Joints, or articulations, are the structures where two or more bones meet, allowing for movement and providing mechanical support. They are essential for a wide range of motions and functions in the human body. Here's a detailed description of joints: ### Types of Joints Based on Structure: 1. **Fibrous Joints**: - **Description**: Connected by dense connective tissue rich in collagen. - **Movement**: Generally immovable (synarthrotic). - **Examples**: Sutures in the skull, syndesmoses between long bones like the tibia and fibula. 2. **Cartilaginous Joints**: - **Description**: Bones connected entirely by cartilage (either hyaline or fibrocartilage). - **Movement**: Allow limited movement (amphiarthrotic). - **Examples**: Intervertebral discs, pubic symphysis. 3. **Synovial Joints**: - **Description**: Characterized by a fluid-filled synovial cavity that separates the articulating bones. - **Movement**: Freely movable (diarthrotic), with various degrees and types of movement depending on the specific joint type. - **Examples and Subtypes**: - **Hinge Joints**: Permit flexion and extension (e.g., elbow, knee). - **Ball-and-Socket Joints**: Allow rotational movement and a wide range of motion (e.g., shoulder, hip). - **Pivot Joints**: Enable rotational movement around a single axis (e.g., atlantoaxial joint in the neck). - **Gliding Joints**: Allow sliding or gliding movements (e.g., intercarpal joints in the wrist). - **Saddle Joints**: Permit movement along two planes (e.g., thumb joint). - **Condyloid Joints**: Allow movement but no rotation (e.g., wrist joint between the radius and carpal bones). ### Types of Joints Based on Function: 1. **Synarthroses**: - **Description**: Immovable joints providing strong, stable connections. - **Examples**: Skull sutures. 2. **Amphiarthroses**: - **Description**: Slightly movable joints. - **Examples**: Intervertebral discs, pubic symphysis. 3. **Diarthroses**: - **Description**: Freely movable joints, synonymous with synovial joints. - **Examples**: Most limb joints like the knee, hip, shoulder. ### Joint Anatomy: - **Cartilage**: Covers the ends of bones, providing a smooth surface for movement and cushioning. - **Synovial Membrane**: Lines the joint capsule and secretes synovial fluid for lubrication. - **Ligaments**: Strong bands of connective tissue that connect bones and stabilize the joint. - **Tendons**: Connect muscle to bone, aiding in joint movement. - **Bursae**: Fluid-filled sacs that reduce friction between moving structures within the joint. ### Functions of Joints: - **Movement**: Facilitate a range of bodily movements, from gross motor functions like walking and lifting to fine motor skills like writing and typing. - **Support**: Maintain the body's structure and posture. - **Protection**: Protect internal structures by providing cushioning and absorbing impact.

1. JOINTS
When two or more bones meet at a point is called joints OR.. “Articulation”
Articulation means attachment.
Arthrology.
study of joint is called arthrology.
Arthritis.
Inflammation in the joint is called arthritis

2. Classification of joints
Classification of joints are mainly
three type…
Fibrous joints
Cartilaginous joints
Synovial joints

3. Fibrous joints
Fibrous joint lacks joint cavity.
Two bones are joined together by fibrous connective tissue.
Fibrous joints are joined together tightly so they are generally immobile in adults
although some allows slight movement.
For example
joint in skull and fix teeth into jaw

4. Fibrous joints can be further sub-classified into sutures, gomphoses and
syndesmoses
Sutures
Sutures are immovable joints (synarthrosis), and are only found between the
flat,-like bones of the skull
Gomphoses
Gomphoses are also immovable joints. They are found where the teeth articulate
with their sockets in the maxilla (upper teeth) or the mandible (lower teeth).
The tooth is bound into its socket by the strong periodontal ligament.
Syndesmoses
Syndesmoses are slightly movable joints (amphiarthroses).
They are comprised of bones held together by an interosseous membrane. The
middle radioulnar joint and middle tibiofibular joint are examples of a
syndesmosis joint.

6. Cartilaginous joints
In cartilaginous joints, bones are united together by a plate of hyaline cartilage.
Cartilaginous joints lack joint cavity
They are slightly movable or immobile
For example
Joints in vertebra

7. There are two main types:
Synchondroses
In a synchondrosis, the bones are connected by hyaline cartilage. These joints are
immovable (synarthrosis).
An example of a synchondrosis is the joint between the diaphysis and
epiphysis of a growing long bone.
Symphyses
Symphysial joints are where the bones are united by a layer of fibrocartilage.
They are slightly movable (amphiarthrosis).
Examples include the pubic symphysis, and the joints between vertebral bodies.

9. Synovial joints
Most of the permanent joints of body is synovial joint
All of the synovial joints allow greatest range of movement.
Movement is possible because, the end of bone at articulation is covered with
smooth hyaline cartilage and joint is lubricated by thick fluid called synovial fluid.
The joint is covered by flexible articular capsule

11. Synovial joints have further more types
Hinge joints
Ball & socket joint
Pivot joint
Sliding joint
Gliding joint
Condyloid joint
Saddle joint

12. Hinge joint
It allow movement in one plane
For example
Elbow, knee joint and Ankle joint

13. Ball & socket joint
Allow movement in many plans
For example
shoulder and hip joint.

14. Pivot joint
Allow twisting movement
For example
Cervical vertebra and radius etc.

15. Sliding joint
These joint in which the bones slides
over one another.
For example
Ankle and wrist joint.

16. Gliding joint
Joints bone move easily over one
another.
For example
joints in vertebra.

17. Condyloid joints
also known as ellipsoid joints,
They are oval -shaped bone known as a
condyle that fits into a similarly shaped cavity.
Although it similar to a ball and socket joint,
condyloid joints only allow for forward-
backward and side to side movement and do
not allow rotation.
Example
Wrist joint is the example of condyloid joint.

19. Saddle joint
Joint between trapezium of wrist and
1st metacarpal bone

21. Joints of upper limb
Most important and major joints of human body is;
Shoulder joint
Elbow joint
Wrist joint

22. Shoulder joint
It is synovial joint of ball and socket
verity
Head of humerus articulate with
gleniod cavity of scapula.
Its allow free movement of all direction
For example
Abduction, Adduction, Flexion ,
Extension and Circumduction

23. Elbow joint
Its is a hinge joint between the lower
end of humerus and ulna.
The movements allow it flexion and
extension.

24. Wrist joint
Its is condyloid joint between lower
end of radius and lower head of ulna
Movement occurs is flexion, extension ,
abduction , adduction.

25. Joints of lower limbs
Major joints of the lower limb is ;
Hip joints
Knee joint
Ankle joint

26. Hip joints
Synovial joint of ball and socket verity.
Head of femur articulate the
acetabulum.
Movement is flexion, extension,
abduction , adduction.

27. Knee joint
Its is a hinge joint.
Between the lower end of tibia and fibula.
Movement is flexion, extension, and slightly medial rotation.

28. Ankle joint
Its is a hinge joints
Between the lower end of tibia and fibula
Movement is flexion , extension , dorsiflexion, and planter flexion.