Question

What is joint? Describe the various types of joints with suitable examples.

Answer 1

Joint refers to articular surfaces where two bones meet. It is defined as a point or location between two bones where they meet. Joint provides a way of locomotion in animals. The type and character of the joint determine its movement and degree. The movability in joints vary.

Complete answer: Cartilage- It is smooth rubber-like or elastic tissue that covers the joints.
Ligaments- Bones are attracted to each other by tissues called ligaments.
Tendons- Muscles are attached to bones by tendons.
The classification of joints is based on structure and function :
Structural classification of joints:
1. Fibrous joints- These joints are also known as immovable joints. In these joints bones are not flexible. In these joints bones are fused to form a special structure. The most important example including the skull which is made up of fused bones has fibrous joints in the form of sutures, rib cage, the pelvic bone are the other examples. Three types of fibrous joints include- Gomphosis, sutures, and syndesmosis.
2. Cartilaginous joints- These joints are slightly immovable. These include symphysis or synchondrosis joints. These are found where the connection between articulating surfaces is made as a bone with cartilage.
a. Synchondrosis- Temporary cartilaginous joints found in children as epiphyseal played in long bones which help in growth in children.
b. Symphysis- Permanent cartilaginous joints found in adults including pubic symphysis.
3. Synovial joints- These joints are known as movable joints. These joints help in running, walking, typing, etc. These joints are the most common joint as they are responsible for a wide variety of movements in the body. These are very flexible joints.
Functional classification of joints: It is based on the type and degree of the movement they permit. It is a classification of synovial joints or freely movable joints. It includes six types of joints based on degree, movement, and location of joints.
i. Ball and socket joint- In his joint one bone is present in the hollow space of another bone. It helps in the rotatory movement. Example- Joints of shoulders.
ii. Pivotal joints- in this type of joint one bone is present in such a wag that full rotation is not possible and sees it helps in sideways and back forth movement. Example- Neck joint.
iii. Hinge joint- In these joints only back and forth movement is seen. Example- ankle, knee, and elbows.
iv. Gliding joints- It is also known as a planar joint and a common type of synovial joint. This joint allows two or more bones may be round or flat to move together freely. Examples include the lower leg to the ankle joint and the forearm to the wrist joint.
v. Saddle joint- It is a biaxial joint. It allows movement on two planes- flexion/extension and abduction/adduction. An example thumb is only a saddle joint.
vi. Condyloid joints- It is a joint which allows movement up-down and side to side. These joints are present at the base of index fingers, carpals of the wrist, etc.
Note: The primary function of joints is locomotion i.e. movement. Also, these joints apart from movement help in rotating and weight-bearing of the body. These joints are all free for movements in the body.