The Musculoskeletal System

Our bodies move because our body tells our brain what to do and then different parts of our bodies are used to make sure that this happens. Our bodies were designed with different features to help us move such as bones, muscles and joints.

Bones

There are over 206 bones in the human body such as the skull, vertebra, sternum, humerus, rib, radius, ulna, pelvis, ulna, femur, tibia and fibula, to name a few. The skull for example, helps to protect your brain and to make sure that your head and face stay the right shape.

Spine

The spine is made up of 26 different bones that run down the back and the neck. These bones are called the vertebrae and they have a job to make sure that your spinal cord is protected and to allow you to bend down. The vertebrae bones are stacked on top of each other in order to form the spine.

Ribs

Ribs are attached to your spine and they also help to protect your body. The rib cage helps to protect your organs that are located inside of your body. There are seven different pairs of ribs that are connected to the front of your chest to a bone that is called the sternum. There are also five pairs of ribs that are attached only to your spine.

Shoulder

Your shoulder bone to your elbow bones is called the humerus, and then this bone leads to two bones located in your wrist called the ulna and the radius and these bones allow you to rotate your arm.

Pelvis

The bone that is located at your hips is called the pelvis bone and it helps to support your spinal column and these bones help to protect the organs inside your body that are located at the lower part of your body.

The pelvis is connected to the femur which is the longest bone in your body and it goes from your hip to your knee and then this is connected to two smaller bones called the tibia and the fibula which helps you to rotate your feet.

Joints

The bones in our bodies have to be connected to something in order for us to be able to move. The bones are connected to joints. These joints connect two bones together and without these joints, our bodies would be stiff and would just fall apart.

Ligaments

The bones that have joints that are moveable are connected by ligaments which are tough bands of tissues that connect bones to other bones.

Hinge Joints

Joints that allow you to bend and straighten a part of your body are called hinge joints. Some of these include the knee and the elbow.

Pivot Joints

Pivot joints help you to be able to use your bones to turn. In order to turn your head left and right, you have pivot joints that are connected to the top of your spine. Some parts of your body have different combinations of joints.

The elbow for example has both pivot and hinge joints and this is what allows you to move your elbow left and right and side to side. Other parts of your body have ball and socket joints.

Ball and Socket Joint

The ball and socket joints allow your body to move in all directions. One example of this is your shoulder. Can you move your shoulder in a circle? This is because of the ball and socket joints.

Muscles

Muscles also help our bodies to move. Our body has over 600 different muscles and the muscles that are attached to the bones are called skeletal muscles. These muscles help us to move in a voluntary way or with voluntary movements. A movement is voluntary when we can control the movement.

Skeletal Muscles

Skeletal muscles are attached to the bones with tendons which are strong tissues that connect the muscles to the bone. Muscles are unable to push but they can pull and so sometimes they have to work in pairs in order to make a part of the body work.

Some important muscles in the body are the pectorals, biceps, abdominals, quadriceps, deltoid, triceps, gluteus maximus and the hamstring, to name a few.

Smooth Muscles

Muscles that do not have bones are located in different parts of your body. The stomach and intestines, for example, are smooth muscles. Smooth muscles contract and help you to move food throughout your body by pushing the food through the digestive system.

Cardiac Muscles

Cardiac muscles are muscles that contract to make your heart beat. Smooth and cardiac muscles are involuntary muscles which mean they move because your brain tells them to and you are not consciously in control of these movements. These movements happen when you aren’t even thinking about it.

Eye Muscles

Your eyes use muscles to look around. There are different muscles that are located on your eyeball that are not connected to any bones. These muscles are called skeletal muscles and they help to produce voluntary movements such as with your eyes.

There is a muscle that is attached to the bottom and top of your eyeball and the other end is attached to the eye socket in order to make the eyes move.

Face Muscles

There are also muscles that are located in your face that allows your body to make different expressions.

The orbicularis oris is part of your mouth that allows you to move your lips, the orbicularis occuli helps you to squint, the frontails helps you to raise your eyebrows and the zygomaticus major helps you to smile.

Facts About the Musculoskeletal System:

  • Babies are born with over 300 bones but when they reach adulthood, they only have 206 bones.
  • There are 27 bones in each hand.
  • The ball and socket joints are called that because one end of the bone fits into another bone that is cup shaped.
  • There are bones deep inside the body that look like sponges and these are called spongy bones.
  • The white layer of the bone is smooth and hard, and it is called the compact bone.
  • There is a jelly like material that is found inside the bone that makes red blood cells. This material is called bone marrow.
  • The bone has blood vessels and nerves on the outside.
  • Bones can repair themselves if they get broken.

What Did You Learn?

  • Muscles can only move one direction, what is that direction? Muscles can only pull and not push, and this is why the muscles oftentimes work together for movement.
  • What is the point of most bones? Most bones are used to protect organs or to help with movement.
  • What kind of muscle is located in the stomach and helps with digestion? Smooth muscles are found inside the stomach and help with digestion.
  • What kind of muscles help to contract the heart and causes the heart to beat? Cardiac muscles help the heart to beat.
  • What kind of joint helps your bones to turn? The pivot joints help your bones to turn.
  • What is connected to bones that have movable joints? Ligaments are connected to bones that have movable joints.

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