Joints are where two bones meet, allowing movement and connecting the skeleton. They can be classified by function, like synarthroses which don't move, or amphiarthroses which move partially. Most common are diarthroses, which move freely. Structurally, joints are fibrous, cartilaginous, or synovial. Synovial joints have a cavity filled with fluid and include knee, elbow, shoulder joints. They allow motions like flexion, extension, and rotation. Understanding joints is key to learning bone and muscle anatomy.

1. Joints
Group 3

2. JOINTS
– Defined: any place where two bones come
together
– General Function of Joints:
- Hold the skeleton together
- Allow for increased mobility and flexibility of
skeleton

3. CLASSIFICATION OF JOINTS
 Joints can be classified based on:
-function (what kind of movement they
allow)
-structure (what material is found in the
joint and if is there a joint cavity present).

4. Functional classification
 Synarthroses – joints that have NO
movement.
– Examples: sutures of the skull, gomphoses- teeth
 Amphiarthroses – partially movable joints.
– Examples: intervertebral disc and pubic symphysis
 Diarthroses – freely movable joints.
The most common type of functional joint in
the body.
– Examples: knee joint, shoulder joint, finger joints, ankle and
wrist joints, etc.

5. Structural Classification
1. Fibrous joints (synarthroses): adjacent
bones are joined by collagen fibers. 3 kinds:
- sutures, gomphoses and syndesmoses.
2. Cartilaginous joints (amphiarthroses):
two bones are joined by cartilage. 2 kinds:
- synchondroses, and symphyses.
3. Synovial joints (Diarthroses): freely
movable and most common joint in the
body.

6. Joint mobility comparison
Note that as mobility decreases, stability increases.

7. Fibrous joints (synarthroses):

8. Cartilaginous joints
(amphiarthroses)

9. Synovial Joints (diarthroses)
 this type of joint is defined by the
presence of a joint cavity filled with fluid.
 Most joints of the body fall into this class.
Examples: knee joint, elbow joint, shoulder and hip
joints and the phalanges of hands and feet, etc.

10. Structures in a Synovial Joint
1. articular capsule – external and internal
2. joint/synovial cavity – filled with synovial fluid
3. articular cartilage – Hyaline cartilage
4. synovial fluid – viscous/ clear colorless fluid
5. ligaments – give the joint reinforcement and
strength
6. Nerves – provide feelings of pain and stretch
7. Vessels - provide nutrients to joint

11. Typical Synovial Joint

12. Additional joint structures
 Ligaments- join bones to bones
– Consists of dense regular connective tissue.
 Tendons- join muscles to bone
– Consists of dense regular connective tissue.
 Bursae- fibrous sac lined with synovial
membrane and containing synovial fluid
– Occurs between bones and tendons or muscles
– Acts to decrease friction during movement

13. Types of Synovial Joints
1. Plane (gliding) Joints
2. Hinge Joints
3. Pivot Joints
4. Condyloid Joints
5. Saddle Joints
6. Ball and Socket Joints

15. Movements allowed by Synovial Joints
1. gliding – - bony surfaces of bone slide or glide over
each other
2. flexion –- bending movement that decreases the angle
3. extension – movement the increases the angle,
opposite of lexion
4. abduction –moving away from longitudinal axis
5. adduction –movement toward the longitudinal axis
6. circumduction –movement of the limb such that it
describes a cone
7. rotation – turning the bone or limb around its long axis
8. supination –rotating the forearm laterally such that the
palm faces superiorly

16. Movements allowed by Synovial Joints
9. pronation –- rotating the forearm medially such that
the palm faces inferiorly
10. inversion –- sole of the foot faces or turns medially
11. eversion –- sole of the foot turn laterally
12. protraction –-juttting out of the jaw
13. retraction –- moving the jaw backward
14. elevation –- lifting the limb or body superiorly
15. depression –- moving the body part inferiorly
16. opposition –- to bring the thumb and index finger
tips together

17. Body movements

18. Extension and flexion

19. Abduction and adduction

20. Protraction/Retraction Pronation/Supination
Opposition of thumb and pinky

21. Elevation/ Depression
Inversion/Eversion

22. Circumduction