What are the Four Types of Bone in the Body?

Our bones offer structure to our bodies. A human adult’s skeleton contains 206 bones. These include the spine’s vertebrae, ribs, arms, and legs. Bones comprise specialised bone cells and connective tissue that has been calcium-fortified. The majority of bones include bone marrow, which produces blood cells. Bones work together with muscles and joints to hold our bodies together and facilitate movement. 

We are talking about the musculoskeletal system. The skeleton shapes and supports the body while protecting vital internal organs such as the heart, lungs, and brain. Our bones contain the majority of the calcium in our bodies. Bone tissue gets formed constantly. The skeleton serves as the body’s structure. It assists in creating our shape and acts as the support system for other components. The 206 bones that make up the skeleton are divided into four categories: long, short, flat, and irregular. Each kind of bone performs a particular job, and some bones serve many purposes. This article discusses the four types of bones in detail.

1. Long Bones

Most arm and leg skeletons contain long bones. Long bones earn their name because they are longer than they are wide. The long bones of the arm include the humerus, radius, ulna, metacarpals, and phalanges. The long bones of the leg include the femur, tibia, fibula, metatarsals, and phalanges. Clavicles are also considered long bones (collar bones). 

Our long bones offer the leverage to move our bodies and impact our surroundings. All long bones comprise two primary components: the diaphysis and the epiphysis. The main body of the long bone is called the diaphysis. The medullary cavity, a hollow space at the centre of the diaphysis, is a tubular structure (or marrow cavity). The diaphysis wall is made of dense, strong bone that is compact. Throughout a long bone’s life, yellow bone marrow fills the diaphysis in the centre. Fat, commonly known as adipose tissue, makes up the yellow bone marrow. An epiphysis can be seen at either end of a long bone. 

At a junction known as a joint, each epiphysis gets formed to fit its connecting bone, and the function of the joint affects the epiphysis’ shape. The proximal (closer to the body) epiphysis of the humerus and the proximal epiphysis of the femur are the rounded heads that resemble half of a ball.

2. Short Bones

Short bones get their name from the fact that they are about as wide as they are long. Diaphysis does not exist in short bones. It comprises the solid bone surrounding spongy bone, just like the epiphysis. Short bones can also contain red bone marrow. There are 32 short bones in the human skeleton. The intricate wrist and ankle joints are made more mobile and stronger by the sliding and shifting action of short bones against one another.

3. Flat Bones

Flat bones serve as the body’s armour. Flat bones give the foundation for the shoulder and hip and the shape of the head and torso. Furthermore, flat bones may protect the delicate tissues beneath. Flat bones, like short bones, have compact bone walls and a sandwich-like middle of spongy bone.

4. Irregular bones

Bones that are neither long, short, nor flat are considered unusual. The forms of these bones have highly specialised purposes. Both the vertebrae in the spinal column and the face bones are atypical. These bones have peculiar forms that are unique to their purpose.


Bones comprise the human skeletal system. They are divided into various groups based on shared traits such as shape, location, and other characteristics. Human bones have various essential roles in the body. They are responsible for movement, upright posture, structural outline, and somatic rigidity. Because of their rigidity, bones primarily “protect” internal organs and other body structures. If you face any bone related health issue, contact Victorian Bone & Joint Specialist for help. 

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