© 2013 Springer Science+Business Media New York. All rights reserved. The symptoms of a Chiari II malformation (CIIM) arise from variable degrees of brain stem compromise and are most commonly manifest as elements of bulbar failure but may involve the long tracts and sensorium as well. Whether this compromise in function arises as a result of inherent brain stem malformation or as a result of physical compression from a malformed posterior fossa remains an active area of debate. Symptoms associated with the CIIM (Table 25.1) are age specific in their presentation and can be subtle or profound. Stridor is the hallmark symptom of symptomatic CIIM in the newborn and represents an urgent neurosurgical need. Impaired airway protection; generalized lethargy, listlessness, and hypotonia; and a variety of gastrointestinal symptoms may also be seen in infants with a symptomatic CIIM. The manifestations of CIIM in the older child and adult are less common, more insidious in onset, and less acutely threatening to survival than in the infant. Progressive dysfunction of the hands (with associated sensory symptoms), sleep abnormalities, and ataxia may be seen in the older child or adult. Symptoms are age related and localize to the dysfunctional bulbar structures of the posterior fossa.