The Equine Head Flashcards
palpable bony landmarks of the skull
- facial crest
- zygomatic arch
- supraorbital foramen
- nasoincisive notch
- infraorbital foramen
- mental foramen
- mandible
facial crest
- origin of the master muscle
- transverse facial artery, nerve, and vein run just ventral to facial crest
zygomatic arch
is fully bone in horse
supraoribtal fissure
supraorbital nerve comes there here; block this for eye procedures; this is d to eye fairly medial
nasoincicive notch
notch between nasal and incisive bones around hole in front of skull
infraorbital foramen
this is in maxilla around level of end of facial crest; infraorbital nerve emerges from this
mandible
- TMJ
- Ramus
- Vascular notch
mental foramen
mental nerve emerges form this to provide sensory innervation to lower lip; block this for tooth stuff; this is in mandible v rostral
vascular notch
this is pt of mandible where rounded pt of ramps turns into straight part of jaw bone; facial vein, artery, and parotid duct runs through here
muscles of facial expression innervation
CN VII (facial nerve)
muscles of facial expression
orbicularis occult, orbicularis iris, zygomaticus, levator nasolabialis, levator labii superioris, depressor labii inferioris, and buccinator
muscles of mastications
masseter, temporalis, digastricus, medial and lateral pterygoid msucles
muscles of mastication innervation
mandibular branch of the trig menial nerve (CN V) and digastrics gets additional motor innervation from facial nerve (CN VII)
maseter
big muscle over cheek; attaches from facial crest to mandible
termporalis
muscle of mastication on top of the head
digastrics
muscle on back of chin; attaches to paracondylar process
medial and lateral pterygoids
deep
branches of facial nerve
- dorsal and ventral buccal branches
- auriculopalbepral branch
dorsal and ventral buccal branches
- these are branches of CN VII
- these are visible crossing the surface of the masseter (mid masseter)
- arise as direct continuations of facial nerve emerging from under parotid gland
what do dorsal and ventral buccal branches innervate
they are motor innervation to muscles of facial expression
auriculopalpebral branch innervates
motor to eyelid
trigeminal nerve ophthalmic division
branches into supraorbital nerve which is sensory to eyelid (medial canthus); this nerve emerges through supraorbital foramen
trigeminal nerve maxillary nerve
infraorbital nerve is its continuation
- nerve is entirely sensory
- enters maxillary foramen and passes rostrally through infraorbital canal
infraorbital nerve innervates
upper cheek teeth and gums; small branch continues w/ in bone for upper canine and incision teeth and their gums
trigeminal nerve mandibular branch
gives off inferior alveolar nerve and mental nerve
inferior alveolar nerve location
- runs into mandibular foramen on medial side of mandible, passes rostrally w/ in mandibular canal; gives off mental nerve then continues w/ in bony canal
- one of the terminal branches of mandibular nerve
mental nerve
- emerges from mental foramen (which is deep to labii inferioris)
- arises from inferior alveolar nerve (one of terminal branches of mandibular nerve)
inferior alveolar nerve innervates
- w/ in mandibular canal gives off twigs to check teeth and gums
- after giving off mental nerve continues w/ in bony canal and supplies canine an incisor teeth and their gums
mental nerve innervates
lower lip
main blood supply to head
common carotid artery
first things to branch of common carotid
internal carotid and occipital arteries branch near level of wing of atlas
blood supply to brain
internal carotid and occipital arteries supply brain
common carotid after branching at wing of atlas
(branching at wing of atlas is internal carotid and occipital arteries branching off)
- common carotid becomes external carotid and gives off linguofacial artery
linguofacial artery
- travels on medial aspect of mandible giving off lingual artery
- when becomes lateral to mandible becomes facial artery
lingual artery
goes to tongue
facial artery
can be palpated at vascular notch of mandible; supplies rostral region of head
terminal branches of external carotid
- superficial temporal artery
- maxillary artery
maxillary artery termination
infraorbital artery
transverse facial artery
comes from superficial temporal artery
vasculature of head
draw
arteries on head where you can take a pulse
- facial (under mandible, the one dad likes)
- masseteric (v superficial over masseter)
- transverse facial (the one by the eye)
masseteric artery relationship to dorsal and ventral buccal branches
it is ventral to d and v buccal branches
retromandibular fossa
- ventral to ear and cd to ramus and angle of mandible
retromandibular fossa contains
- Virborg’s traingle
- guttural pouch
- parotid and mandibular salivary glands
- retropharyngeal and cr deep cervical LNs
- external jugular vein
- common carotid artery
- CN IX, V, XII
- thyroid gland
Viborg’s triangle boundaries
- tendon of sternocephalicus
- ramus of mandible
- linguiofacial vein
guttural pouch location
w/ in vibrog’s triangle
salivary glands of the head
- parotid and mandibular
parotid salivary gland location
- ventral to ear
- occupies large part of retromandibular fossa
parotid salivary gland duct path
- travels w/ facial artery and vein medial to mandibule
- becomes ventrally located at vascular notch
- then travels lateral to mandible
parotid salivary gland drains to
opposite the upper 2nd or 3rd premolar
mandibular salivary gland
elongate; medial to parotid salivary gland and angle of mandible
mandibular salivary gland drains to
sublingual caruncle
lymph nodes horse (important ones)
- mandibular
- medial and lateral retropharyngeal
- parotid
- cr deep cervical
mandibular lymph nodes
the only normally palpable LNs in horse; md to mandible under chin
medial retropharyngeal lymph nodes
- medial retropharyngeal are associated with guttural pouch (on floor of guttural pouch) if these swell it can affect swallowing
- lie in lateral groove btwn pharynx and guttural pouch medial external carotid and linguofacial arteries, the digastrics, and the mandibular gland
- more rostral and ventral than lateral retropharyngeal LNs
lateral retropharyngeal lymph noes
- lie on cddorsal surface of guttural pouch near wing of atlas; close to internal carotid artery and vagosymp trunk (more cddorsal than medial retropharyngeal LNs)
parotid lymph nodes
at/ around base of ear
deep cervical LNs
- cr deep cervical, middle deep cerivcal, and cd deep cervical LNs
cr deep cervical LNs
around level of thyroid gland
retropharyngeal nodes drain
nearly all structures of dorso-cd part of head; lymph from parotid and mandibular LNs passes through them before reaching cr deep cervical LNs
important structures of nasal passages
- dorsal, middle, and ventral meatus
- dorsal and ventral nasal conchae
- ethmoid conchae/ turbinates
- choanae, nasopharynx, opening of auditory tube (guttural pouch)
- pharyngeal recess
meatus and conchae relationships
dorsal, middle, and ventral meatus divided by D and Ventral concha; there is a common meatus that is medial and runs between all 3 of the others (its vertical runs length of dorsal nasal meatus to ventral nasal meatus
ethmoid conchae/ turibates
at cd most aspect of nasal passages
choanae
translation from multiple meatuses to one nasopharynx
pharyngeal recess
tube can get stuck if you go too far
pass tube in
ventral nasal meatus because its big and you will miss ethmoid turbinates
conchae
the conchae are the scroll like/ folds things that are made of thin bone?
meatuses
passages?
guttural pouch is a
ventral diverticulum of auditory tube
fx of guttural pouch
beloved to cool arterial blood prior to it supplying the brain
parts of guttural pouch
there is pouch on either side of head and each pouch has medial and lateral compartment
medial and lateral compartment of guttural pouch divided by
stylohyoid bone
Boundaries of guttural pouches
- D boundary= base of cranium (PTB)
- V boundary- pharynx, medial retropharyngeal LNs, and proximal esophagus
- Cd boundary- atlantooccipital jt
- rostral extent- basisphenoid bone
- lateral boundary- digastrics and mandibular and parotid salivary glands
- medially- medial and lateral pouches divided by stylohyoid bone
important vessels and nerves going through guttural pouch
- ext and int carotid arteris
- cd auricular, superficial temporal, transverse facial, and maxillary arteries and veins
- CNs IX, X, XII (V, VII, XI v close by)
clinical correlates guttural pouch
- guttural pouch mycosis
- chondroids from strangles
- temporohyoid osteoarthropathy (THO)
- Guttural pouch tymapny
guttural pouch mycosis
fungal infection in guttural pouch biggest risk of this dx is fatal epistaxis
chondroids from strangles infection
little pus balls; if they access in get collection of balls of pus in guttural pouch
temporohyoid osteoarthropathy (THO)
- proliferation of stylohyoid bone; dnt know pathogenesis; biggest risk= pathogenic fx of this and then can have CN signs
guttural pouch tympany
- more common in younger animals, air builds up in guttural pouches get bulge where virbog’s triangle is
cartilages of the larynx
- cricoid
- thyroid
- arytenoid
- epiglottis
intrinsic muscles of the larynx
- cricoarytenoideus dorsalis
- cricoarytenoideus lateralis
- thyroarytenoideus dorsalis
- cricothyroideus
- arytenoideus transversus
innervation of intrinsic muscles of the larynx motor
recurrent laryngeal nerve except of cricothyroideus which is innervated by cr laryngeal nerve
innervation of intrinsic muscles of larynx sensory
- primarily cr laryngeal nerve
- recurrent laryngeal nerve provides sensory innervation to mucosa cd to glottic cleft
primary blood supply to intrinsic laryngeal muscles
cr and cd laryngeal arteries, branches of cr thyroid artery
hyoid apparatus
consists of. bones that articulate with each other, larynx, and PTB
hyoid apparatus fx
suspends larynx and tongue
muscles that attach to hyoid apparatus
- sternothyroideus
- thyrohyoideus
- sternohyoideus
- omohyoideus
bones of hyoid apparatus
tympanohyoid -> stylohyoid -> remnant of epihyoid -> cerratohyoid -> lingual process of basihyoid -> thyrohyoid
most clinically relevant intrinsic muscle of larynx
cricoarytenoideus dorsals which abducts the arytenoids
Cerritohyoid
can take this away in case of THO
sinuses of horse
- frontal
- conchal (dorsal and ventral)
- maxillary (rostral and cd)
- Sphenopalatine sinus
frontal sinus extend
extends rostrally from level of tempromandibular joint to beyond rostral margin of orbit
frontal sinus continuous with
continuous rostrally with dorsal conchal sinus
conchocrontal sinus
continuous frontal and dorsal conchal sinuses
conchofrontal sinus communicates with
caudal maxillary sinus
conchofrontal sinus and caudal maxillary sinus communication
via the frontomaxillary opening
dorsal and ventral conchal sinuses separated from nasal cavity
by thin dorsal and ventral nasal concahe
dorsal conchal sinus communications/ continuous with
- continuous with frontal sinus
- communicates with maxillary sinus via frontomaxillary opening
ventral conchal sinus communication
communicates with rostral maxillary sinus
maxillary sinus transversed by
infraorbital canal transverses this
maxillary sinus parts
rostral and cd which are separated by bony oblique septum
maxillary sinus communications
rostral and cd maxillary sinuses both communicate with middle nasal meatus via nasomaxillary opening
naso-maxillary opening
rostral and cd maxillary sinus communicate with middle nasal meatus via this opening
infraorbital canal
divides cd maxillary sinus into medial and lateral compartments
medial compartment cd maxillary sinus communicates with
sphenopalatine sinus
rostral maxillary sinus communicates with
ventral conchal sinus over infraorbital canal
caudal maxillary sinus communicates with
conchofrontal sinus via frontomaxillary opening
maxillary sinuses and teeth
tooth roots of last 3-4 cheek teeth project into maxillary sinuses especially in young animals and tooth root infections may result in unilateral sided discharge
sphenopalatine sinus location
sits cd ventral to ethmoid turbinates
sphenopalatine sinus communication
communicates with md compartment of cd maxillary sinus
deciduous teeth formula
303/303
permanent tooth formula
31(3)43/3133
clinical correlates maxillary sinus
tooth root infections/ extractions can result in drainage from nose b/c maxillary sinus and often swelling of maxillary sinus can open up max sinus to extract tooth
hyposdont teeth
continue to grow from alveolar even after occlusal surfaces are in contact (constant wear and eruption)
hyposodont tooth with age
growth is finite as animal ages and wears down its teeth alveolus is filled in and tooth pushed out toward the gingival surface
surfaces of individual tooth
lingual, buccal, and occlusal surfaces
lingual surface
contacts tongue
buccal surface
contacts mucosa of teeth
occlusal surface
contacts another tooth and provide the grinding surface
tooth types in horses
incisors, canines, premolars, and molars
canine teeth in horses
canines usually absent or rudimentary in mares
wolf tooth
first upper premolar; may be removed bc thought to interfere with bit
first lower premolar
usually absent
deciduous incisor eruption time
1st deciduous incisors erupt at 6 days
2nd deciduous incisors erupt at 6 weeks
3rd deciduous incisors erupt at 6 months
permanent incisor eruption
1st permanent incisor eruption 2 1/2 yrs
2nd permanent incisor eruption 3 1/2 yrs
3rd permanent incisor eruption 4 1/2 yrs
deciduous vs permanent incisiors
deciduous incisors are shorter and have narrower neck than permanet
canine teeth erupt at
4-5 yrs
first permanent premolars erupt at
5-6 months
2nd at 2 1/2 yrs
3rd at 3 yrs
4th at 4 yrs
dental cup
- depression in infundibulum and filled with cementum
- located closest to lingual surface
- lost on 1st incisor 6yrs, 2nd at 7yrs, 3rd at 8 yrs
enamel spot
dental cup persists as enamel spot on lingual surface
dental star
depression on labial surface of incisors is indicative o appearance of pulp cavity and appearance on 1st incisor at 8yrs 2nd at 9 yrs 3rd at 10-11yrs
angle of incisors in horses
angle of incisors in profile decrease as horse ages
other changes for aging horses
- angle of incisors in profile decreases
- Galvayne’s groove
- shape change (oval to round to triangle to oval)
oral cavity
cd border is glossopharyngeal arches
lingual tonsil location
on root of tongue and lateral to median glossoepiglotic fold mucosa thrown into irregular elevations w/ small orifices at their apices the deep furrows between elevations are crypts of lingual tonsils
parotid papilla location
this is where parotid salivary gland drains to this is opposite upper 2nd or 3rd premolar
palatine tonsil location
- long
- lies lateral to root of tongue and cd to palatoglossal arch
