Question

Bones are hard structures and cannot be bent. But, we can still bend our elbow, knee, etc. How is this possible?

Answer 1

Joints:

1. The place where the two bones meet is known as the joint.
2. A joint is a connection that occurs between bones in the skeletal system.
3. It is also known as an articulation or articular surface.
4. The type and characteristics of a given joint determine its degree and type of movement.
5. They can be classified on the basis of structure and function.
6. Some examples of joints are:

A) Ball and Socket Joints-

1. One end of the bone which is rounded and bone-like, fits into a cup-like depression of another bone.
2. This type of joint helps in rotatory movement.
3. An example ball and socket joint are the shoulders.

B) Pivotal Joints-

1. In this type of joint, one bone is rotated over a pivot -like end of another bone.
2. An example of a skull is rotated on the upper end of the axis vertebra.

C) Hinge Joints

1. Hinge joints are like door hinges, where only back and forth movement is possible.
2. Example of hinge joints is the ankle, elbows, and knee joints.

D) Saddle Joints

1. Saddle joint is the biaxial joint that allows the movement on two planes–flexion/extension and abduction/adduction.
2. For example, the thumb is the only bone in the human body having a saddle joint.

E) Condyloid Joints

1. Condyloid joints are the joints with two axes which permit up-down and side-to-side motions.
2. The condyloid joints can be found at the base of the index finger, carpals of the wrist, elbow and the wrist joints.
3. This joint is also known as a condylar joint.

Gliding Joints

1. Gliding joints are a common type of synovial joint.
2. It is also known as a plane or planar joint.
3. It occurs between bones of the wrist.