Understanding Long Bones: Structure, Definition & Examples

Definition: Regular bones, also known as long bones, are those in which the length is significantly greater than the width and thickness. It constitutes the principal part of the limb skeleton and includes bones such as the humerus, femur, and phalanges.

Structure:

Regular bones have a diaphysis, which is a tubular shaft representing most of the bone's length. At each end of the diaphysis are the rounded epiphyses. The diaphysis is hollow, forming the medullary cavity containing marrow. The outer surface of the diaphysis is covered by a tough membrane called the periosteum.

Growth:

During development, regular bones grow primarily through a process called endochondral ossification. This process involves the growth of cartilage at the epiphyseal plates, which are located between the diaphysis and epiphyses. As new cartilage is formed, it gradually turns into bone, causing the bone to elongate.

Functions:

- The main function of long bone is to provide structural support and protect vital organs.

- They facilitate movement by serving as levers for attached muscles and tendons.

- Long bones also store minerals, primarily calcium and phosphorus, and contribute to blood cell production.