Position of human cervical vertebrae (shown in red). It consists of 7 bones, from top to bottom, C1, C2, C3, C4, C5, C6, and C7.

The Axis (C2 vertebra) also known as epistropheus forms the pivot upon which the first cervical vertebra (the Atlas), which carries the head, rotates. The axis is composed of a vertebral body, heavy pedicles, laminae, and transverse processes, which serve as attachment points for muscles

The atlas is the topmost vertebra and, with the axis (the vertebra below it), forms the joint connecting the skull and spine. The atlas and axis are specialized to allow a greater range of motion than normal vertebrae. They are responsible for the nodding and rotation movements of the head

The sacrum is a shield-shaped bony structure that is located at the base of the lumbar vertebrae and that is connected to the pelvis. The sacrum forms the posterior pelvic wall and strengthens and stabilizes the pelvis.

The fibula is a long bone in the lower extremity that is positioned on the lateral side of the tibia. The fibula is much smaller and thinner than the tibia. It is located just behind the tibial head at the knee joint and then runs down the lateral aspect of the leg until it reaches the ankle joint.

The tibia is one of two bones that comprise the leg.[1] As the weight-bearing bone, it is significantly larger and stronger than its counterpart, the fibula. The tibia forms the knee joint proximally with the femur and forms the ankle joint distally with the fibula and talus.

The linea aspera is the rough, longitudinal crest on the posterior surface of the femoral shaft. Most orthopedic surgeons depend on the linea aspera as an intraoperative landmark identifying the true posterior aspect of the femur.