Absence of a Foramen of Magendie in the Dog, Cat, Rabbit, and Goat

Abstract

THE MOST recent monograph devoted to the anatomy of the cerebrospinal fluid pathways¹ states that, "The position as to the presence or absence of the foramen [of Magendie] in the animal kingdom as a whole is somewhat obscure..." We report here a study in which the brains of the dog, cat, rabbit, and goat were serially sectioned in the sagittal plane. Microscopic examination showed that the foramen of Magendie was absent in all four species. Procedure Whole brains from three dogs, three cats, and two rabbits were removed after killing the animals by overdosage with pentobarbital, the cranium remaining fixed in a stereotaxic holder. All animals were adults. In six the entire brain and meninges were perfused by gravity first with saline and then with 8% formaldehyde solution, using a glass cannula inserted through the heart into the aorta (the last dog and all cats and rabbits). Two goat heads