Diagram of the embryologic development of the AV canal region and the spectrum of AVSD, including partial, transitional, complete, and intermediate forms. Types A, B, and C refer to the Rastelli classification based on the anatomy of the superior bridging leaflet (please refer to the UpToDate topic review on the clinical manifestations of AV canal defects).
Reproduced with permission from: Cetta F, Minich LL, Edwards WD, et al. Atrioventricular septal defects. In: Moss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult, 7th ed, Allen HD, Shaddy RE, Driscoll DJ, Feltes TF (Eds), Lippincott Williams & Wilkins, Philadelphia 2007. Copyright © 2007 Lippincott Williams & Wilkins.
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