The odontoid process, also called the dens, is a protuberance of the axis. Life-threatening fractures can occur as a result of forces acting on this anatomical structure due to its proximity to the spinal cord and brainstem. The axis shows a peg-like odontoid process that projects itself superiorly from the body. The odontoid process lies anterior to the spinal cord and is used as the pivot for the rotation of the head. The C1 vertebra, carrying the cranium, rotates on this. The odontoid process and anterior arch of the atlas are held together by the transverse ligament of the atlas. This ligament prevents anterior displacement of C1 and posterior displacement of C2. If any displacement of this form would occur the spinal cord can be compromised due to the narrowing of the vertebral foramen.