Describe the general trends in range of motion of particular articulations in relation to the strength of a particular joint. Which joint is the most moveable joint in the body (you may have to look to a later spot in the presentation to find the answer for this)? Would you classify this joint as being rather strong, or a weak (easily injured) joint? 

Answer:

CLASSIFICATION OFJOINTS ARE ON TWO BASIS -

* STRUCTURE- On the basis of structure, joints of the human body are divided into the following:

i) Fibrous joints- The bones of the fibrous joints are held tightly by fibrous connective tissue.

RANGE OF MOTION- No movements- very less movements

Fibrous joints are further divided into sutures, syndesmoses and gomphoses.

• Sutures are present only in the skull where the bones are connected by short fibres of connective tissue which makes these bones immovable.
• Syndesmoses are joints are connected by a band of connective tissue , which allows somewhat greater amount of motion than the suture. Example of syndesmoses is the joint of the tibia and fibula in the ankle.
• Gomphoses are present between teeth and the teeth sockets. here the connection is through a ligament called the periodontal ligament.

ii) CARTILAGINOUS JOINTS- Here the bones are joined by cartilage. there are two types of cartilaginous joints:

• Synchondroses- Where the bones are joined by hyaline cartilage . Example are the epiphyseal plates of growing bones im children.
• Symphyses- Here the hyaline cartilage covers the end of the bones , but the connection is through the fibrocartilage. These are seen between vertebrae and between the pubic bones.

RANGE OF MOTION- SLIGHT MOVEMENTS.

iii) SYNOVIAL JOINTS- These type of joints have a special space between the bones, called the synovial cavity, which is filled with synovial fluid. The ends of the bones are covered by articular cartilage, which is hyaline in nature. The entire joint is surrounded ny the articular capsule. Examples of synovial joints are knee, elbow and shoulder joint .

  RANGE OF MOTION- WIDE VARIETY OF MOVEMENTS INCLUDING GLIDING, ANGULAR , ROTATIONAL

AND SPECIAL MOVEMENTS.

THE POINT TO BE NOTED HERE IS , THE MORE THE MOVABLE IS THE JOINT, THE WEAKER IT IS , AS IT IS MORE VUNERABLE TO DISLOCATIONS AND INJURIES . ALSO THE INFLAMMATION OF THE SYNOVIAL FLUID IS RESPONSIBLE FOR ARTHRITIS.

TYPES- i) PLANAR JOINTS- These includes joints in which articulating bones have flat or slightly curved articulating surfaces. These joints allows the gliding motion , therefore the joint is somtimes referred as gliding joint. Examples- carpal bones in the hands and the tarsals in the foot.

ii)HINGE JOINTS- In these type of joint , a slightly roumded end of one bone slightly hollow end of other bone .Here one bone is stationary and one moves , like a hinge of the door .

Examples- Elbow joint . Knee joint is sometimes called as modified hinge joints.

  iii) PIVOT JOINTS- Here the rounded end of one bone fits into a ring formed in the other bone. This allows foer the rotational movements '

Examples- Joint of the first and the second vertebrae of the neck, the wrist joint .

  iv) CONDYLOID JOINTS- It consists of an oval shaped end of one bone fitting into other oval shaped hollow of the other bone. It is also called the ellipsoidal joints. These types pf joints allows joints allows angular movements along two axes .

Example- joints of the fingers and the wrist.

v) SADDLE JOINTS - each bone of these joints looks like a saddle , which have concave and covex portions that fits together. These joints also allows angular movements but with a greater range.

Examples- Thumb joint.

vi) BALL AND SOCKET JOINTS- Here end of one bone is like a ball and end of other bone is like a socket that fits into one other . These type of joints allows the greatest range of movements .

Examples- Shoulder and hip joint.

*FUNCTIONAL CLASSIFICATION- This is on the basis of movement ability of the joint ,there are following types

• Synarthrosis- these are immovable joints. For example the joints between the skull bones.
• Amphiarthrosis- these allows slight movements, For example between the vertebrae.
• Diarthrosis- these are freely movable joints . For example the shoulder , knee , hip joints .

SYNOVIAL FLUID- It is a viscous fluid found in the synovial cavity .it is secreted by the synovial membrane, inner membrane of the synovial joints. It is an ultrafilterate from plasma . Its consists of proteins derived from blood plasma and from the cells of the joint tissues. Hyalouronan secreted by the fobroblast like cells . Lubricin secreted by the chondrocytes of the articular cartilage. Interstitial fluid from the blood plasma.

FUNCTIONS- there are several functions of the synovial fluid -

• lubricant- it acts as a lubricant and reduces the friction between the articulatimg surfaces.
• shock absorption- It has rheopeptic properties , that is , it becomes more viscous under pressure.
• nutrient and waste transportation- It supplies oxygen the nutrients and removes waste materials and carbon dioxide.