1. Articulations/Joints

2. Joint Classification A. Structural B. Functional
Two criteria:
1. +/- synovial cavity-space between bones often fluid-filled
2. Type of connective tissue binding bones
Fibrous-no synovial cavity-bones held by fibrous connective tissue
Cartilaginous-no synovial cavity-bones held by cartilage
Synovial-bones held by connective tissue of the articular capsule and
ligaments
B. Functional
Criteria:
1. Degree of movement
Synarthrosis-an immovable joint
Amphiarthrosis-a slightly movable joint
Diarthrosis-a freely movable joint-synovial

3. Fibrous Joints Sutures-example of an immovable joint (synarthrosis)
Syndesmoses-a fibrous joint that has greater distance between
articulating bones than a suture (e.g. the tibiofibular joint,
where the tibiofibular ligament conencts the tibia and
fibula).
Gomphoses-a fibrous joint where a cone-shaped peg fits into a socket-
(e.g. articulation between the teeth roots and alveoli of the
alveolar processes of the maxillae)

4. Fibrous Joints-Sutures

5. Cartilaginous Joints
Synchondroses-a joint in which the connecting material is hayline cartilage
(e.g. the epiphyseal plate connecting the epiphysis and
diaphysis of a growing bone)
Symphyses-a cartilaginous joint in which the ends of the articulating bone are
covered with hyaline cartilage. Occurs at the midline. (e.g. the
pubic symphysis connects the hip bones)

6.  Synovial Joints Structure of Synovial Joints
Unique in that they have a synovial cavity between articulating bones.
Classified as diarthroses
Bones are covered by a layer of hyaline cartilage called articular cartilage
Articular Capsule-a sleeve-like covering around a synovial joint consists
of two layers: an outer fibrous capsule and an inner synovial membrane.
The fibrous capsule (mostly collagen fibers)attaches to the periosteum of
the articulating bones. Some fibrous capsules are arranged in bundles
called ligaments.
The synovial membrane (areolar connective tissue with elastic fibers)
may include accumulation of fat pads called articular fat pads.
Synovial Fluid-Secreted by synovial membranes (hayluronic acid and
interstitial fluid). Lubricates joints, absorbes shocks, supplies nutrients
and removes wastes from chondrocytes within articular cartilage.
Accessory Ligaments- Extracapsular ligaments (outside the capsule).
Articular discs or menisci- stability, better joint fit, lubrication

7. Synovial Joints (cont’d)
Torn Cartilage-tearing of articular disks (menisci).
Sprain-forcible stretching of a joint that stretches or tears ligaments without dislocating bones.
Strain-stretched or partially torn muscle.
Bursae- Sac-like strutures that relieve friction in some joints (shoulder and knee). Not part of synovial joints but the capsules consist of connective tissue lined with synovial membrane. Tendon sheaths are tube-like bursae that wrap some tendons to lessen friction. Bursitis is an inflammation of bursae.

8. Types of joint movement at synovial joints
Gliding-bones move side-to-side, no significant
alteration in angle between bones

9. Types of joint movement at synovial joints-angular
Flexion-a decrease in the angle between articulating bones
Extension-and increase in the angle between articulating bones
Hyperextension-continuation of extension beyond the
anatomical position

10. Types of joint movement at synovial joints-angular
Flexion-a decrease in the angle between articulating bones
Extension-and increase in the angle between articulating bones
Hyperextension-continuation of extension beyond the
anatomical position

11. Types of joint movement at synovial joints-angular
Flexion-a decrease in the angle between articulating bones
Extension-and increase in the angle between articulating bones
Hyperextension-continuation of extension beyond the
anatomical position

12. Types of joint movement at synovial joints-angular
Lateral Flexion-decrease in the angle between articulating bones

13. Types of joint movement at synovial joints-angular
Abduction-movement away from the midline
Adduction-movement toward the midline
Circumduction-movement of the distal end of a
body part in a circle

14. Types of joint movement at synovial joints-angular
Abduction-movement away from the midline
Adduction-movement toward the midline

15. Types of joint movement at synovial joints-angular
Circumduction-movement of the distal end of a
body part in a circle

16. Types of Movements at Synovial Joints
Rotation-a bone revolving around its own longitudinal axis
e.g. turning the head from side-to-side at the
atlanto-axial joint (between the atlas and axis) when shaking
your head-”no”.
In limbs the rotation is defined relative to the midline
e.g. medial or internal rotation of the humerus
Special Movements-only occur at certain joints.
1. Elevation-upward movement opposes depression
2. Protraction-anterior movement opposes retraction
3. Inversion-inward movement of feet opposes eversion
4. Dorsiflexion-bending the foot at the ankle (standing on heels)
opposes plantar flexion
5. Supination-radioulnar movement where palm is face-up
opposes pronation (palm is face down)
6. Opposition- movement of thumb to touch fingers

17. Special Movements at Synovial Joints

18. Special Movements at Synovial Joints

19. Tendons and Ligaments
A tendon is a fibrous connective tissue which attaches muscle to bone. Tendons may also attach muscles to structures such as the eyeball. A tendon serves to move the bone or structure.
A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.

20. Tendons and Ligaments
The ligament or tendon is split into smaller entities called fascicles. The fascicle contains the basic fibril of the ligament or tendon, and the fibroblasts, which are the biological cells that produce the ligament or tendon. There is a structural characteristic at this level that plays a significant role in the mechanics of ligaments and tendons: the crimp of the fibril. The crimp is the waviness of the fibril.

21. Six Types of Synovial Joints-Planar
Articulating surfaces are flat or slightly curved-primarily
Involved in gliding movements

22. Six Types of Synovial Joints-Hinge
The convex surface of one bone fits into the
concave surface of another-monoaxial (movement in one axis)

23. Six Types of Synovial Joints-Pivot
The rounded or pointed surface of one bone articulates
with a ring formed by a bone and a ligament-monoaxial

24. Six Types of Synovial Joints-Condyloid
The oval-shaped convexity of one bone fits into
the oval-shaped depression in another bone-biaxial

25. Six Types of Synovial Joints-Saddle
An articular surface of one bone fits into the saddle-shaped
surface of another bone-biaxial

26. Six Types of Synovial Joints-Ball-and Socket
The ball-like surface of one bone fits into a cup-like depression
of another bone

27. Factors that affect range-of-motion
at synovial joints
Structure and shape of articulating bones
Strength and tension of joint ligaments
Arrangement and tension of muscles
Contact of soft body parts
Hormones- e.g. relaxin relaxes symphasis pubis
Disuse- e.g. lack of ROM after immobilization

28. Right Shoulder-Humeroscapular joint

29. Humeroscapular (Glenohumeral) Joint
Rotator cuff injury

30. Humeroscapular (Glenohumeral) Joint

31. Right Elbow Joint-medial view

32. Right Elbow Joint-lateral view

33. Right Hip Joint-anterior view

34. Right Hip Joint-posterior view

35. Right Hip Joint-frontal view

36. Right Knee Joint

37. Right Knee Joint

38. Joint disorders and aging
Aging-decreased synovial fluid, thinner articular cartilage,
ligaments shorten. Nearly everyone develops degeneration
in Knees, Elbows, Hips, and Shoulders.
Arthroplasty-repair of degenerated joints with artificial parts
e.g. full or partial hip replacement (head of the femur +/- the
acetabulum.
Disorders-
a. Rheumatism/arthritis-inflamation of bones, ligaments,
tendons, or muscles not caused by direct injury.
b. Osteoarthritis-degenerative disease resulting in
lost joint cartilage
c. Rheumatoid arthritis-autoimmune disease attacking
joint linings and cartilage
d. Gouty arthritis-uric acid build up resulting in crystals
deposited in joints-especially feet-can destroy joint-causing fusion
e. Lyme Disease-bacterial infection via tick bite affects large
joints (knee, ankle, elbow, hip, wrist)

39. End of Chapter 9