[Structure of the dog frontal sinus].

The investigation performed in 30 dogs has demonstrated that the frontal bone has an additional "small" frontal sinus. It situates more distally to the known "large" frontal sinus, in the anterior part of the frontal bone. The "small" frontal sinuses on both sides are also separated with a longitudinal septum and communicate with the nasal cavity by means of independent frontonasal canals.