1. Copyright © 2010 Pearson Education, Inc. Joints (Articulations) Articulation—site where two or more bones meet Functions of joints: Give skeleton mobility Hold skeleton together Case: Hyaluronic acid injections for knee osteoarthritis Joseph, a 45 year old construction worker has osteoarthritis. His knees have been bothering him and his physician recommended injections of hyaluronic acid.

2. Copyright © 2010 Pearson Education, Inc. Functional Classification of Joints Based on amount of movement allowed by the joint Three functional classifications: Synarthroses—immovable Amphiarthroses—slightly movable Diarthroses—freely movable

3. Copyright © 2010 Pearson Education, Inc. Structural Classification of Joints Based on material binding bones together and whether or not a joint cavity is present Three structural classifications: Fibrous Cartilaginous Synovial

4. Copyright © 2010 Pearson Education, Inc. Fibrous Joints Bones joined by dense fibrous connective tissue No joint cavity Most are synarthrotic (immovable) Three types: Sutures Syndesmoses Gomphoses

5. Copyright © 2010 Pearson Education, Inc. Fibrous Joints: Sutures Rigid, interlocking joints containing short connective tissue fibers Allow for growth during youth In middle age, sutures ossify and are called synostoses

6. Copyright © 2010 Pearson Education, Inc. Crouzon's and Apert's Syndrome Crouzon and Apert syndromes are the most common of the craniosynostosis syndromes. Craniosynostosis refers to the early closing of one or more of the sutures of an infant's head. The skull is normally composed of bones which are separated by sutures. This diagram shows the different sutures which can be involved. As an infant's brain grows, open sutures allow the skull to expand and develop a relatively normal head shape. If one or more of the sutures has closed early, it causes the skull to expand in the direction of the open sutures. This can result in an abnormal head shape. In severe cases, this condition can also cause increased pressure on the growing brain.

7. Copyright © 2010 Pearson Education, Inc. Figure 8.1a Dense fibrous connective tissue Suture line (a) Suture Joint held together with very short, interconnecting fibers, and bone edges interlock. Found only in the skull.

8. Copyright © 2010 Pearson Education, Inc. Fibrous Joints: Syndesmoses Bones connected by ligaments (bands of fibrous tissue) Movement varies from immovable to slightly movable Examples: Synarthrotic distal tibiofibular joint Diarthrotic interosseous connection between radius and ulna

9. Copyright © 2010 Pearson Education, Inc. Figure 8.1b Fibula Tibia Ligament (b) Syndesmosis Joint held together by a ligament. Fibrous tissue can vary in length, but is longer than in sutures.

10. Copyright © 2010 Pearson Education, Inc. Fibrous Joints: Gomphoses Peg-in-socket joints of teeth in alveolar sockets Fibrous connection is the periodontal ligament

11. Copyright © 2010 Pearson Education, Inc. Figure 8.1c Root of tooth Socket of alveolar process Periodontal ligament (c) Gomphosis “Peg in socket” fibrous joint. Periodontal ligament holds tooth in socket.

12. Copyright © 2010 Pearson Education, Inc. Cartilaginous Joints Bones united by cartilage No joint cavity Two types: Synchondroses Symphyses

13. Copyright © 2010 Pearson Education, Inc. Cartilaginous Joints: Synchondroses A bar or plate of hyaline cartilage unites the bones All are synarthrotic

14. Copyright © 2010 Pearson Education, Inc. Figure 8.2a Epiphyseal plate (temporary hyaline cartilage joint) Sternum (manubrium) Joint between first rib and sternum (immovable) (a) Synchondroses Bones united by hyaline cartilage

15. Copyright © 2010 Pearson Education, Inc. Ischiopubic Joint

16. Copyright © 2010 Pearson Education, Inc. Asymmetric Closure of Ischiopubic Synchondrosis in Pediatric Patients: Correlation with Foot Dominance OBJECTIVE. The enlarged ischiopubic synchondrosis is a well-known anatomic struc- ture; however, little is known about its physiology. In early childhood, enlargement of this synchondrosis occurs bilaterally, whereas before complete ossification, it is frequently found unilaterally. In most children, the unilateral enlarged ischiopubic synchondrosis is observed in the left hemipelvis, a finding that was hitherto unexplained. During common athletic activi- ties, increased ground reaction forces are exerted on the weight-bearing nondominant limb, which in up to 87% of the general population is the left leg. The asymmetric exertion of these forces may explain the distinct closure sequence of this temporary joint. The purpose of this study was to correlate unilateral enlarged ischiopubic synchondrosis with foot dominance. MATERIALS AND METHODS. The study cohort comprised 32 children who had un- dergone unenhanced radiography, CT, or MRI for reasons other than bone disorders and who presented with enlarged ischiopubic synchondroses. In these children, the distribution of en- larged ischiopubic synchondrosis and foot dominance were evaluated either retrospectively (n = 11) or prospectively (n = 21). RESULTS. In this cohort, 78% of patients were right-footed and 22% were left-footed. Nine of the 32 children presented with unilateral enlarged ischiopubic synchondrosis (left, seven [78%] of nine; right, two [22%] of nine). All children with enlarged left ischiopubic synchondrosis were right- footed, and all children with enlarged right ischiopubic synchon- drosis were left-footed. CONCLUSION. Unilateral enlarged ischiopubic synchondrosis is closely correlated with foot dominance. The asymmetric ossification pattern of the ischiopubic synchondrosis indicates delayed ossification of this anatomic structure due to asymmetrically applied me- chanical forces to the nondominant limb.

17. Copyright © 2010 Pearson Education, Inc. Cartilaginous Joints: Symphyses Hyaline cartilage covers the articulating surfaces and is fused to an intervening pad of fibrocartilage Strong, flexible amphiarthroses

18. Copyright © 2010 Pearson Education, Inc. Figure 8.2b Fibrocartilaginous intervertebral disc Pubic symphysis Body of vertebra Hyaline cartilage (b) Symphyses Bones united by fibrocartilage

19. Copyright © 2010 Pearson Education, Inc. Diastasis symphysis pubis is the separation of normally joinedpubic bones, as in the dislocation of the bones, without a fracture.

20. Copyright © 2010 Pearson Education, Inc. Synovial Joints All are diarthrotic Include all limb joints; most joints of the body

21. Copyright © 2010 Pearson Education, Inc. Synovial Joints Distinguishing features: 1.Articular cartilage: hyaline cartilage 2.Joint (synovial) cavity: small potential space

22. Copyright © 2010 Pearson Education, Inc. Synovial Joints Distinguishing features: 3.Articular (joint) capsule: Outer fibrous capsule of dense irregular connective tissue Inner synovial membrane of loose connective tissue

23. Copyright © 2010 Pearson Education, Inc. Synovial Joints Distinguishing features: 4.Synovial fluid: Viscous slippery filtrate of plasma + hyaluronic acid Lubricates and nourishes articular cartilage Case: Hyaluronan is also used to treat osteoarthritis of the knee. Such treatments, called viscosupplementation, are administered as a course of injections into the knee joint, and are believed to supplement the viscosity of the joint fluid, thereby lubricating the joint, cushioning the joint, and producing an analgesic effect.

24. Copyright © 2010 Pearson Education, Inc. Osteoarthritis is caused by 'wear and tear' on a joint. Cartilage is the firm, rubbery tissue that cushions your bones at the joints, and allows bones to glide over one another. Cartilage can break down and wear away. As a result, the bones rub together, causing pain, swelling, and stiffness. Bony spurs or extra bone may form around the joint, and the ligaments and muscles become weaker and stiffer.

25. Copyright © 2010 Pearson Education, Inc. Figure 8.3 Periosteum Ligament Fibrous capsule Synovial membrane Joint cavity (contains synovial fluid) Articular (hyaline) cartilage Articular capsule

26. Copyright © 2010 Pearson Education, Inc. Synovial Joints Distinguishing features: 5.Three possible types of reinforcing ligaments: Capsular (intrinsic)—part of the fibrous capsule Extracapsular—outside the capsule Intracapsular—deep to capsule; covered by synovial membrane

27. Copyright © 2010 Pearson Education, Inc. Synovial Joints Distinguishing features: 6.Rich nerve and blood vessel supply: Nerve fibers detect pain, monitor joint position and stretch Capillary beds produce filtrate for synovial fluid

28. Copyright © 2010 Pearson Education, Inc. The cause of RA is unknown. It is an autoimmune disease, which means the body's immune system mistakenly attacks healthy tissue. RA can occur at any age, but is more common in middle age. Women get RA more often than men. Infection, genes, and hormone changes may be linked to the disease.

29. Copyright © 2010 Pearson Education, Inc.

30. Synovial Joints: Friction-Reducing Structures Bursae: Flattened, fibrous sacs lined with synovial membranes Contain synovial fluid Commonly act as “ball bearings” where ligaments, muscles, skin, tendons, or bones rub together

31. Copyright © 2010 Pearson Education, Inc. Figure 8.4b Coracoacromial ligament Subacromial bursa Cavity in bursa containing synovial fluid Bursa rolls and lessens friction. Humerus head rolls medially as arm abducts. (b) Enlargement of (a), showing how a bursa eliminates friction where a ligament (or other structure) would rub against a bone Humerus resting Humerus moving

32. Copyright © 2010 Pearson Education, Inc. Prepatellar bursitis, also known as Housemaid's knee, is a common cause of swelling and pain above the patella (kneecap), and is due to inflammation of the prepatellar bursa. This structure is a superficial bursa with a thin synovial lining located between the skin and the patella. The bursa develops within the first years of life as a result of mechanical pressure and friction, and it serves the purpose of reducing friction on underlying structures and allowing maximal range of motion in the knee. Aseptic prepatellar bursitis is commonly caused by repetitive work in a kneeling position, hence the name "housemaid's knee"...

33. Copyright © 2010 Pearson Education, Inc. Synovial Joints: Friction-Reducing Structures Tendon sheath: Elongated bursa that wraps completely around a tendon

34. Copyright © 2010 Pearson Education, Inc. Figure 8.4a Acromion of scapula Joint cavity containing synovial fluid Synovial membrane Fibrous capsule Humerus Hyaline cartilage Coracoacromial ligament Subacromial bursa Fibrous articular capsule Tendon sheath Tendon of long head of biceps brachii muscle (a) Frontal section through the right shoulder joint

35. Copyright © 2010 Pearson Education, Inc. Stabilizing Factors at Synovial Joints Shapes of articular surfaces (minor role) Ligament number and location (limited role) Muscle tone, which keeps tendons that cross the joint taut Extremely important in reinforcing shoulder and knee joints and arches of the foot

36. Copyright © 2010 Pearson Education, Inc. Synovial Joints: Movement Muscle attachments across a joint: Origin—attachment to the immovable bone Insertion—attachment to the movable bone Muscle contraction causes the insertion to move toward the origin Movements occur along transverse, frontal, or sagittal planes

37. Copyright © 2010 Pearson Education, Inc. Synovial Joints: Range of Motion Nonaxial—slipping movements only Uniaxial—movement in one plane Biaxial—movement in two planes Multiaxial—movement in or around all three planes

38. Copyright © 2010 Pearson Education, Inc. Summary of Characteristics of Body Joints Consult Table 8.2 for: Joint names Articulating bones Structural classification Functional classification Movements allowed

39. Copyright © 2010 Pearson Education, Inc. Table 8.2 (1 of 4)

40. Copyright © 2010 Pearson Education, Inc. Table 8.2 (2 of 4)

41. Copyright © 2010 Pearson Education, Inc. Table 8.2 (3 of 4)

42. Copyright © 2010 Pearson Education, Inc. Table 8.2 (4 of 4)

43. Copyright © 2010 Pearson Education, Inc. Movements at Synovial Joints 1.Gliding 2.Angular movements: Flexion, extension, hyperextension Abduction, adduction Circumduction 3.Rotation Medial and lateral rotation

44. Copyright © 2010 Pearson Education, Inc. Movements at Synovial Joints 4.Special movements Supination, pronation Dorsiflexion, plantar flexion of the foot Inversion, eversion Protraction, retraction Elevation, depression Opposition

45. Copyright © 2010 Pearson Education, Inc. Gliding Movements One flat bone surface glides or slips over another similar surface Examples: Intercarpal joints Intertarsal joints Between articular processes of vertebrae

46. Copyright © 2010 Pearson Education, Inc. Figure 8.5a Gliding (a) Gliding movements at the wrist

47. Copyright © 2010 Pearson Education, Inc. Angular Movements Movements that occur along the sagittal plane: Flexion—decreases the angle of the joint Extension— increases the angle of the joint Hyperextension—excessive extension beyond normal range of motion

48. Copyright © 2010 Pearson Education, Inc. Figure 8.5b (b) Angular movements: flexion, extension, and hyperextension of the neck HyperextensionExtension Flexion

49. Copyright © 2010 Pearson Education, Inc. Figure 8.5c Hyperextension Flexion Extension (c) Angular movements: flexion, extension, and hyperextension of the vertebral column

50. Copyright © 2010 Pearson Education, Inc. Figure 8.5d Extension Flexion (d) Angular movements: flexion and extension at the shoulder and knee

51. Copyright © 2010 Pearson Education, Inc. Angular Movements Movements that occur along the frontal plane: Abduction—movement away from the midline Adduction—movement toward the midline Circumduction—flexion + abduction + extension + adduction of a limb so as to describe a cone in space

52. Copyright © 2010 Pearson Education, Inc. Figure 8.5e Abduction Adduction (e) Angular movements: abduction, adduction, and circumduction of the upper limb at the shoulder Circumduction

53. Copyright © 2010 Pearson Education, Inc. Rotation The turning of a bone around its own long axis Examples: Between C 1 and C 2 vertebrae Rotation of humerus and femur

54. Copyright © 2010 Pearson Education, Inc. Figure 8.5f Lateral rotation Medial rotation Rotation (f) Rotation of the head, neck, and lower limb

55. Copyright © 2010 Pearson Education, Inc. Special Movements Movements of radius around ulna: Supination (turning hand backward) Pronation (turning hand forward)

56. Copyright © 2010 Pearson Education, Inc. Figure 8.6a Supination (radius and ulna are parallel) (a) Pronation (P) and supination (S) Pronation (radius rotates over ulna)

57. Copyright © 2010 Pearson Education, Inc. Special Movements Movements of the foot: Dorsiflexion (upward movement) Plantar flexion (downward movement)

58. Copyright © 2010 Pearson Education, Inc. Figure 8.6b Dorsiflexion Plantar flexion Dorsiflexion Plantar flexion (b) Dorsiflexion and plantar flexion

59. Copyright © 2010 Pearson Education, Inc. Special Movements Movements of the foot: Inversion (turn sole medially) Eversion (turn sole laterally)

60. Copyright © 2010 Pearson Education, Inc. Figure 8.6c Eversion Inversion (c) Inversion and eversion

61. Copyright © 2010 Pearson Education, Inc. Special Movements Movements in a transverse plane: Protraction (anterior movement) Retraction (posterior movement)

62. Copyright © 2010 Pearson Education, Inc. Figure 8.6d Protraction of mandible Retraction of mandible (d) Protraction and retraction

63. Copyright © 2010 Pearson Education, Inc. Special Movements Elevation (lifting a body part superiorly) Depression (moving a body part inferiorly)

64. Copyright © 2010 Pearson Education, Inc. Figure 8.6e Elevation of mandible Depression of mandible (e) Elevation and depression

65. Copyright © 2010 Pearson Education, Inc. Special Movements Opposition of the thumb Movement in the saddle joint so that the thumb touches the tips of the other fingers

66. Copyright © 2010 Pearson Education, Inc. Figure 8.6f (f) Opposition Opposition