1. The Skeletal System: Articulations

2. Introduction
Joints, or articulations, are connections between bones that may or may not permit movement.
Cartilage, fluid, or dense connective tissues is usually involved in holding joints together.
Joints maybe classified structurally or functionally

3. Classification of Articulations - Structural
Structural Classification
1) Fibrous – No joint cavity – fibrous tissue
a) Suture – very thin fibrous tissue
if fused – synostoses
b) Syndesmosis – broader fibrous tissue
fontanel
c) Gomphosis – peg in cone
example: tooth in jaw
2) Cartilaginous – No joint cavity – Cartilage
a) Synchondrosis – hyaline cartilage
epiphyseal plate
b) Symphysis – fibrocartilage
symphysis pubis and intervertebral disks
3) Synovial – Joint (Synovial) cavity
a) Gliding – intertarsal
b) Hinge – knee and ankle
c) Pivot – atlantoaxial
d) Condyloid or Ellipsoidal – wrist
e) Saddle – thumb
f) Ball and Socket – should and hip

4. Classification of Articulations Functional
Functional Classification of Joint
1) Synarthroses – Immovable Joints
a) Suture
b) Gompohsis
c) Synchondrosis
2) Amphiarthrosis – Slightly movable joints
a) Symphysis – pubic symphysis
b) Syndesmosis - tibia and fibula
3) Diarthrosis – Freely movable
a) Gliding – gliding
b) Hinge – flex and extend (1 plane)
c) Pivot – rotation – 1 plane
d) Condyloid or Ellipsoidal – 2 planes
flex, extend, abduct and adduct
e) Saddle – – 2 planes
f) Ball and Socket – (3 planes)
flex, extend; abduct adduct; and medial and lateral rotation

5. Synarthroses (Immovable Joints)
Sutures are joints found only in the skull.
Bony edges interlock and short dense connective tissue fiber hold the bones together.
A gomphosis is the joint between a tooth and the alveolar fossa of the maxillae or mandible.
Periodontal ligaments (PDL) hold the tooth to the bone in the gomphosis.
A synchondrosis is a joint in which hyaline cartilage separates the ends of the bones involved in the joint.
A synostosis occurs if bones fuse together to form one bone.

6. Amphiarthroses (Slightly Movable Joints)
A syndesmosis occurs when to bones are connected by relatively long connective tissue ligaments.
Connecting bones using a fibrocartilage pad forms a symphysis. 

7. Diarthroses (Freely Movable Joints)
Synovial joints are typically found at the ends of long bones in the upper and lower limbs.
All synovial joints have six basic characteristics:
A joint capsule
Articular cartilages
A joint cavity filled with synovial fluid
A synovial membrane lining the joint capsule

8. Synovial Joints
Figure 8.1 Structure of a Synovial Joint

9. Synovial fluid has three functions:
Lubricates the surfaces of the articular cartilages on the ends of the bones.
Nourishes the chondrocytes by entering and exiting the articular cartilages due to the forces acting on the joint.
Acts as a shock absorber.

10. Types of Movements
Angular movements
Rotation
PLAY
Movements

11. Movements at the ankle include:
Special Movements
Movements at the ankle include:
Eversion/inversion
Dorsiflexion/plantar flexion
Movement of the vertebral column includes:
Lateral flexion
Movement of the pollex (thumb):
Opposition/reposition

12. Movements that occur at many joints include:
Special Movements
Movements that occur at many joints include:
Protraction: anterior movement in the horizontal plane
Retraction: posterior movement in the horizontal plane
Elevation: cranial movement in the vertical axis
Depression: caudal movement in the vertical axis

13. Structural Classification of Synovial Joints
Plane joints:  
Nonaxial or multiaxial
Hinge joints:
flexion and extension
Pivot joints:
rotational movements
PLAY
Joint Structure

14. Structural Classification of Synovial Joints
Condylar joints:
flexion/extension and abduction/adduction
Saddle joints:
biaxial joints that also allow circumduction
Ball and socket joints:
triaxial joints

15. The Temporomandibular Joint
Figure 8.7a,b The Temporomandibular Joint (TMJ)

16. Intervertebral Articulations
Figure 8.8a Anterior Vertebral Column
Figure 8.8b Lateral Vertebral Column

17. There are four possible movements of the vertebral column:
Vertebral Movements
There are four possible movements of the vertebral column:
Anterior flexion, or bending forward
Extension, or bending backward
Lateral flexion, or bending to the side
Rotation–twisting

18. The Sternoclavicular Joint
Figure The Sternoclavicular Joint

19. The Shoulder Joint Figure 8.11a The Anterior Shoulder
Figure 8.11b The Lateral Shoulder

20. The Shoulder Joint Figure 8.11c Sectional Shoulder
Figure 8.11d Superior Shoulder

21. The Elbow Joint Figure 8.12a Medial Elbow
Figure 8.12d Longitudinal Elbow

22. The Wrist
Figure 8.13b Wrist Joints
Figure 8.13c Wrist Ligaments

23. The Joints of the Hand
Figure 8.13d Joints of the Hand

24. The Hip Joint
Figure 8.14a Lateral Hip
Figure 8.14c Posterior Hip

25. The Hip Joint
Figure 8.14b Anterior Hip
Figure 8.15a Sectional Hip

26. The Knee
Figure 8.16a Anterior Knee
Figure 8.16b Parasagittal Knee

27. The Knee Figure 8.17a Posterior Superficial
Figure 8.17b Posterior Deep

28. The Knee
Figure 8.17c Anterior Knee

29. The Ankle and Foot Figure 8.18a Ankle and Foot
Figure 8.18b Ankle and Foot MRI