Arnold-Chiari malformation or Chiari malformation (CM1) is the name of a group of deformities of the posterior fossa and hindbrain (cerebellum, pons and medulla oblongata). The pathogenetic basis of this disease is associated with herniation of the cerebellar tonsils through the foramen magnum. CM1 is classified as a rare disease. CM1 can present with a wide variety of symptoms, also non-specific, with consequent controversies on diagnosis and surgical decision-making, particularly in asymptomatic or minimally symptomatic. Syringomyelia (Syr), hydrocephalus, craniocervical instability, encephalocele, scoliosis, spina bifida and spinal dysraphism are the most common comorbidities that may present at the time of diagnosis or develop secondarily. Most attention has been paid to syringomyelia complicated by CM1 (CM1-related Syr). Formation of single or multiple fluid-filled cavities in the spinal cord and/or bulb as a result of pulse changes in intracranial pressure associated with disruption of normal cerebrospinal fluid circulation due to morphological abnormalities of the brain at the magnum level. This condition can be complicated by a rarer disease caused by the development of damage to the anterior horns of the spinal cord - amyotrophic sclerosis (ALS syndrome). In this brief literature review we are trying to demonstrate the mean pathogenic basis of amyotrophic lateral sclerosis in patients with chiari 1 malformation associated syringomyelia.