Classification of Bones according to shape
- Long bones: Long bones are characterized by a long tubular shaft and an articular surface at each end of the bone where ligaments and tendons attach. They’re found in the limbs to facilitate movement and support the weight of the body. These bones include the major bones of the arms and legs such as the humerus and femur, tibia and fibula, and the radius and ulna.
- Short bones: Short bones are roughly cube shaped and are as long as they are wide. It has no shaft but it contains a spongy substance covered by a shell of the compact. Helps to provide stability and movement within the ankle and wrist joints. They provide little to no movement. Examples of this type of bone include the carpals and metacarpals in the wrists and ankles.
- Flat bones: The primary purpose of this type of bone is to protect internal organs such as the brain, heart, and lungs. It also provides a large surface area for muscles to attach to. Examples of this type of bone include the cranium (skull), the thoracic cage (sternum and ribs) and the ilium (pelvis). These contain two layers of compact bone with a spongy substance in between.
- Irregular bones: This type doesn’t fall in any category e.g. vertebrae and the bones of the face. These bones vary in size and structure with the shape usually being very complex. Irregular bones serve different functions depending on location.
- Sesamoid bones: they are small bones which develop in the tendons of muscles e.g. patella of the knee joint. The function of this bone is to protect tendons and diminish friction and wear on joint surfaces.