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FRiday is scheduled to be a review day, but we're all behind.....so it's 
likely to be a catch up day.

so. facial.....identify the major veins.

FACIAL NERVE cn VII innervates all the facial muscles and also the caudal 
belly of the digastricus muscle. to find it you dig deeply between 
parotid and sublingual gland. it exits the skull through the stylomastoid 
foramen, near the back of the skull at the base of the ear. there is a 
branch which courses dorsally rostral to the ear, this is the 
auriculopalbebral branch, innervates ear and eyelid muscles. also there 
are branches going to cheek: the ventral and dorsal buccal branches, 
which are dorsal and ventral to the duct of the parotid gland.

three muscles on jaw: masseter, temporalis, and pterygoid -->close jaw
one other muscle on jaw: digastricus ---->opens the jaw. goes from the 
paracondylar process of the skull to its insertion on the body of the 
mandible.
digastricus actually starts as two muscles embryologically and they merge 
into one muscle during development. there is also a rostral belly of the 
digastricus which has a separate innervation.

TRIGEMINAL NERVE cn V: maxillary branch, ophthalmic branch, mandibular 
branch. the MANDIBULAR n comes out of the oval foramen of the skull and 
has an AURICULOTEMPORAL branch. it follows a similar course to the 
auriculopalpebral br of the facial nerve. the OVAL FORAMEN is a bit 
rostral to the STYLOMASTOID FORAMEN.

THYROID GLAND: not much to see, just be able to ID it. basically a single 
lobed structure on the lateral side of the trachea. it's kind of two 
parts connected by an isthmus on the ventral side of the trachea which we 
might not see. the thyroid is lateral to trachea, first 5-6 rings, betw 
trachea and carotids. cranial to the thyroids are the parathyroids, which 
we may or may not see.

COMMON CAROTID AA: -branches into caudal and cranial thyroid branches 
which supply the thyroid, don't worry about finding them. common carotid 
terminates as two branches. the EXTERNAL CAROTID continues cranially and 
the INTERNAL CAROTID which goes up into the brain. The INTERNAL CAROTID 
(IC) has a bulge at its connection to the comm carotid which contains a 
baroreceptor possibly called the carotid sinus. it goes to enter the 
skull through the TYMPANO-OCCIPITAL FISSURE.

the EXTERNAL CAROTID (EC) branches dorsally into OCCIPTIAL A and the 
ASCENDING PHARYNGEAL A, and there is a ventral branch called the CRANIAL 
LARYNGEAL. the next branch - also sl ventral- is the lingual artery, 
wihch goes between the styloglossus m and the hyoglossus m. the next 
branch is the FACIAL A which supplies the lips, nasal area, and which 
branches off rostrallly and goes deep to the masseter m.. there is a 
caudal branch as the EC courses dorsally called the CAUDAL AURICULAR 
branch, and there is another branch called the SUPERFICIAL TEMPORAL which 
goes up behind the eye, but in front of the ear, and then the 
continuation of the EC after that is the MAXILLARY A., which is dorsal to 
the facial a. the maxillary a dives under the jaw joint and heads 
rostrally.

in order to see what else is going on in the head we need to take apart 
the skull. cut rostral auricular mm and pull the ear back caudally. 
remove the temporalis muscle from the temporal fossa (it inserts onto the 
coronoid process of the mandible and at the zygomatic arch.) the area of 
the TMJ is very muscular in the dog and we need to get that muscle out of 
the way. then we need to cut the entire zygomatic arch - remove as MUCH 
of the arch as possible. it will make our lives easier. cut the coronoid 
process off also, as far down as possible.

so, the MAXILLARY a continues on entering the ALAR foramen. it gives off 
an INFERIOR ALVEOLAR A which goes to the mandible and enters the 
mandibular foramen. it gives off two other branches we won't need to 
know: the caudal deep temporal and the middle meningeal which goes into 
the brain. POST-alar foramen the Maxillary a gives off the external 
ophthalmic artery which goes to periorbita. also gives off major and 
minor palatine aa which go to hard and soft palate, also the 
sphenopalatine also goes to palate. then finally, the maxillary artery 
goes into the maxillary foramen in rostral part of skull, then goes 
through infraorbital canal, the opening of which is called the 
infraorbital foramen, and when it comes out it branches into numerous 
smaller aa, and is called the infraorbital artery as it comes out of the 
canal and begins to branch. this is pretty superficial and can be 
palpated in the live dog.

MANDIBULAR NERVE: comes off trigeminal n, cn V, out of oval foramen. we 
know it branches into auriculotemporal branch. the BUCCAL nerve courses 
along near the zygomatic gland and is sensory to the teeeth. there are 
three other branches of mandibular nerve to see. the rostral most is the 
LINGUAL nerve. tucks under the styloglossus muscle. next caudal branch is 
the inferior alveolar nerve which goes w/inf alv art into mandible, and 
is sensory to lower lip and to teeth, and then the most caudal is the 
myelohyoid n which goes to mylohyoideus muscle nd the rostral belly of 
the digastricus, and is motor to mylohyoideus..


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