Chapter 9

  1. Structural classification—joints are named according to one of the following:
    • Type of connective tissue that joins bones together (fibrous or cartilaginous joints)
    • Presence of a fluid-filled joint capsule (synovial joint)
  2. Functional classification—joints are named according to degree of movement allowed:
    • •Synarthroses —immovable joint
    • •Amphiarthroses —slightly movable
    • •Diarthroses —freely movable
  3. Synarthroses (Fibrous joints)
    • bones of joints fit together closely, allowing little or no movement (Figure 9-1)
    • –Syndesmoses —joints in which ligaments connect two bones
    • –Sutures —found only in skull; toothlike projections from adjacent bones interlock with each other
    • –Gomphoses —between root of a tooth and the alveolar process of the mandible or maxilla
  4. Amphiarthroses (Cartilaginous joints)
    • bones of joints are joined together by hyaline cartilage or fibrocartilage; allow very little motion (Figure 9-2)
    • Synchondroses —hyaline cartilage present between articulating bones
    • Symphyses —joints in which a pad or disk of fibrocartilage connects two bones
  5. Synovial joints (diarthroses)—freely movable joints (Figure 9-3)
    • •Joint capsule —sleevelike casing around ends of bones, binding them together
    • •Synovial membrane —lines joint capsule and also secretes synovial fluid
    • •Articular cartilage— hyaline cartilage covering articular surfaces of bones
  6. Structures of synovial joints
    • • Joint cavity —small space between the articulating surfaces of the two bones of the joint
    • • Menisci (articular disks) —pads of fibrocartilage located between articulating bones
    • • Ligaments —strong cords of dense, white, fibrous tissue that hold bones of synovial joint more firmly together
    • • Bursae —synovial membranes filled with synovial fluid; cushion joints and facilitate movement of tendons
  7. Uniaxial joints
    synovial joints that permit movement around only one axis and in only one plane
  8. Hinge joints
    articulating ends of bones form a hinge-shaped unity that allows only flexion and extension ex. Elbow and knee joints
  9. Pivot joints
    a projection of one bone articulates with a ring or notch of another bone, ex. C1, C2 joint (dens of axis rotating against atlas) and head of radius and ulna
  10. Biaxial joints
    synovial joints that permit movements around two perpendicular axes in two perpendicular planes
  11. Saddle joints
    synovial joints in which the articulating ends of the bones resemble reciprocally shaped miniature saddles; only occurrence in body is in thumbs (carpo-metacarpal joint)
  12. Condyloid (ellipsoidal) joints
    synovial joints in which a condyle fits into an elliptical socket. Ex. Atlanto-occipital joint
  13. Multiaxial joints
    synovial joints that permit movements around three or more axes in three or more planes
  14. Ball and socket (spheroid) joints
    most movable joints; ball-shaped head of one bone fits into a concave depression. Ex. Shoulder and hip joints
  15. Gliding joints
    • relatively flat articulating surfaces that allow limited gliding movements along various axes.
    • ex. Facet joints between articular processes of vertebrae
  16. Humeroscapular joint (Figure 9-5)
    • Shoulder joint, a ball and socket joint
    • Multiaxial joint
    • Most mobile joint because of the shallowness of the glenoid cavity
  17. Glenoid labrum
    • narrow rim of fibrocartilage around glenoid cavity that lends depth to the cavity
    • Structures that strengthen the shoulder joint are ligaments, muscles, tendons, and bursae
  18. Humeroradial joint
    lateral articulation of capitulum of humerus with head of radius
  19. Humeroulnar joint
    medial articulation of trochlea of humerus with trochlear notch of ulna
  20. Proximal radioulnar joint
    • between head of radius and medial notch of ulna
    • –Stabilized by annular ligament
    • –Permits rotation of forearm
    • –Dislocation of radial head called “pulled elbow”
  21. Distal radioulnar joint
    • point of articulation between ulnar notch of radius and head of ulna
    • Together with proximal radioulnar joint, permits pronation and supination of forearm
  22. Radiocarpal (wrist) joints (Figure 9-7)
    • Only radius articulates directly with carpal bones distally (scaphoid and lunate)
    • –Joints are synovial
    • –Scaphoid bone is fractured frequently
    • –Portion of fractured scaphoid may become avascular
Card Set
Chapter 9