The surgical procedure described here consists in the catheterization
of the ventricular recess within the olfactory bulb of the dog, Canis
familiaris. Twelve dogs belonging to three breeds : Greyhound (dolicho
cephalic), Pointer (mesocephalic) and Pekingese (brachycephalic) were
utilized. The olfactory recess lies in the frontal region, at the leve
l of the transverse plane of the zygomatic process of the frontal bone
; its surgical access is perpendicular to the surface of the stop, 5-7
mm (Pointer and Pekingese) to 13-15 mm (Greyhound) rostral to this pl
ane, and 2+/-1 mm from the median plane. The outer and inner plates of
the frontal bone have to be trephined (2 mm and 1 mm diameter, respec
tively) in order to access the olfactory bulb. Free flowing cerebrospi
nal fluid (CSF) indicates that the tip of the needle is correctly situ
ated within the olfactory recess of the lateral ventricle. This techni
que may be used for sampling CSF, for intracerebroventricular administ
ration of substances in physiological, pharmacological and diagnostic
procedures in the dog.