Question

Why do legs and arms have tube-like bones?

Answer 1

Bone is a rigid organ that is made up of calcium, sodium, phosphorus, other minerals, and collagen. It enables mobility in human beings and acts as the skeleton of the human body. They produce red and white blood cells and protect the organ from damage.

Complete answer:
Bones of legs and arms are made up of calcium salts and collagen which gives strength to the bones. It provides lightness to the bones and ensures that the legs and arms can move easily. The bones of legs and arms are hollow and have a tube-like structure as the bones must be highly strong and moveable. The bones are hollow to make it easier for the blood vessels and nerves to pass freely with these bones. The arm consists of the humerus and the leg contains femur bone. The humerus is hemispherical and the femur is two-third of a sphere. The position of the femur is strengthening in the acetabulum with the help of the strong ligament that connects the head of the femur. A true joint is formed at the ulna and humerus which is known as a hinge joint. The tibia and femur made up the knee joint which is the largest joint in the human body. The fibula is the next bone to the tibia which is a weaker bone of the lower leg. It is connected via ligaments to the two ends of the tibia. The kneecap which is also known as the patella helps in aiding knee extension and protects the joint.
The skeleton of the outer portion of the arms and legs consists of elongated portions which are made up of linear series, chains, of small bones. The foot of humans contains metatarsal bones and the hand contains metacarpal bones. The metatarsal bones are longer than the metacarpal bone. The metatarsal bone forms the arches of the foot and gives strength which enables it to act as a lever. The two bones of the foot which are known as the phalanges are larger than the corresponding bones in the hand which are shafts.

Note: Among the 206 bones in the human body, there are 26 bones in the human foot and the human hand consists of 54 bones which include the wrist. The longest bone of the human body is the femur. The most commonly broken bones are the arms which account for almost half of the adult broken bones. The most commonly broken bone among children is the collarbone. Sunni joints in the human body don’t move such as the skull.