Abstract
Following the previous study on the frontal sinus, studies were made on the maxillary, sphenoidal and ethmoidal sinus. Dog's maxillary sinus is not in existence, it is nothing but the cavity grown in inside of the maxillary corpse joining the lamina paphracea of ethmoid. The volume of this cavity is 11.10±1.903 cc in the right, 10.86±2.360 cc in the left. In the dog, the sinus sphenoidalis does not exist. There is seen a recessus and the sphenoidalis in front of the body has not yet taken the shape of cavity.
As for the spongy matter of the interior body, it is absorbed a little, looks rough, and is not open to the recessus sphenoidalis on both sides. The ethmoidal concha is divided into three parts ; frontal concha, original ethmoidal concha and sphenoidal concha. Two frontal concha in the center lead to both A-cavity and B-cavity.
As for the original ethmoidal concha, it is divided into four endoturbinates and six ectoturbinates some growing independently and others in combination. While, sphenoidal concha are two in number both intruding into the recessus sphenoidalis.
