg
cache.eb.com/eb/image?id72183rendTypeId35
images.main.uab.edu/healthsys/ei_0244.gif
content.answers.com/.../dental/f0475-01.jpg
www.hawaii.edu/.../pediatrics/pemxray/v1c18f.jpg
academic.wsc.edu/faculty/jatodd1/351/joints2.jpe
www.daviddarling.info/images/synovial_joint.jpg
cache.eb.com/eb/image?id72183rendTypeId35
sciencefun4all.net/.../Images/Joints/GLIDING.jpg
www.shockfamily.net/skeleton/SADDLE.JPG
www.mc.edu/.../carastafford2_files/image010.jpg
sciencefun4all.net/.../Images/Joints/HINGE.jpg