Tonsillar ectopia.

The word ectopia, from the Greek, means “out of position”. Tonsillar ectopia is another term for tonsillar herniationAn anatomical state in which the tonsils of the cerebellum protrude, to an abnormal degree, through the foramen magnum at the base of the skull, into the spinal canal. It is commonly referred to as a Chiari malformation., avoiding use of the eponymousA medical term is described as being eponymous when it is the name of a person or a place. The literal translation of the Greek word is “name placed upon”. Most often the name is that of a medical person who first described a condition. Sometimes it may be the name of a place where a disease first developed. Very occasionally it may be the name of a patient who was first recognised as having the condition to which the eponym is applied. term Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described - see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms..