A basilar impression is the sinking of the skull on the vertebral column, reason why the cranial base is descended with respect to the upper limit of odontoides. The basic diagnosis is radiologic, and will confirm the presence of basilar impression if, in lateral projection, the odontoid surpasses the posterior edge of the occipital foramen. Magnetic resonance imaging will also rule out the presence of other lesions such as Chiari malformation, syringomyelia, and tumors of the occipital foramen. Often the surgical treatment is recommended, according to the patient's symptoms and if another pathology is associated. In producing basilar impression neurological compression causes, over time, neurological deficits that may be irreversible if not treated surgically in time. Also, fusion of the cervical vertebrae (KlippeFeil Syndrome), which is associated with basilar impression, produces a short neck with limited movements in the cervical spine.