The human body is the result of millions of years of evolution. Dexterity and bipedal locomotion have helped us reach where we are. Anatomically, humans have the following characteristics:
- A newborn infant has 305 bones at birth, and it eventually decreases to 206 bones by adulthood.
- Bones provide a definite shape to our body. Skeleton is the framework given to our body as a result of the fusion of bones. It is made up of bones, cartilage and joints. One way to know the shape of your bones is through X-ray images. Our hand is made up of small bones called carples.
- Ribs are bent to form the chest bone. The chest bone and backbone together join to form the rib cage. The rib cage consists of 12 ribs on each side of the chest. It protects our internal organs such as the heart, lungs etc.
- The rib cage is joined to the backbone. It consists of 33 small bones called vertebrae. Backbone helps our body stay erect and provides posture.
- Bones near the shoulder area are called shoulder bones and those present in the abdominal region are called pelvic bones, which encloses the portion of our body just below the stomach.
- Skull is joined together by many bones and encloses our brain.
- The additional part of the skeleton that can be bent is called the cartilage. Example: Ear lobe. They are also found in joints.
- Muscles are the flesh on the bone. They bulge due to contraction and becomes shorter, thicker and stiffer. They work in pairs to move a bone. When one muscle contracts to pull a bone in a direction the other muscle relaxes. To move a bone in the opposite direction, relaxed muscle contracts to pull the bone towards the original direction while the first is in a relaxed position.
Different Types Of Joints
Ball And Socket Joint
They are found in the hip area and joints of the shoulder. It allows movements in all directions which can be attributed to its rounded shape. This round end fits into the cavity of the other bone thus allowing the movement.
Pivotal Joint
This joins the head and neck region together. Pivotal joints allow the head to bend backwards and forward and also the left or right movement of the head.
Hinge Joint
It is a common class of synovial joint. They are lubricated with synovial fluids allowing pain-free movement. These joints are usually found in the elbows, ankles, knees, knuckles etc. It favours the back and forth movement.
Fixed Joint
Also known as fibrous joints. They join two bones which are unable to move and are fixed. It helps give a definite structure and keeps it intact. They join the bones in our head and also in the lower arm where the radius and ulna bones meet.
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