The human body has 206 bones ranging in size from the femur, the longest, to the stapes, the smallest. Bones are differentiated as long, short, flat or irregular. Bones are made of layers--the periosteum, or outer surface, and the compact bone which contains the cancellous bone. The bone marrow is protected in the center of the bone, where blood cells originate.
Femur
The femur, the longest bone in the human skeletal system, is also known as the thigh bone. It extends from the hip joint to the knee. The head of the femur fits into a ball and socket joint at the hip.
Tibia
The tibia is a thick bone located in the front of the lower leg. Also known as the shin bone, the tibia articulates with the femur above and the talus (ankle bone) below.
Fibula
The fibula is a thin bone on the side of the lower leg. It articulates with the tibia from the knee at the top and the ankle at the bottom.
Humerus
The humerus is the bone between the shoulder and elbow. It is also known as the upper arm bone. It is the fourth longest bone in the body.
Ulna
The ulna is the larger bone of the forearm. Located between the wrist and the elbow, it is on the little finger side of the arm.
Radius
The radius is the slightly smaller of the two bones of the forearm. It is located on the thumb side of the forearm.
Stapes, Incus and Malleus
The stapes, incus and malleus are collectively known as the ossicles--the tiniest bones in the body. Located in the middle ear, the ossicles are responsible for transferring vibrations of the eardrum to the inner ear. The malleus, shaped like a hammer, is attached to the eardrum. The incus, shaped like an anvil, transfers the vibrations from the malleus to the stapes. Once the stapes, shaped like a stirrup, receives the vibrations, it sends the vibrations to the inner ear.
Vertebrae
A total of 33 vertebrae make up the spine, or vertebral column. Each vertebrae is identified by the location in the vertebral column. The cervical spine is comprised of 7 vertebrae and are named C1 to C7, starting where the spine and head attach. The next 12 vertebrae make up the thoracic spine and are named T1 to T12, continuing down the spine. The lumbar region is L1 to L5. Five fused vertebrae comprise the sacral area and are identified as S1 to S5. The coccygeal, or tailbone segment, is fused and makes up the remaining vertebrae.
