Low-lying tonsils

Low-lying tonsils, sometimes also called benign tonsillar ectopia, is a subtype of cerebellar tonsillar ectopia denoting asymptomatic and only slight downward descent of the cerebellar tonsils through the foramen magnum and is distinct from Chiari I malformations. Typically a descent of less than 3-5 mm is used, however, this varies from author to author, and is discussed further in the article on Chiari I malformation.

Low-lying tonsils are the preferred term over benign tonsillar ectopia as not all individuals with <5 mm tonsillar ectopia are asymptomatic .

The terminology of caudally displaced tonsils is discussed in the article on cerebellar tonsillar ectopia.