The axial skeleton and the appendicular skeleton are the two divisions of the skeletal system. Skull bones, the hyoid, and the middle ear bones are in the axial system. Also included in the axial skeleton are the bony thorax and vertebral column. Extremity bones, hip bones, and the shoulder girdles make up the appendicular skeleton. Included in the extremity bones are the bones of the fingers and toes.
Human bodies are made of a total of 206 bones. These bones are known as the skeletal system. The skeletal system is the frame of the body, providing support and protecting organs in the body. There are two parts of the skeletal system, called the axial and appendicular skeletons. Each of these two divisions is located in separate sections of the body.
Bones in the skull portion of the axial skeleton are classified into two groups: facial and cranial bones. As one of the divisions of the skeletal system, the axial skeleton consists of the bones of the head, neck, and spine. Air-filled cavities, called sinuses, are located through some of the skull bones. A bone called the hyoid, located in the neck, holds the tongue in place, and three bones are found in the middle ear. Vertebrae are bones that are stacked to form the spinal column, which runs from the back of the skull to the pelvis.
Different types of bones are found in both divisions, and they are categorized based on their size and shape. Long bones are found in the arms and legs. There are also short bones, such as those found in the ankles and wrists. The cranial bones are flat bones. Vertebrae in the spinal column are called irregular bones because they are not shaped like the other types of bones, nor is each vertebra identical to the others.
Sesmoid bones are not generally part of either of the divisions of the skeletal system. The exception is the kneecap. While it is rare to find sesmoid bones with individual people, everyone has kneecaps. Bones called sutural bones are small bones that are located in the suture joints in between the skull bones.
Although the divisions of the skeletal system consist of bones, there are also other aspects that work with the skeletal system. The muscular system is one of these aspects. This system is made of muscles and connecting parts such as cartilages, tendons, and ligaments. Joints allow certain connected bones to move.
