Also known as Arnold-Chiari Malformations, this disorder refers to a set of anomalies of the base of the skull and cervical spine. It occurs when the brainstem and cerebellum are forced to protrude down into the spinal canal through the hole at the base of the skull. Symptoms can vary from irritating to disabling and may include pain in the arm, decreased sensation in the arms or hands, difficulty in walking, headache and neck pain, swallowing difficulties and/or hoarseness.
Although what causes Chiari malformations is unknown, it may be a result of trauma to the skull or may simply be present at birth. Surgery is recommended to decompress the area and relieve pressure on the cerebellum. This can be accomplished by removing a small portion of the skull to provide extra room for the brainstem and cerebellum, or insertion of a shunt to drain accumulations of spinal fluid within the spinal cord.