Page 132 - Manual of Equine Field Surgery
P. 132
128 HEAD AND NECK SURGERIES
I·
Conchofrontal sinus
Rostral maxillary sinus Caudal maxillary sinus
7:Jler-,v:,t;_.£a,,;1e, -,.
Figure 21-1 Lateral view of skull with bone removed over the frontal and maxillary sinuses. Note position of infra-
orbital canal and nasolacrimal duct (dotted lines).
a point halfway between the infraorbital foramen
and the orbit at the approximate level of the fifth
cheek tooth. The caudal limit is at the level of the
caudal border of the orbit. The lateral extent is
near the level of the medial canthus. The medial
extent is on midline. In the horse, the dorsal
conchal sinus has an extensive communication
with the frontal sinus, and together they are com-
monly referred to as the conchofrontal sinus. The
rostral extent of the conchal sinus is at the level of
~ Conchofrontal the facial tubercle.
sinus The caudal maxillary and frontal sinuses
lnfraorbital
canal communicate through a large frontal maxillary
opening and drain into the nasal cavity through
, Caudal maxillary the nasomaxillary opening in the middle meatus.
\ sinus
' ...;.;.- Rostral maxillary The rostral maxillary sinus drains into the nasal
sinus cavity through a separate opening in the middle
meatus.
I Facial
I tubercle
PROCEDURE AND PREPARATION
~- Nasolacrimal
ii , duct Several sites are recommended for sinus trephina-
tion in the horse. The trephine portal for the
frontal sinus is 3 to 4 cm caudal to the most rostral
aspect of the frontal sinus and 3 to 4 cm lateral to
midline. The trephine portal for the caudal max-
illary sinus is 1 to 2 cm dorsal to the facial crest
and 7 to 8 cm caudal to the most rostral aspect of
the facial crest. The trephine portal for the cranial
~.Q(l),-::,d~~ maxillary sinus is 1 to 2 cm dorsal to the facial
crest and 3 to 4 cm caudal to the facial tubercle.
Figure 21-2 Overview of skull with bone removed
over the frontal and maxillary sinuses. Note relative As the septum dividing the maxillary sinuses is
positions of infraorbital canal and nasolacrimal duct variable, these locations are guidelines only.
(dotted lines). The infraorbital foramen and the levator
nasolabialis and levator labii maxillaris muscles