Joints

1
Joints

• AKA articulations functional junctions
  between bones
• Functions
• Bind parts of the skeletal system
• Make bone growth possible
• Permit parts of the skeleton to change shape
  during childbirth
• Enable the body to move in response to skeletal
  muscle contractions

2
Types of Joints

• Fibrous joints
• Cartilaginous joints
• Synovial joints
• Ball-and-socket joints
• Condyloid joint
• Gliding joints
• Hinge joint
• Pivot joint
• Saddle joint

3
Fibrous Joints

• Between bones that closely contact each other
• Bones are joined by thin layer of dense
  connective tissue
• No big movement at these joints
• Where do you think they would be found?

4
Cartilaginous Joints

• Bones connected by hyaline cartilage
  (fibrocartilage)
• Limited movement
• Examples intervertebral discs, symphysis pubis,
  rib 1 at the sternum

5
Synovial Joint

• Free movement
• Articular ends of bones are covered with hyaline
  cartilage (articular cartilage).
• Bones are held together with a surrounding,
  tubular capsule (joint capsule) of dense
  connective tissue.
• Outer layer of ligaments
• Inner lining of synovial membrane, which secretes
  synovial fluid that lubricates the joint

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Synovial Joint, continued..

• Some contain shock-absorbing pads of
  fibrocartilage, called menisci (meniscus, sing.)
  between articulating surfaces.
• Some have bursae, fluid-filled sacs which are
  lined with synovial membranes. (Bursae are
  commonly located between the skin and the
  underlying bony prominence.)

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Types of Synovial Joints

• Ball-and-socket joint --- allows for widest range
  of motion (Examples????)
• Condyloid joint
• oval-shaped condyle of one bone fits into
  elliptical cavity of another
• No rotation movement
• EX b/t phalanges and metacarpals
• Gliding joint
• Articulating surfaces are nearly flat
• Allow sliding and twisting movement
• EX carpals and tarsals

8
Types of Synovial Joints, continued..

• 4. Hinge joint
• Convex surface of one joint fits into concave
  surface of another
• Resembles hinged door, allowing movement in one
  plane only
• Examples ?????

9
Types of Synovial Joints, continued..

• 5. Pivot joint
• Cylindrical surface of one bone rotates within
  ring formed of bone and ligament
• Movement is only rotation around a central axis
• Example Joint b/t proximal ends of radius and
  ulna

10

• 6. Saddle joint
• Between bones with both convex and concave
  regions
• Allows for variety of movement
• Example Joint b/t metacarpal and carpal of thumb
• Which metacarpal is this?
• What is the name of this carpal bone????

11
Types of Joint Movement

1. Flexion bending
2. Extension straightening
3. Dorsiflexion bending foot toward shin
4. Plantar flexion bending foot toward sole
5. Hyperextension extension BEYOND anatomical
   position
6. Abduction away from midline of body
7. Adduction moving a part toward midline

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Types of Joint Movement, continued..

• 8. Rotation moving around an axis
• 9. Circumduction moving a part so its END
  follows a circular path
• 10. Pronation turning hand posteriorly
• 11. Supination turning hand anteriorly
• 12. Eversion turning foot so sole faces
  laterally
• 13. Inversion turning sole medially
• 14. Retraction moving a part backward
• 15. Protraction moving a part forward

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Types of Joint Movement, continued..

• 16. Elevation raising a part
• 17. Depression lowering a part