Because of a lapse in government funding, the information on this
website may not be up to date, transactions submitted via the
website may not be processed, and the agency may not be able to
respond to inquiries until appropriations are enacted. The NIH
Clinical Center (the research hospital of NIH) is open. For more
details about its operating status, please visit
cc.nih.gov. Updates
regarding government operating status and resumption of normal
operations can be found at
opm.gov.
Chiari Malformation Type I with Syringomyelia MeSH Supplementary Concept Data 2025
An autosomal dominant type of Chiari malformation characterized by the protrusion of the cerebellar tonsils through the FORAMEN MAGNUM, defined radiologically as tonsillar descent of 5 mm or more. CM1 is associated with SYRINGOMYELIA in up to 80% of cases. May be asymptomatic or can cause headaches, ocular disturbances, otoneurologic disturbances, lower cranial nerve signs, CEREBELLAR ATAXIA, or MUSCLE SPASTICITY. Onset of symptoms is usually in the third decade of life. OMIM: 118420