Joints

1
Joints

• Chapter 7

2
Joints

• Places where bones meet
• Classified structurally by anatomy
• Classified structurally by motion

3
Structural Classification

• Based on material between bones
• Fibrous joints- no cavity just fiberous
  Connective tissue
• Cartilaginous joints- bones held together by
  cartilage
• Synovial joints- have synovial cavity and dense
  irregular tissue of articular capsule and often
  ligaments

4
Functional Joints

• Synarthrosis- immoveable
• pelvis , sutures,, teeth
• Amphiarthrosis- slight movement
• Epiphysis, tibia-fibula, vertebrae and pelvic
  symphysis
• Diarthroses- free movement synovial
• defined by movement

5
Fibrous Joints

• Little or no movement
• Suture- e.g. skull (synarthrosis)
• joined by thin layer of dense fibrous connective
  tissue
• Syndesmosis- e.g.tibia fibula amphiarthrosis
• Greater distance and amount of dense fibrous
  material
• Gomphosis- e.g. tooth root in socket
  synarthrosis

6
Figure 7.1a
7
Figure 7.1b
8
Figure 7.1c
9
Cartilaginous joint

• Synchondrosis- hyaline cartilage
• E.g epiphyseal plate synarthrosis
• Symphysis- fibrocartilage join
• E.g. pubic symphysis and intervertebral joints
  amphiarthrosis

10
Figure 7.2a
11
Figure 7.2b
12
Synovial Joints

• Synovial cavity
• Articular cartilage
• Articular capsule-
• Inner layer synovial secretory membrane
• Synovial fluid
• Ligaments
• Some contain menisci

13
Figure 7.3
14
Bursae

• Located where friction can occur
• E.g. between skin bone or bone tendons,
  ligaments or other bones
• Structurally similar to joint capsules- Contain
  synovial membrane and fluid.

15
Figure 7.10a
16
Figure 7.10b
17
Figure 7.10c
18
Figure 7.10d
19
Types of motions at synovial joints

• Gliding-
• flat bone surfaces moving across each other
• Flexion-
• decrease in angle between articulating bones
• Extension-
• Increase in angle between articulating bones
• Hyperextension
• Bending beyond 180o degrees e.g. moving humerus
  backwards behind anatomical position

20
Figure 7.4a
21
Figure 7.4b
22
Figure 7.4c
23
Figure 7.4d
24
Figure 7.4e
25
Figure 7.4f
26
Motion (cont.)

• Abduction-
• Movement of bone away from midline
• Adduction-
• Movement of bone toward midline
• Circumduction-
• Movement of distal end in a circle
• Rotation-
• Bone revolves around its own longitudinal axis

27
Figure 7.5a
28
Figure 7.5b
29
Figure 7.5c
30
Figure 7.6a
31
Figure 7.6b
32
Figure 7.7a
33
Figure 7.7b
34
Special Movements

• Elevation- lift upward
• Depression- downward movement
• Protraction movement forward
• Retraction- movement back to anatomical position

35
Figure 7.8ab
36
Figure 7.8cd
37
Special Movements (cont.)

• Inversion- move of soles medially
• Eversion- move soles laterally
• Dorsiflexion- bending of foot toward dorsum
• Plantar flexion- bend foot toward plantar surface

38
Figure 7.8ef
39
Figure 7.8g
40
Special Movements (cont.)

• Supination- movement of forearm so palms face
  forward or upward
• Pronation- movement of forearm so palms face
  backward or downward

41
Figure 7.8h
42
Types of Synovial Joints

• Planar joints- articulating surfaces flat or
  slightly curved
• Hinge joints- convex to concave surface
• Only do flexion and extension
• Pivot joints- rounded surface with ring formed by
  bone and ligament
• e.g. atlantoaxial joint

43
Types of Synovial Joints

• Condyloid joints- convex oval surface to concave
  oval surface
• e.g. wrist metacarpophyangeal joints
• Saddle joints- one side saddle shaped other sits
  astride it
• Ball socket joints- ball like surface into cup
  like socket surface
• Can do flexion/extension, adduction/adduction
  rotation

44
Figure 7.9a
45
Figure 7.9b
46
Figure 7.9c
47
Figure 7.9d
48
Figure 7.9e
49
Figure 7.9f
50
Aging of Joints

• Slowing of synovial fluid production
• Thinning of articular cartilage
• Ligaments shorten and lose flexibility
• Influenced by genetic factors