There has been almost no evaluation or discussion of the symmetry of tonsillar ectopia in the medical literature. We measured the degree of left and right tonsillar herniation in 42 pediatric patients with a symptomatic Chiari I malformation and made clinical/radiological correlations. 18% of all patients with tonsillar asymmetry had clinical symptoms or physical findings referable to the inequality of their hindbrain herniation. In addition, 95% of patients with a coexisting syringomyelia had a right cerebellar tonsillar herniation greater than the left. We hypothesize that slight differences in posterior cranial fossa morphology may physically allow for greater unilateral herniation of the left or right cerebellar tonsil, which may be manifested in a patient’s clinical presentation.

1.
Tubbs RS, Elton S, Grabb P, Dockery SE, Bartolucci AA, Oakes WJ: Analysis of the posterior fossa in children with the Chiari 0 malformation (comments). Neurosurgery 2001;48:1050–1055.
2.
Chiari H: Über Veränderungen des Kleinhirns infolge von Hydrocephalie des Grosshirns. Dtsch Med Wochenschr 1891;17:1172–1175.
3.
Nohria V, Oakes WJ: Chiari malformations, hydrosyringomyelia, and the tethered cord syndrome; in Weinstein SL (ed): The Pediatric Spine: Principles and Practice. New York, Raven, 1994, pp 685–705.
4.
Bloch S, Van Rensburg MJ, Danziger J: The Arnold-Chiari malformation. Clin Radiol 1974;25:335–341.
5.
Lee KS, Bae WK, Yoon SM, Doh JW, Bae HG, Yun IG: Location of the chronic subdural haematoma: Role of the gravity and cranial morphology. Brain Inj 2001;15:47–52.
6.
Kennedy DN, O’Craven KM, Ticho BS, Goldstein AM, Makris N, Henson JW: Structural and functional brain asymmetries in human situs inversus totalis. Neurology 1999;53:1260–1265.
7.
Tubbs RS, Salter G, Elton S, Grabb PA, Oakes WJ: Sagittal suture as an external landmark for the superior sagittal sinus. J Neurosurg 2001;94:985–987.
8.
Giedd JN, Snell JW, Lange N, Rajapakse JC, Casey BJ, Kozuch PL, Vaituzis AC, Vauss YC, Hamburger SD, Kaysen D, Rapoport JL: Quantitative magnetic resonance imaging of human brain development: Ages 4–18. Cereb Cortex 1996;6:551–560.
9.
Quisling RG, Quisling SG, Mickle JP: Obex/nucleus gracilis position: Its role as a marker for the cervicomedullary junction. Pediatr Neurosurg 1993;19:143–150.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.