Types of Bones in the Human Body Simplified

There are five different types of bone found in the human body. These bones are mainly  differentiated based on their width to height ratio and shape.

Long Bone

Long bones can actually be long like the femur of the leg or the humerus of your arm. They can also be short like the metacarpals of your hand. The true definition of long bones are:

• Being longer than they are wide.
• Growth plates at either end for longitudinal bone growth.
• Outer surface of compact bone and inner surface of spongy bone (also called cancellous bone).
• Both tips are covered in hyalin cartilage to aid in shock absorption.

Short Bones

Short bones can be found in your wrist and foot. You can consider them to be square shaped bones because:

• They are just as long as they are wide.
• No longitudinal bone growth plates.
• Thin outer surface of compact bone with spongy bone on the inside.

Flat Bone

Flat bones are flat like their name states. Some examples of flat bones are your scapula, sternum(breast plate), ribs, cranium(skull), and os coaxae(hip). Flat bone is:

• Thin bone and not round in comparison to other bones of the body.
• No longitudinal bone growth.
• Thin outer layers of compact bone with spongy bone on the inside.

Sesamoid Bone

Sesamoid bones are the size of short bones but they are located between 2 tendons. An example of sesamoid bone is the patella or knee bone. Sesamoid bone:

• Short, irregular and found between two tendons.
• Has no longitudinal growth.
• Found in locations where a tendon passes over a joint.

Irregular Bones

Irregular bones are called irregular because they can not be categories as long, short, flat, or sesamoid. Some example of irregular bones are the vertebrae, hyoid bone and (tongue attachment). Irregular bone has:

• Thin layers of compact bone with spongy bone on the inside.
• Serve various purposed in the body from protecting the spinal chord, maintaining pharynx and trachea support.

Image Credits

Knee bone by Ulrik