1. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings C h a p t e r 9 Articulations PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

2. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings An Introduction to Articulations  Articulations  Body movement occurs at joints (articulations) where two bones connect  Joint Structure  Determines direction and distance of movement (range of motion)  Joint strength decreases as mobility increases

3. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Classification of Joints  Two methods of classification  Functional classification is based on range of motion of the joint  Structural classification relies on the anatomical organization of the joint

4. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Functional Classifications Synarthrosis (immovable joint)  No movement and very strong  Fibrous or cartilaginous connections  May fuse over time  Four types: –1. Suture – located between the bones of the skull. –2. Gomphosis – bind the teeth to bony sockets –3. Synchondrosis – rigid, cartilaginous bridge between two articulating bones. Ex) epiphyseal cartilage –4. Synostosis – totally rigid, immovable joint created when two bones fuse and the boundary between them disappears ex) epiphyseal lines of mature long bones

5. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Functional Classifications  Amphiarthrosis (slightly movable joint)  Little movement  Stronger than freely movable joints  Fibrous or cartilaginous connections  Two types:  1. syndesmosis – bones are connected by a ligament –ex) distal articulation between the tibia and fibula  2. symphysis – bones separated by fibrous cartilage –ex) articulation between the bodies of vertebrae and the connection between the two pubic bones

6. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Functional Classifications  Diarthrosis (freely movable joint)  More movement  Also called synovial joints  Located at the ends of long bones  Subdivided by type of motion  A synovial joint is surrounded by a fibrous articular capsule and a synovial membrane that lines the walls of the articular cavity. The membrane does not cover the articulating surfaces within the joint.

7. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  Components of Synovial Joints  Articular cartilages  Pad articulating surfaces within articular capsules: –prevent bones from touching  Smooth surfaces lubricated by synovial fluid: –reduce friction  Normal synovial joint function cannot continue if this cartilage is damaged.

8. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  Components of Synovial Joints  Synovial fluid  Clear viscous solution with consistency of molasses  Functions of synovial fluid: –lubrication –nutrient distribution –shock absorption

9. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  Components of Synovial Joints  Accessory structures  Cartilages: –cushion the joint: »Fibrous cartilage pad called a meniscus (articular disc)  Fat pads: –superficial to the joint capsule –protect articular cartilages – packing material to fill in the spaces created as the joint cavity change shape when you move.

10. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  Ligaments: –support, strengthen joints –sprain: when a ligament is stretched to the point at which some of the collagen fibers are torn, but the ligament survives and the joint is not damaged.  Tendons: –attach to muscles around joint –help support joint  Bursae: –pockets of synovial fluid –They form where a tendon or ligament rub against other tissues to reduce friction and act as shock absorbers

11. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints [INSERT FIG. 9.1a] Figure 9–1a The Structure of a Synovial Joint.

12. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints Figure 9–1b The Structure of a Synovial Joint.

13. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  A joint cannot be both highly mobile and very strong. The greater the range of motion at a joint, the weaker it becomes.  Prevent injury by limiting range of motion  The collagen fibers of the joint capsule and any accessory or extrinsic ligaments  The shapes of the articulating surfaces and menisci, which may prevent movement in specific directions  The presence of other bones, skeletal muscles, or fat pads around the joint  Tension in tendons attached to the articulating bones

14. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Synovial Joints  Injuries  Dislocation (luxation)  Articulating surfaces forced out of position  Damages articular cartilage, ligaments, joint capsule  Subluxation  A partial dislocation

15. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Types of Movements at Synovial Joints  Linear, angular, rotation  Linear motion  Also called gliding  Two surfaces slide past each other: –between carpal or tarsal bones

16. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Angular Motion  Tip remains stationary but shaft changes angle relative to surface  Flexion –Anterior–posterior plane –Reduces angle between elements –Flexing your bicep  Extension –Anterior–posterior plane –Increases angle between elements –Extending arm  Hyperextension –Extension past anatomical position –Holding head back

17. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Angular Motion  Abduction  Frontal plane  Moves away from longitudinal axis  Stretching fingers out  Adduction  Angular motion  Frontal plane  Moves toward longitudinal axis  Bringing fingers together

18. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Angular Motion  Circumduction  Circular motion without rotation  Moving arm in loop

19. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements Rotation  Direction of rotation from anatomical position  Relative to longitudinal axis of body  Left or right rotation –Medial rotation (inward rotation): »rotates toward axis –Lateral rotation (outward rotation): »rotates away from axis

20. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Types of Movements at Synovial Joints  Rotation  Pronation: –rotates forearm, radius over ulna –Palm facing down  Supination: –forearm in anatomical position –Palm facing up

21. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Types of Movements at Synovial Joints  Special movements  Inversion: –twists sole of foot medially  Eversion: –twists sole of foot laterally  Dorsiflexion: –flexion at ankle (lifting toes)  Plantar flexion: –extension at ankle (pointing toes)

22. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Special Movements at Synovial Joints  Opposition  Thumb movement toward fingers or palm (grasping)  Protraction  Moves anteriorly  In the horizontal plane (pushing forward)  Ex) pushing jaw forward  Retraction  Opposite of protraction  Moving anteriorly (pulling back)

23. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Special Movements at Synovial Joints  Elevation  Moves in superior direction (up)  Ex) closing your mouth  Depression  Moves in inferior direction (down)  Ex) opening the moth  Lateral flexion  Bends vertebral column from side to side

24. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements Figure 9–5 Special Movements.

25. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements Figure 9–5 Special Movements.

26. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Classification of Synovial Joints by Shape  Gliding  Hinge  Pivot  Ellipsoid  Saddle  Ball-and-socket

27. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Gliding Joints  Flattened or slightly curved faces  Limited motion - side-to-side or back-and-forth (nonaxial)  Ex) acromioclavicular joint  Hinge Joints  Angular motion in a single plane (monaxial)  Ex) elbow  Pivot Joints  Rotation only (monaxial)  Ex) atlas and axis

28. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements

29. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  Ellipsoid Joints  Oval articular face within a depression  Motion in two planes (biaxial)  Ex) radiocarpal joint  Saddle Joints  Permits angular and circumduction motion, not rotation (biaxial)  Fit together like a rider in a saddle  Ex) first carpometacarpal joint  Ball-and-Socket Joints  Round articular face in a depression (triaxial) – all angular and rotational movements possible  Ex) shoulder and hip

30. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements Figure 9–6 Movements at Synovial Joints.

31. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Movements  A joint cannot be both mobile and strong  The greater the mobility, the weaker the joint  Mobile joints are supported by muscles and ligaments, not bone-to-bone connections

32. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intervertebral Articulations  The articulations between the superior and inferior articular processes of adjacent vertebrae are gliding joints that permit small movements associated with flexion and rotation of the vertebral column. Little gliding occurs between adjacent vertebral bodies.

33. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intervertebral Articulations  Intervertebral Articulations  C 2 to L 5 spinal vertebrae articulate  Intervertebral discs: –pads of fibrous cartilage –separate vertebral bodies –anulus fibrosus: »tough outer layer of intervertebral disc that surrounds nucleus pulposus »attaches disc to vertebrae –nucleus pulposus: »elastic, gelatinous core »absorbs shocks  As vertebral column moves  Nucleus pulposus shifts  Disc shape conforms to motion

34. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intervertebral Articulations Figure 9–7 Intervertebral Articulations.

35. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intervertebral Articulations  Intervertebral Ligaments  Bind vertebrae together  Stabilize the vertebral column  Ligaments interconnecting adjacent vertebrae include the following:  a. anterior longitudinal ligament – connects the anterior surfaces of adjacent vertebral bodies  b. posterior longitudinal ligament – parallels the anterior longitudinal ligament and connects the posterior surfaces of adjacent vertebral bodies  c. ligamentum flavum – connects the laminae of adjacent vertebrae  d. interspinous ligament – connects the spinous processes of adjacent vertebrae  e. supraspinous ligament – interconnects the tips of the spinous processes from C7 to the sacrum  f. ligamentum nuchae – extends from C7 to the base of the skull.

36. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Intervertebral Articulations  Damage to Intervertebral Discs  Slipped disc  Bulge in anulus fibrosus  Invades vertebral canal  Herniated disc  Nucleus pulposus breaks through anulus fibrosus  Presses on spinal cord or nerves

37. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Shoulder Joint  Permits the greatest range of motion of any joint  Most frequently dislocated joint  Joint is a ball-and-socket diarthrosis formed by the articulation of the head of the humerus with the glenoid cavity of the scapula

38. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Elbow Joint  A complex hinge joint that involves the humerus, radius, and ulna  The largest and strongest articulation at the elbow is the humeroulnar joint  Permits only flexion and extension  The elbow joint is extremely stable because:  the bony surfaces of the humerus and ulna interlock  a single, thick articular capsule surrounds both the humeroulnar and proximal radioulnar joints  the articular capsule is reinforced by strong ligaments

39. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Hip Joint  Also called coxal joint  Strong ball-and-socket diarthrosis  Wide range of motion

40. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint  A complicated hinge joint  Transfers weight from femur to tibia  Articulations of the knee joint  Two femur–tibia articulations  At medial and lateral condyles  One between patella and patellar surface of femur

41. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint  Menisci of the Knee  Medial and lateral menisci  Fibrous cartilage pads  At femur–tibia articulations  Cushion and stabilize joint  Give lateral support  Locking knees  Standing with legs straight: –“locks” knees by jamming lateral meniscus between tibia and femur

42. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint The menisci have three functions:  act as cushions  conform to the shape of the articulating surfaces as the femur changes position  provide lateral stability to the joint

43. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint  Seven Ligaments of the Knee Joint  Patellar ligament (anterior)  Two popliteal ligaments (posterior)  Anterior and posterior cruciate ligaments (inside joint capsule)  Tibial collateral ligament (medial)  Fibular collateral ligament (lateral)

44. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint Figure 9–12a The Knee Joint.

45. Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Knee Joint Figure 9–12b The Knee Joint.