Anatomy Of The Equine Head-ppt Flashcards
What are the facial and trigeminal nerves of the horse prone to?
Easily injured
Name a treatment for facial nerve paralysis
Electroacupuncture
What nerve passes through the mandibular foramen
Trigeminal n
Clin sig of mandibular foramen in horses
Nerve block site for lower dental procedures
Name the 3 nerve blocks pertaining to the face
1) infraorbital
2) mental
3) mandibular alveolar
Which nerve do the infraorbital, mental, and mandibular alveolar nerves branch off from?
Trigeminal
What muscle must you move out the way to do an infraorbital nerve block?
Levator labii superioris m.
What structures does the infraorbital nerve block desensitize?
Upper lip, nose, first upper two cheek teeth
What injury can an infraorbital nerve block be used for?
External nostril lacerations
How do you palpate the mental foramen for a mental nerve block?
Palpate an inch or two caudal to the canines
What muscle must you move out the way to perform a mental nerve block?
Depressor labii inferioris m.
What structures does the mental nerve block desensitize?
Lower lip, canine, and incisors
What type of procedures are mental nerve blocks useful for?
Tooth extractions
How do you find the proper location for a mandibular alveolar nerve block?
Find the intersection point between a line parallel to the masticatory surface of the cheek teeth and lateral canthus
What are some general uses for nerve blocks of the eye?
Opthalmic examination, eyelid lacerations, subpalpebral lavage system
Which nerve block of the eye is the only one that is not supplied by an afferent nerve?
Auriculopalpebral nerve block is supplied by the palpebral branch of the facial nerve
Purpose of the supraorbital nerve block?
Prevent sensation to upper eyelid
How would you palpate the location for the supraorbital nerve block?
Palpate with 3 fingers between the dorsal rim of orbit and supraorbital fossa
What nerve is blocked during a supraorbital nerve block
Supraorbital branch of the opthalmic nerve which is a branch of the trigeminal nerve
Location of the auriculopalpebral nerve block
Dorsal edge of the zygomatic arch
Why would you perform an auriculopalpebral nerve block
Prevent blepharospasms
What are the main and specific nerves that are affected by the auriculopalpebral nerve block
Main= Facial n.
Specific= Palpebral n.
Location of the lacrimal nerve block
Dorsolateral 1/3 of orbit
What main nerve and its branch supply the lacrimal nerve block
Main: trigeminal n.
Branch: Opthalmic
What is the main nerve and its branch that supply the zygomaticofacial nerve block?
Main: trigeminal
Branch: zygomatic
How do you perform a zygomaticofacial nerve block
Insert needle laterally, along ventral margin of orbit, medial to zygomatic process of frontal bone
Main nerve and branch that supply the infratrochlear nerve block
Main: trigeminal n.
Branch: opthalmic n.
How would you perform an infratrochlear nerve block
Insert needle medially on dorsal orbit
(Palpate trochlear notch)
What can the false nostril be used for
To direct nasogastric tube/endoscope into true nostril
Location of nasolacrimal duct opening
True nostril
Clin sigs of nasolacrimal duct opening
- can be blocked by polyps
- tears come through duct
- used in NLD Jones test
- used to test for corneal ulcers
What connective tissue surrounds the vomer bone and helps make up the nasal septum
Hyaline cartilage (divides left and right nostrils)
Clin sig of nasal septum
Deviation of nasal septum
Name the 3 types of nasal conchae and their clin sig
1) dorsal
2) ventral
3) ethmoid
Clin sig: can be injured and cause hemorrhaging during NT intubation
Name the 3 nasal meatuses
1) dorsal
2) middle
3) ventral
Clin sig of the ventral and common meatuses
Nasogastric intubation and endoscopy
Clin sig of ethmoid conchae
Ethmoid hematology & nasal bleeding
Function of nasal sinuses
Reduce weight of skull & provide expanded spaces for teeth
Epithelium that lines paranasal sinuses
Ciliated, glandular
Define paranasal sinuses
Gas filled cavities between internal and external plates of flat bones of the skull
Name the paranasal sinuses
1) conchofrontal
2) maxillary
3) sphenopalatine
Location of the sphenopalatine sinus
1) caudal to ethmoid conchae
2) dorsal to medial medial guttural pouch
Clin sig of the false nostril
Cover while placing a NG tuber/edndoscope to help guide into true nostril
Clin sig of Nasolacrimal duct
- NLD Jones test (corneal ulcers; patency test)
Injuries assc w/ ethmoid concha
- ethmoid hematoma
- nasal bleeding
Function of paranasal sinuses
- reduce wt of head
- provide space for teeth
3 paranasal sinuses
- conchofrontal
- maxillary
-sphenopalatine
Name of septum that divides rostral & caudal maxillary sinuses
Bony septum
Caudal portion of dorsal nasal conchae communicates w/
Frontal sinus
(Conchofrontal sinus)
Caudal portion of ventral nasal conchae communicates with
Rostral portion of maxillary sinus over infraorbital canal
Sphenopalatine sinus communicates w/
Caudal maxillary sinus, then drains into nasal cavity via middle nasal meatus
Both ends of maxillary sinus drains into nasal cavity via
Nasomaxillary fissure
4 borders of maxillary sinus
Ventral: facial crest
Dorsal: line from infraorbital foramen to medial canthus of eye
Cranial: line from rostral point of facial crest to infraorbital foramen
Caudal: rostral part of bony orbit of eye
How to surgically access maxillary sinus
- incise line from infraorbital foramen to medial canthus
(Avoid infraorbital canal & nasolacrimal duct)
Roots of which cheek teeth are located in the maxillary sinus
Last 3 cheek teeth (PM 4 may be partially located in rostral part)
Clin sig of the sphenopalatine sinus
Infections in young horses goes through plate and spreads to brain bc plates aren’t fused
Location of sphenopalatine sinus
- caudal to ethmoid conchae
- dorsal to guttural pouches and nasopharynx
Surgical approaches to access maxillary sinus
- bone flap surgery
-trephination (2-3 days, replace w/ same bone, flush out until clean)
Function and origin of guttural pouches
- function: influence BP in internal carotid, cerebral blood-cooling mech. during racing, balance system)
- extension of eustachian tubes
What are guttural pouches
- air filled diverticula separated by thin septum
- lined w/ respiratiory epithelium including goblet and mucus cells
What divides guttural pouches into medial and lateral parts
Stylohyoid bone
T or F: lateral guttural pouch is larger than medial
False; medial is larger. Lateral is 1/3 of the size
3 natural entrances to the guttural pouches
1) nasopharynx (endoscopy)
2) lateral canthus
3) dorsal to pouch
Contents of the medial guttural pouch
- internal carotid a.
- CN IX, X, XII
Contents of Lateral guttural pouch
- External carotid a.
-maxillary V.
List diseases of guttural pouches
- tympani
-empyema
-mycosis
-exostosis of stylohyoid bone
- tumors
Surgical approaches of guttural pouches
- modified whitehouse (enter ventral medial compartment)
- viborg triangle
Borders of viborg triangle
Cranial: ramus of mandible
Caudal: tendon of sternocephalicus
Ventral: linguofacial v.
What two structures do you tie together during a tie back surgery
Muscular process of arytenoid cartilage and dorsal aspect of cricoarytenoideus m.
Clinical cases assc w/ larynx, soft palate, and epiglottis
- laryngeal hemiplegia
- epiglottic entrapment
- dorsal displacement of the soft palate
Instrument used during laryngeal ventriculectomy/sacculectomy
Surgical burr
Another method of performing a laryngeal ventriculectomy is
Via laser
Treatment for laryngeal hemiplegiaa
Laryngeal ventriculectomy
Treatment & tool for epiglottic entrapment
Pulling tissue down w/ broncho-esophageal forceps
