Plate XXVII. — Seats of Operations on Sinuses of Skull 



1. Supraorbital foramen. 2. Seat for opening into frontal sinus. 3. Nasal canthus. 4. Siedanigrotsky's seat of 



operation. 5. Seat of operation on superior maxillar)' sinus. 6. Opening into frontal sinus, recommended by Craig. 



7. Seat of operation on inferior maxillary sinus. 8. Extremity of zygomatic ridge. 9. Infra-orbital foramen. 



10. Nasal peak. 



OP=J" AX=4' MN=4MO RS=i4" BC=2j" CD=i" EF=i-' FG=iJ-2' 



