anatomy chapter 9 joints

  1. four major types of joints
    cartilaginous, fibrous, bony, synovial
  2. bony joint
    • synostosis; joint formed when the gap between two bones ossify, and they become in effect, a single bone
    • frontal and mandibular bones in infants
    • cranial sutures in elderly
    • attachment of first rib and sternum with old age

    can occur in either fibrous or cartilaginous joint
  3. fibrous joints
    • synarthrosis, or synarthrodialjoint –a point at which adjacent bones are bound by collagen fibers that emerge from one bone, cross the space between them, and penetrate into the other
    • Three kinds of fibrous joints–sutures–gomphoses–syndesmoses
  4. sutures
    • Sutures-immovable or slightly movable fibrous joints that closely bind the bones of the skull to each other
    • •Sutures can be classified as:
    • –serrate–interlocking wavy lines •coronal, sagittal and lambdoid sutures
    • –lap(squamous)-overlapping beveled edges •temporal and parietal bones
    • –plane(butt)-straight, nonoverlappingedges•palatine processes of the maxillae
  5. gomphoses
    • kind of fibrous joint
    • Gomphosis-attachment of a tooth to its socket
    • •Held in place by fibrous periodontal ligament–collagen fibers attach tooth to jawbone–allows the tooth to move a little under the stress of chewing
  6. syndesmosis
    • kind of fibrous joint
    • syndesmosis–longer collagenous fibers than in a suture or gomphosis
    • –More mobility–interosseusmembrane

    • •Most mobile syndesmosis–interosseusmembranes unite radius to ulna allowing supinationand pronation
    • •Least mobile syndesmosis–tibia to fibula
  7. cartilaginous joint & two types
    • amphiarthrosis or amphiarthrodialjoint–two bones are linked by cartilage
    • •Two types of cartilaginous joints–synchondroses–symphyses
  8. Synchondrosis
    • Synchrondrosis-bones are bound by hyaline cartilage
    • –temporary joint in the epiphysealplate in children
    • •binds epiphysis and diaphysis
    • –first rib attachment to sternum
    • •other costal cartilages are joined to sternum by synovial joints
  9. symphysis
    • Symphysis-two bones joined by fibrocartilage
    • –pubic symphysis in which right and left pubic bones joined by interpubicdisc
    • –bodies of vertebrae and intervertebraldiscs•only slight amount of movement between adjacent vertebrae•collective effect of all 23 discs gives spine considerable flexibilityPubic
  10. Synovial joint
    • diarthrosis or diarthrodial joint
    • –joint in which two bones are separated by a space called a joint cavity
    • •Most familiar type of joint; Most are freely movable; Most structurally complex type of joint; Most likely to develop painful dysfunction; Most important joints for physical and occupational therapists, athletic coaches, nurses, and fitness trainers
  11. articular cartilage
    layer of hyaline cartilage that covers the facing surfaces of two bones–usually 2 or 3 mm thick
  12. Synovial fluid
    • –slippery lubricant in joint cavity
    • –rich in albumin and hyaluronicacid
    • –gives it a viscous, slippery texture like raw egg whites
    • –nourishes articularcartilage and removes waste
    • –makes movement of synovial joints almost friction free
  13. Joint (articular) capsule
    • –connective tissue that encloses the cavity and retains the fluid–outer fibrous capsule
    • –continuous with periosteumof adjoining bones
    • –inner, cellular, synovial membrane-composed mainly of fibroblast-like cells that secrete synovial fluid and macrophagesthat remove debris from the joint cavity
  14. fibrocartilage
    In a few synovial joints,fibrocartilagegrows inward from the joint capsule
  15. articular disc
    • forms a pad between articulating bones that crosses the entire joint capsule
    • •temporomandibular joint, distal radioulnar joints, sternoclavicular and acromioclavicular joints
  16. meniscus
    • in the knee, two cartilages extend inward from the left and right but do not entirely cross the joint
    • •these cartilages absorb shock and pressure•guide bones across each other
    • •improve the fit between bones•stabilize the joints, reducing the chance of dislocation
  17. tendon
    • a strip or sheet of tough collagenousconnective tissue that attaches muscle to bone
    • •the most important structures in stabilizing a joint
  18. ligament
    similar tissue that attaches one bone to another
  19. bursa
    • a fibrous sac filled with synovial fluid, located between adjacent muscles, where tendon passes over bone, or between bone and skin
    • •cushion muscles, helps tendons slide more easily over joints, modify direction of tendon pull
  20. tendon sheaths
    • elongated cylindrical bursae wrapped around a tendon
    • •in hand and foot
  21. Mechanical Advantage
    calculated from the length of the effort arm divided by the length of the resistance arm•MA > 1.0 –the lever produces more force, but less speed and distance, than the force exerted on it•MA < 1.0 –the lever produces more speed or distance, but less force, than the input
  22. first class lever
    • Has fulcrum in the middle between effort and resistance (RFE)
    • •Atlanto-occipital joint lies between the muscles on the back of the neck and the weight of the face
    • –loss of muscle tone occurs when you nod off in class
  23. Second class levers
    • Resistance between fulcrum and effort (FRE)
    • •Resistance from the muscle tone of the temporalismuscle lies between the jaw joint and the pull of the digastricmuscle on the chin as it opens the mouth quicklyE
  24. third class levers
    • Effort between the resistance and the fulcrum (REF)
    • –most joints of the body
    • •The effort applied by the biceps muscle is applied to the forearm between the elbow joint and the weight of the hand and the forearm
  25. classes of synovial joints
    ball and socket, hinge, pivot, plane, saddle, condylar
  26. ball and socket joints
    • Smooth, hemispherical head fits within a cuplike socket
    • –shoulder joint -head of humerus into glenoid cavity of scapula
    • –hip joint -head of femur into acetabulumof hip bone
    • •The only multiaxialjoints in the body
  27. condyloid joints
    • (ellipsoid joints)
    • Oval convex surface on one bone fits into a complementary shaped depression on the other
    • – radiocarpal joint of the wrist
    • –metacarpophalangeal joints at the bases of the fingers
    • •Biaxial joints –movement in two planes
  28. saddle joints
    • Both bones have an articular surface that is shaped like a saddle, concave in one direction and convex in the other
    • –trapeziometacarpal joint at the base of the thumb
    • –sternoclavicularjoint –clavicle articulates with sternum
    • •Biaxial joint–more movable than a condyloidor hinge joint forming the primate opposable thumb
  29. plane joints
    • (gliding joints)
    • Flat articular surfaces in which bones slide over each other with relatively limited movement
    • •Usually biaxial joint–carpal bones of wrist–tarsal bones of ankle–articular processes of vertebrae
    • •Although any one joint moves only slightly, the combined action of the many joints in wrist, ankle, and vertebral column allows for considerable movement
  30. hinge joints
    • One bone with convex surface that fits into a concave depression on other bone
    • –elbow joint -ulna and humerus
    • –knee joint -femur and tibia
    • –finger and toe joints
    • •Monoaxialjoint –move freely in one plane
  31. pivot joints
    • One bone has a projection that is held in place by a ring-like ligament
    • •Bone spins on its longitudinal axis–atlantoaxialjoint (dens of axis and atlas)
    • •transverse ligament–proximal radioulnarjoint allows the radius to rotate during pronationand supination
    • •anular ligament
    • •Monoaxial joint
  32. flexion
    • movement that decreases the a joint angle
    • –common in hinge joints
  33. extension
    movement that straightens a joint and generally returns a body part to the zero position
  34. hyperextension
    further extension of a joint beyond the zero position–flexion and extension occur at nearly all diarthroses, hyperextension is limited to a few
  35. abduction; hyperabduction
    movement of a body part in the frontal plane away from the midline of the body

    –hyperabduction–raise arm over back or front of head
  36. adduction; hyperadduction
    movement in the frontal plane back toward the midline

    –hyperadduction–crossing fingers, crossing ankles
  37. elevation
    a movement that raises a body part vertically in the frontal plane
  38. depression
    lowers a body part in the same plane
  39. protraction
    the anterior movement of a body part in the transverse (horizontal) plane
  40. retraction
    posterior movement
  41. circumduction
    • one end of an appendage remains stationary while the other end makes a circular motion
    • •Sequence of flexion, abduction, extension and adduction movements
    • –baseball player winding up for a pitch
  42. rotation
    movement in which a bone spins on its longitudinal axis–rotation of trunk, thigh, head or arm
  43. medial (internal) rotation
    turns the bone inwards
  44. lateral (external) rotation
    turns the bone outwards
  45. lateral excursion
    right or left movement from the zero position
  46. medial excursion
    movement back to the median, zero position–side-to-side grinding during chewing
  47. Ulnar flexion
    tilt hand towards little finger
  48. Radial flexion
    tilts hand toward the thumb
  49. Flexion of fingers
    curling fingers
  50. Extension of fingers
    straightening them
  51. abduction of fingers
    spread them apart
  52. adduction of fingers
    bring fingers back together
  53. flexion of thumb
    tip of thumb directed toward palm
  54. extension of thumb
    straightening the thumb
  55. radial abduction
    move thumb away from index finger 90°
  56. Palmar abduction
    moves thumb away from hand and points it anteriorly
  57. adduction of thumb
    moves it to the zero position
  58. opposition
    move the thumb to touch the tips of any of the fingers
  59. reposition
    return the thumb to the zero position
  60. dorsiflexion
    elevation of the toes as you do while swinging the foot forward to take a step (heel strike)
  61. Plantar flexion
    extension of the foot so that the toes point downward as in standing on tiptoe (toe-off)
  62. inversion
    a movement in which the soles are turned medially
  63. eversion
    a movement in which the soles are turned laterally
  64. supination of foot
    complex combination of plantar flexion, inversion, and adduction
  65. pronation of foot
    complex combination of dorsiflexion, eversion, and abduction
  66. STUDY
    • pages 14-21 of notes
    • TMJ, shoulder, hip, elbow, knee, ankle, arthritis, prosthetics
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anatomy chapter 9 joints
anatomy chapter 9 joints