1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 07 Joints Part A

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Joints (Articulations)  Although joints are the weakest parts of the skeleton they allows our body to do a great variety of motions  Articulation – site where two or more bones meet  Functions of joints  1.- Give the skeleton mobility  2.- Hold the skeleton together Joints are classified by the structure and by their functions

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Joints: Structural  Structural classification focuses on the material binding bones together and whether or not a joint cavity is present  The three structural classifications are:  Fibrous (immovible)  Cartilaginous  Synovial (freely movable)

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Joints Classes Structural class CharacteristicsTypesMobility FibrousBone ends/parts united by collagenic fibers -Suture -Syndesmosis -Gomphorosis Immobile Slightly mobile Immobile CartilaginousBone ends/parts united by collagenic fibers -Synchondrosis -Symphysis Immobile Slightly mobile SynovialBone ends/parts covered with articular cartilage and enclosed within an articul. capsule lined with synovial memb. -Plane -Hinge -Pivot -Saddle -Condyloid -Ball and socket Freely movable (diartrosis)

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Joints: Functional  Functional classification is based on the amount of movement allowed by the joint  The three functional classes of joints are:  Synarthroses – immovable ( syn= together)  Amphiarthroses – slightly movable (amphi= on both sides)  Diarthroses – freely movable (through, apart). Predominates in limbs

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints  The bones are joined by fibrous tissues  There is no joint cavity  Most are immovable. The amount of movement allowed depends on the length of the connective tissue fibers uniting the bones  There are three types – sutures, syndesmoses, and gomphoses

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints: Sutures  Occur only between the bones of the skull  Comprised of interlocking junctions completely filled with connective tissue fibers  Bind bones tightly together, but allow for growth during youth  In middle age, skull bones fuse and are called synostoses  Because movement of the cranial bones would damage the brain, the immovable nature of sutures is a protective adaptation

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints: Sutures Figure 8.1a

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints: Syndesmoses  Bones are connected by a fibrous tissue ligament  Movement varies from immovable to slightly variable  Examples include the connection between the tibia and fibula, and the radius and ulna

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints: Syndesmoses Figure 8.1b

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Structural Joints: Gomphoses  The term gomphosis comes from the Greek gompho meaning “nail” or bolt”  Is a peg-in-socket fibrous joint. The only example is the articulation of a tooth and its alveolar socket  The fibrous connection is the periodontal ligament

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilaginous Joints  Articulating bones are united by cartilage  Lack a joint cavity  Two types – synchondroses and symphyses

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilaginous Joints: Synchondroses  A bar or plate of hyaline cartilage unites the bones  All synchondroses are synarthrotic  Examples include:  Epiphyseal plates of children  Joint between the costal cartilage of the first rib and the sternum

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilaginous Joints: Synchondroses Figure 8.2a, b

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilaginous Joints: Symphyses  Symphases: “growing together”  Hyaline cartilage covers the articulating surface of the bone and is fused to an intervening pad of fibrocartilage  Amphiarthrotic joints designed for strength and flexibility  Examples include intervertebral joints and the pubic symphysis of the pelvis

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cartilaginous Joints: Symphyses Figure 8.2c

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints  Those joints in which the articulating bones are separated by a fluid-containing joint cavity  All are freely movable diarthroses  Examples – all limb joints, and most joints of the body

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: General Structure  Synovial joints all have the following  1.- Articular cartilage  2.- Joint (synovial) cavity  3.- Articular capsule  4.- Synovial fluid  5.- Reinforcing ligaments

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: General Structure Figure 8.3a, b

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Friction-Reducing Structures  Bursae and tendon sheaths are not strictly part of synovial joints, but they are closely associated with them  Bursae – flattened, fibrous sacs lined with synovial membranes and containing synovial fluid  Common where ligaments, muscles, skin, tendons, or bones rub together  Tendon sheath – elongated bursa that wraps completely around a tendon

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Friction-Reducing Structures Figure 8.4

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Stability  Stability is determined by:  Articular surfaces – shape determines what movements are possible  Ligaments – unite bones and prevent excessive or undesirable motion  Muscle tone is accomplished by:  Muscle tendons across joints acting as stabilizing factors  Tendons that are kept tight at all times by muscle tone

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Movement  Every skeletal muscle of the body is attached to bone or other connective tissue structures at no fewer than two points.  The two muscle attachments across a joint are:  Origin – attachment to the immovable bone  Insertion – attachment to the movable bone  Described as movement along transverse, frontal, or sagittal planes

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints: Range of Motion  Range of motion allowed by synovial joints varies from:  Nonaxial – slipping movements only  Uniaxial – movement in one plane  Biaxial – movement in two planes  Multiaxial – movement in or around all three planes

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Range of Motion  Range of motion varies greatly in different people. There are three types of movements:  Gliding  Angular  Rotation

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Gliding Movements ( Also known as translation)  Are the simplest joint movements  One flat bone surface glides or slips over another similar surface  Examples – intercarpal and intertarsal joints, and between the flat articular processes of the vertebrae

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movement ( Increase or decrease the angle between two bones)  Flexion — bending movement that decreases the angle of the joint. Ex Bending the head forward on the chest  Extension — reverse of flexion; joint angle is increased. Ex Bending the head backward beyond its straight position  Dorsiflexion and plantar flexion — up and down movement of the foot  Abduction — movement away from the midline  Adduction — movement toward the midline  Circumduction — movement describes a cone in space

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Gliding Movement Figure 8.5a

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movement Figure 8.5b

30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movement Figure 8.5c, d

31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movement Figure 8.5e, f

32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Rotation  The turning of a bone around its own long axis  Examples  Between first two vertebrae  Hip and shoulder joints Figure 8.5g

33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Certain movements do not fit into any of the above categories and occur at only a few joints. There are:  Supination and pronation (forearm)  Inversion and eversion (foot)  Protraction and retraction (mandible)  Elevation and depression (mandible, chewing)  Opposition (thumb)

34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 8.6a

35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 8.6b

36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 8.6c

37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 8.6d

38. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 8.6e