Let's explore the human skeletal system and types of bones. The human body is the entire structure of a human organism and consists of a head, neck, torso, two arms, and two legs.

 

What is movement? Movement refers to the motion of all or a few parts of the body. Animals walk, run, fly, jump, crawl, slither and swim by moving one or more body parts. Let us look at some of our body movements. On performing various body movements, we conclude that we are able to move a few parts of our body easily in various directions and some only in one direction.

 

We are able to bend or rotate our body in places where two parts of the body seem to be joined together. �These places are called joints. Do you feel something hard while pressing body parts against your fingers? The hard structures are the bones.

 

We can bend or move our body only at those points where bones meet. There are different types of joints in our body to help us carry out different movements and activities. Similarly, there are many bones in the human skeletal system.

 

Now that you know that we are able to move the various parts of our body due to the presence of bones and joints. Let us now learn about the various different types of bones human skeletal system.

 

The Rib Cage

 

The Rib Cage is a bony and cartilaginous structure surrounding the chest cavity. It forms a major portion of the human skeleton system and provides attachment for the muscles of the neck, chest, upper abdomen, and back.

 

We see that the ribs are curiously bent. They join the backbone and the chest bone together to form a box-like structure; This is called the rib cage.

 

Let us understand the importance of rib cage.

 

1. It protects some of the vital internal organs of our body.
2. It provides protection to the lungs and the heart.
3. In addition to these, the abdomen and liver also lie protected inside this cage. It also anchors important muscles that work during breathing.

 

Arm Bones and Leg Bones

 

Have you ever imagined that what would happen if you don�t have any bone in your arm? It won�t be possible for you to hold or catch anything. Before we start defining the Arm and Leg bone, let�s do a simple activity. Press your leg and arm throughout, with the help of your fingers.

 

Feel the bones in your forearm, upper arm, lower leg, and upper leg. Try to find the number of bones if possible in each part. Similarly, feel the bones of your ankle and knee joints. Bend your fingers. Are you able to bend them at every joint? Can you count how many bones does your middle finger has? Feel the bones on the back of your palm. You will find many bones. Your wrist is also made up of several small bones.

 

Bones of the arm are :
� The Humerus
� The Ulna
� The Radius
� The Carpals
� The Metacarpals and
� The Phalanges

 

There are several small bones in the palm, wrist, and fingers. Arm bones are the power force of the skeleton. They enable the body to perform many important functions. The leg bones are similar to the arm bones except that they are bigger.

 

The leg bones are:
� The Femur
� The Tibia
� The Fibula
� The Carpals
� The Metacarpals and
� The Phalanges.

 

Leg bone enables the body to walk, run and support the body weight.

 

Shoulder Bone

 

The Shoulder is a very useful part of the body. The Shoulder has the Ball and Socket Joint that helps the arm to swing. The ball and socket joint allows the arm to rotate and swing. The human shoulder is made up of two important bones i.e. the Scapula and the Clavicle. The shoulder joint comprises the part of the body where the humerus or the bone of the upper arm attaches to the Scapula.

 

Backbone

 

Of the various different bones in our body, we have already learned about the Rib Cage. Let us now learn about another important part of the human skeleton - the backbone. Well, have you ever felt a long and hard structure starting from the neck running down at your back upto the buttocks or Pelvic bone? The backbone forms the main stem of the skeleton.

 

The backbone connects more or less to all the bones. Another important fact about the backbone is that it is not a single bone. Rather, it is made up of many small bones called vertebrae that work together to carry out practically each and every action.

 

Can you tell how we are able to bend our bodies? Well�bending is possible only because of the presence of multiple bones in the backbone. The rib cage is joined to these bones of the backbone. The backbone provides support for our body and helps to keep our body straight. It also protects our spine.

 

Pelvic Bones

 

The pelvic bones enclose the portion of our body below the stomach. Do you know which bones help us in sitting? Well, the answer is Pelvic bones. They take all the pressure of the body when we sit down. The pelvic bones also protect the organs of the lower abdomen like the urinary bladder, rectum, and also uterus in women.

 

Importance of Human Skeletal System

 

Have you ever thought about what gives the different parts of the body their different shapes? Actually, it is the skeleton which is a framework made of bones, cartilage, and ligaments that give shape to our body? The skeleton supports organs, anchors muscles, and protects organs.
The human skeleton system consists of the skull, hand bones, shoulder bones, rib cage, pelvic bones, backbone, leg bones, arm bones, and cartilages.

 

� The skull protects the brain.
� The shoulder has the ball and socket joint that helps the arm swing.
� The rib cage protects the lungs, heart, stomach, abdomen, and liver.
� The backbone runs from the neck down to the buttocks.
� The pelvic bone protects the lower abdominal organ such as the urinary bladder, rectum, and uterus.
� Cartilage is a soft bone tissue that connects joints. It is present in external parts like the ear and nose. Now, how do we know that this is the shape of a human skeletal system?

 

We can have some idea about the shape and number of bones in some parts of our body by feeling them. One way we could know this shape better would be to look at x-ray images of the human body. The x-ray shows the shapes of the bones in our bodies.

 

Now that you have studied the different bones in the human skeleton system, can you tell what bones are present in the ears? There are no bones in the ears. Instead, it is the cartilage.

 

Cartilage and Muscles

 

Cartilage is an additional part of the skeleton which is not as hard as a bone and can also be bent.
Let us find out exactly where this cartilage is present. Well, cartilage is present in external parts such as the ears and the nose. In addition, it is also present in the joints of our body. In the joints, it acts as a cushion or sponge and helps in a smooth movement.

 

The cartilage connects a bone to a muscle for movement. You must be wondering now what a muscle is? Let us learn about the muscle then. Have you ever observed a swollen region on your arm when you bend it to touch your shoulder? Well, it is the muscle and the swollen region is formed due to muscle contraction.

 

Similarly, the contraction of muscles can also be observed in our legs when we walk or run. But do you know why muscle is important? It covers and protects a bone and also helps it move. But how? Let us understand how it helps in the movement of the bone. During any action like walking or running or bending the arm, the muscle contracts and pulls the bone.

 

When contracted the muscle becomes become shorter, stiffer, and thicker. It is also important to note that muscles work in pairs. When one muscle pulls a bone, the other relaxes. To pull in the opposite direction, the relaxed muscle then contracts. While the one that pulled earlier relaxes and the bone moves back to its original position. In this way, the muscles take turns to help the bones move.

 

Read More- Joints: Types of Joints | Classification of Joints - Science Class 6