1. Biology 322 Human Anatomy I
Joints

2. Previously: Defined bones as organs of skeletal system
Also organs: joints (one or more types of tissues, all serving a common function)

3. Joints: Classified two ways:
1. What type of tissue connects the bones at the joint
2. How much motion the joint allows
Ordinary connective tissue = Fibrous joint
Hyaline or fibrous cartilage = Cartilagenous joint
Fluid-filled capsule (synovium) = Synovial joint
No motion = Synarthrosis
Limited motion = Amphiarthrosis
Freely movable = Diarthrosis

5. Fibrous Joints:
Bones connected by dense regular or dense irregular
connective tissue with many collagen fibers.
No joint cavity.
Depending on length of collagen fibers, may be synarthrotic (no motion) or
amphiarthrotic (limited motion)

6. Fibrous Joints:
Three subtypes:
1. Suture:
Collagen fibers very short
Always synarthrotic
Only in skull

7. Collagen fibers longer Amphiarthrotic (some motion)
Fibrous Joints:
Three subtypes:
(1. Suture: Collagen fibers very short, synarthrotic, only in skull)
2. Syndesmosis
Collagen fibers longer
Amphiarthrotic (some
motion)

8. Collagen fibers very short Synarthrotic (no motion)
Fibrous Joints:
Three subtypes:
(1. Suture: Collagen fibers very short, synarthrotic, only in skull)
(2. Syndesmosis: Collagen fibers longer, amphiarthrotic)
3. Gomphosis:
Collagen fibers very short
Synarthrotic (no motion)
Teeth in mandible or maxilla

9. Cartilagenous Joints:
Bones connected by some form of cartilage
No joint cavity.
Depending on length of collagen fibers, may be synarthrotic (no motion) or
amphiarthrotic (limited motion)

10. Cartilagenous Joints:
Two subtypes:
1. Synchondrosis:
Bones connected by hyaline cartilage
Synarthrotic or amphiarthrotic
Costosternal; Epiphyseal plates

11. Cartilagenous Joints:
Two subtypes:
(1. Synchondrosis: Bones connected by hyaline cartilage
Synarthrotic or amphiarthrotic; Costosternal; Epiphyseal plates)
2. Symphysis:
Bones connected by fibrous cartilage
Amphiarthrotic or synarthotic
Intervertebral disks;
Pubic symphysis

12. Synovial Joints:
Bones separated by synovial joint cavity, connected by
ligaments of dense regular connective tissue
Most synovial joints are diarthrotic
Some synovial joints are amphiarthrotic

13. Synovial Joints:
Components:
Proximal bone with
articular cartilage
Distal bone with
articular cartilage
Articular capsule with:
Fibrous capsule
Synovial membrane surrounding Synovial cavity
Ligaments of dense irregular connective tissue
Intrinsic = thickenings of fibrous capsule
Extracapsular = outside fibrous capsule
Intracapsular = inside synovial cavity

14. Proximal bone with articular cartilage
Synovial Joints:
Proximal bone with articular cartilage
Distal bone with articular cartilage
Articular capsule with Fibrous capsule,
Synovial membrane surrounding Synovial cavity
Intrinsic ligament = thickenings of fibrous capsule
Extracapsular ligament = outside of fibrous capsule
Intracapsular ligament = inside synovial cavity
In knee, sternoclavicular,
acromioclavicular, distal radioulnar,
and temporomandibular joints:
Also articular disk or meniscus of
fibrous cartilage

15. Synovial Joints:
Six types based on structure and type of motion:

16. Synovial Joints: Six types
1. Plane or Gliding
Gliding motion along flat articular surfaces.
Amphiarthrotic

17. Synovial Joints: Six types
2. Hinge joint
Motion around single axis
which is perpendicular
to long axis of the bones.
Often convex articular
surface on one bone
and
concave articular
surface on other bone.
Diarthrotic

18. Synovial Joints: Six types
3. Pivot joint
Motion around single axis
which is parallel
to long axis of the bones.
Often convex articular
surface on one bone
and
concave articular
surface on other bone.
Diarthrotic

19. Synovial Joints: Six types
4. Condyloid joint
Motion around two axes.
Articular surfaces of
both bones round or oval.
One shallowly convex
One shallowly concave
Diarthrotic

20. Synovial Joints: Six types
5. Saddle joint
Motion around two axes.
Articular surfaces of
both bones are:
Convex one direction
Concave other direction
Diarthrotic

21. Synovial Joints: Six types
6. Ball & Socket joint
Motion around all three axes.
Articular surfaces of one
bone forms "ball"
which fits into
"socket" on other bone.
Diarthrotic

22. We’ve noted that Synovial joints are stabilized by
Shapes of the articular surfaces of bones
Ligaments
Menisci
They are also stabilized by muscles and tendons which cross over the joint

23. Synovial joints often cushioned by a fluid-filled sac called a bursa which separates the joint from overlying muscles, tendons, or ligaments.

24. The following six specific synovial joints are described
in your textbook:
Jaw (Temporomandibular)
Shoulder (Glenohumoral or Humeroscapular)
Elbow (Humeroulnar, Humeroradial, and Radioulnar)
Hip (Femorocoxal or Coxal)
Knee (Tibiofemoral)
Ankle (Talotibial, Talofibular)
On exams, you should be able to briefly but accurately describe the structure of each of these joints, including all major ligaments; and you should be able to describe the actions for each

25. Movements of synovial diarthrotic joints:
Flexion and Extension

26. Movements of synovial diarthrotic joints:
Abduction and Adduction

27. Movements of synovial diarthrotic joints:
Rotation and Circumduction

28. Movements of synovial diarthrotic joints:
Protraction and Retraction

29. Movements of synovial diarthrotic joints:
Elevation and Depression

30. Movements of synovial diarthrotic joints:
Pronation and Supination

31. Movements of synovial diarthrotic joints:
Opposition (and Reposition)

32. Movements of synovial diarthrotic joints:
Movement of the foot at ankle joint
Inversion, Eversion
In the foot:
Pronation is used for:
dorsiflexion
+ abduction
+ eversion
Supination is used for:
plantar flexion
+ adduction
+ inversion
Dorsiflexion, Plantar flexion