Broadly categorizing, the human skeleton provides the functions of support, protection, movement and muscle attachment to the body.
Support: A skeletal support system allows rapid movement, suspends the vital organs, prevents them from crushing each other and maintains the shape of the body, despite vigorous muscle activity.
Protection: Certain delicate and important organs of the body are protected by a casing of bone. The brain in enclosed in the skull, the spinal cord is surrounded by the vertebral column and the heart and lungs are protected by the rib cage. The skeleton protects the organs from distortion and injury that may result from pressure and/or impact. In addition to providing protection of vital organs, the ribcage also takes part in the breathing mechanism.
Movement: In order to produce movement, many bone of the skeleton perform the function of levers. When muscles pull of these levers like bones, movement is produced. The bending of arms is a common example of skeletal movement. The skeleton requires a system of joints and muscles in order to move.
Muscle Attachment: For effective movement to take place, it is important that muscles are securely attached to the skeleton. One end of the muscle must be attached to the part of the skeleton to be moved, while the other must be attached to the part to be held stationary.