1. Sinus disease Veterinary Clinics: Equine Practice
David E Freeman, MVB, PhD 
Veterinary Clinics: Equine Practice 
Volume 19, Issue 1, Pages (April 2003)
DOI: /S (02)

2. Fig. 1
Anatomy of the right paranasal sinuses and nasal passage in a transverse section through the second molar (110) as viewed from the front. 1=frontal sinus; 2=dorsal conchal sinus; 3=rostral maxillary sinus; 4=ventral conchal sinus; 5=dorsal meatus; 6=middle meatus; 7=nasolacrimal duct; 8=ventral meatus. Arrow points to opening from the rostral maxillary sinus to the middle meatus.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

3. Fig. 2
Image of the head of an American Miniature Horse obtained by computed tomography. The extent of the abscess in the frontal sinus and the dental distortion could not be seen on standard radiographs.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

4. Fig. 3
View of the left caudal maxillary sinus and sphenopalatine sinus obtained by direct endoscopy. Rostral is to the bottom of the view. SPS=sphenopalatine sinus; CMS=caudal maxillary sinus; IOC=infraorbital canal. Arrowheads point to the caudal edge of the frontomaxillary opening.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

5. Fig. 4
View of an ethmoid hematoma in the left sphenopalatine sinus obtained by direct endoscopy. The probe was inserted through a separate portal in the caudal maxillary sinus. Rostral is to the bottom of the view. CB=caudal bulla of the ventral conchal sinus. Arrowheads point to the caudal medial edge of the frontomaxillary opening.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

6. Fig. 5 Purulent material draining from the middle meatus.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

7. Fig. 6
Radiographic appearance of an ethmoid hematoma in the right sinuses of a 28-year-old Thoroughbred gelding. An ethmoid hematoma had been removed from the left sinus when the horse was 12 years old (arrow indicates wire sutures used for flap repair). Fluid lines are also evident.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

8. Fig. 7
Intraoperative view of the left sinuses (rostral to the right) through a large frontonasal bone flap in a horse with an ethmoid hematoma (2). The hematoma was covered by a shell of bone that was removed to reveal the lesion. 1=reflection of dorsal nasal concha; 3=ethmoidal labyrinth; 4=caudal maxillary sinus seen through the frontomaxillary opening; 5=rostral maxillary sinus and infraorbital canal.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

9. Fig. 8
Longitudinal section of the head of a horse that had an ethmoid hematoma removed years previously (note deformed sinus architecture rostrally to the right). Arrowheads indicate lesion remaining in the sphenopalatine sinus that caused persistent clinical signs.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

10. Fig. 9
Commercially available catheter for injection of intralesional formalin of ethmoid hematomas (Cook Veterinary Products, Spencer, IN).
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

11. Fig. 10
Different homemade catheters for injection of intralesional formalin of ethmoid hematomas with 18-gauge needles secured in thick-walled tubing and part of the needle and hub used for the injection port (top). For one system, a sharp bevel has been cut in the thick-walled catheter for injection of the mass. Bar=1 cm.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

12. Fig. 11
Method of injecting formalin into an ethmoid hematoma (black arrowheads) in the right sinuses. The 18-gauge needle was inserted through the trephine hole beside the scope, and some formalin droplets can be seen escaping from the mass. White arrowheads indicate the frontomaxillary opening.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

13. Fig. 12
Endoscopic appearance of an ethmoid hematoma in the left nasal passage (arrowhead) at 1 month after injection with intralesional formalin. Note the shriveled appearance of the lesion and the large size of the ethmoturbinate region. This lesion recurred 12 months later and responded to a single injection then.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

14. Fig. 13
Longitudinal section of a horse's head to show part of an ethmoid hematoma in the right nasal passage (1) connected by a stalk (white arrowheads) that passed through a slit in the dorsal conchal sinus to the larger part of the lesion in the sinuses (2). 3=dorsal conchal sinus cut to expose the sinus cavity; 4=ethmoidal labyrinth. Any treatment directed at the nasal portion of the lesion might fail to destroy the sinus portion.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

15. Fig. 14
Fragments of a sinus cyst with typical loculations encased in bone and sinus lining. Bar=1 cm.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

16. Fig. 15
Oblique radiograph of a depression fracture into the frontal sinuses.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

17. Fig. 16
(A) Open fracture of the sinuses with collapse of the floor of the orbit into the sinus cavity and prolapse of the third eyelid. (B) Same fracture 2 weeks after repair. Note that the wound had to be extended to gain access to the floor of the orbit and fracture fragments.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

18. Fig. 16
(A) Open fracture of the sinuses with collapse of the floor of the orbit into the sinus cavity and prolapse of the third eyelid. (B) Same fracture 2 weeks after repair. Note that the wound had to be extended to gain access to the floor of the orbit and fracture fragments.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

19. Fig. 17
A fracture into the frontal sinus extending the width of the face between the orbits and depressed into the sinus cavity (same horse as in Fig. 15). Arrows indicate the fracture line that is intact to form a hinge for the depressed segment (rostral is to the right). Note the skin flap used to expose the fracture.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

20. Fig. 18
Same fracture as in Fig. 17 repaired by wires after the depressed bone was pried into position by Steinmann pins inserted in the nasal passages. Final cosmetic appearance was good.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

21. Fig. 19
Approaches to the sinuses through a frontonasal bone flap (broken line in A) and maxillary bone flap (broken line in B). 1=rostral maxillary sinus; 2=caudal maxillary sinus; 3=ventral conchal sinus; 4=sphenopalatine sinus; 5=frontal sinus; 6=ethmoidal labyrinth; 7=frontomaxillary opening; 8=dorsal conchal sinus. The conchofrontal sinus (5 and 8 combined) is outlined with a solid line.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

22. Fig. 20
Typical large frontonasal flap. In this case, the packing was brought out through the trephine hole, which was also used for flushing the sinus.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

23. Fig. 21
Method of placing incisions in the skin (solid line) and periosteum (broken line) so that the soft tissues overlap the bone incision.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

24. Fig. 22
Use of a chisel or osteotome to cut bony attachments to the underside of the bone flap.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

25. Fig. 23
Method of prying up the edges of the flap with osteotomes or periosteal elevators to start the elevation.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

26. Fig. 24
Method of using the fingers to pry up the edge of the flap to complete its elevation while using the thumbs to force the fracture at the desired point on the dorsal midline. If the flap is not freed adequately, resistance to elevation can be sensed more easily through the fingers and thumbs than if it were elevated to the point of fracture with instruments.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

27. Fig. 25
Method of packing the paranasal sinuses. Stockinet with the closed end placed in the sinuses and nasal passages as described. This “sock” is then packed with gauze in accordion fashion until it is filled.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

28. Fig. 26
Depression medial to the eye on a horse that had a sinus flap in which the bone was discarded.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

29. Fig. 27
Endoscopic view of the right nasal cavity of a horse that had a frontal flap 2 years previously to remove an ethmoid hematoma. Note the large communication with the sinus cavity and the fungal-like plaque of diphtheritic membrane on the underside of the healed flap.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )

30. Fig. 28
Limited access to the ventral conchal sinus through the maxillary flap (broken line) in a young horse (top) compared with an old horse (bottom). Arrow indicates route over infraorbital canal and cheek teeth into the ventral conchal sinus, which can be the site of infection and cyst formation.
Veterinary Clinics: Equine Practice  , DOI: ( /S (02) )