Ear & Eye Flashcards
What are the 3 ossicles from lateral to medial?
a. Malleus: comma shaped
b. Incus: within epitympanic recess
c. Stapes: separates tympanic cavity from perilymphatic space
Describe path of facial nerve in relation to ear canal
Motor innervation
Through internal acoustic meatus > through fascial canal of petrons temporal bone > exists stylomastoid foramen (caudodorsal osseous ear canal) *caudomedial to bulla * > crosses ventral horizonal ear canal»_space; palpebral branch or lingual branch
What nerve is sensory to ear canal?
Vagus n.
What are the names of the margins / cartilages around the external ear canal opening?
a. Cranial: helix
b. Medial: Antehelix
c. Caudal: Antitragus
d. Lateral: Tragus
Where are the 5 major described vessels located associated with ear canal?
a. Great auricular a. > overlies vertical portion (medial to dorsal apex of parotid gland)
b. Maxillary v. + external carotid > ventral to tympanic bulla
c. Retroglenoid v > rostral to osseous ear canal
d. Internal carotid a > medial to bulla
Simplified, describe hearing and balance
a. Hearing: sound waves hit tympanic membrane > [x] by ossicles > + movement of endolymph within cochlea > converted to nerve impulse by organ of Corti > brain via cochlear n.
b. Balance: fluid movement within vestibule and semicircular canals > hair cells (maculae) and detection depends on canal, otoliths of saccule, and utricle
What are 3 parts of inner ear?
a. Vestibule > middle, contains saccule + utricle
b. Cochlea > seashell contains organ of Corti
c. Semicircular canals > 3 (anterior, lateral, posterior)
What is the vascular supply to middle ear? Nerve supply to inner ear?
a. Tympanic a (from maxillary a) + meningeal + pharyngeal vessels
b. Vestibulocochlear > vestibular > semicircular canals > cochlear n > Organ of Corti
What are 3 components of tympanic cavity called and what do they contain?
a. Dorsal: epitympanum (epitmpanic recess), incus, and part of malleus
b. Middle: mesotympanum – 2 membranes covering middle ear chamber, manubrium of malleus, eustachian tube, bone promontory
c. Ventral: hypotympanum – longest, within bulla > communicates with the tympanic cavity proper
- What can actinic keratosis turn into? Which breed or type of cat most likely gets it?
- Treatment for it?
- What is most common feline cutaneous neoplasm?
- Which breeds predisposed?
- List tx options of SCC of ear in cats?
- SCC - white cats
- Pinnectomy or laser surgery; sunblock preventative?
- Basal cell tumor
- Siamese, Himalayan, Persion
- Partial or total pinnectomy; cryosurgery; laser ablation; pinnectomy + vertical canal ablation; radiation; chemotherapy
- Most common cause of para-aural abscess? % incidence?
- Tympanic membrane can be intact up to __% ears with otitis media?
- List radiographic views to evaluate ear.
- Incomplete debridement of epithelial lining of TECA –> 6-11% dogs with TECA
- 71%
- Lateral;
Dorsoventral or ventrodorsal;
Latero 20 deg ventral -laterodorsal oblique;
Rostro 30 deg ventral - caudodorsal open mouth oblique
- List tx options of auricular hematoma
- With cryotherapy, what is recommended # of cycles for max tumor destruction?
- Repeated needle aspirates
Passive drainage
Active drainage
Chronic hematoma - S drainage incision + stures
CO2 laser drainage / ablation
Human fibrin sealant
Drainage + methylprednisolone into cavity w/ or w/o oral systemic steroids - Two
- What % cats have facial palsy pre-op TECA?
- What % have post-op facial n deficits w/ TECA for dog and cat & what % is permanent?
- % risk for hemorrhage? Which vessel usually?
- % cases that get dehiscence?
- What is failure rate of lateral wall resection?
- 8% pre-op cats
- Post-op
Dogs: 13-39% ; permanent 4-13%
Cats: 12-56% ; permanent 28% - 3-14% hemorrhage; retroglenoid v.
- 25% dehiscence
- 42-55% failure rate
- With pinna SCC in cats, what % recur w/ cryotherapy & what is DFI?
- With grade 3 MCT of ear, what is median DFI w/ pinnectomy?
- With complete excision, what is DFI & MST for feline pinna SCC?
- For aural ACA, what is MST if within ear canal vs extensive involvement after surgery?
- 73%; DFI ~184 days
- 5 months
- DFI 19-22 months; MST 800 days
- Extensive involvement: 5 months
Excision and within canal: 30 months
- List 3 routes of middle ear bacteria
- What are the most common organisms causing otitis media?
- List Ddx for tumors of tympanic membrane
- What breed often gets secretory (serous) otitis media?
- External auditory meatus via tympanic membrane
Nasopharynx via auditory tube
Hematogenous - Staph intermedius
Malassezia
Pseudomonas - Ceruminous gland ACA
SCC
Carcinoma
Lymphoma - Cavalier King Charles Spaniels
- List 3 congenital anomalies of inner ear leading to loss of hearing / balance & their associated breeds
- What view is best in cats to look at bullae?
- List 3 alternative diagnostic tools to evaluate middle / inner ear (not the usual tests)
- Collapse of scala media - Dalmatian
Neuroepithelial degeneration - Rottweilers
Changes in organ of Corti - Pointers - 10 deg ventrocaudodorsal view
- CSF
Brainstem Auditory Evoked Responses (BAER)
Impedance Audiometry
- What is recurrence rate of non-endoscopic traction vs endoscopic transtympanic + curettage + steroid (all endoscopic) for polyps?
- What are options (less invasive) for managing middle ear drainage dysfunction?
- Bullae located / bordered by what for VBO surgical approach in cats?
- Prognosis for cholesteatoma?
- 57% vs 13.5% !
- Myringotomy
Tympanostomy tube or “grommets” - Mandibular symphysis
Caudal mandible
Larynx - Guarded - 45-50% recurrence
- What drug can help tx pain after corneal procedures by decreasing ciliary spasm?
- List types of eyelid speculums
- What muscles elevate superior eyelid?
- What muscle lowers inferior eyelid?
- Cycloplegics (atropine)
- Lightweight Barraquer Wire Speculum
Self-retaining Castroviejo speculum - Levator anguli oculi medialis, levator palpebrae superioris, Müller’s, frontalis
- Malaris muscle
- What are 3 causes of ectropion?
- What is general idea of treatment for each?
- What is Euryblepharon?
Breeds seen often?
Treatment?
1 and 2. Excessively long palpebral fissure –> shorten eyelid
Contraction of scar tissue from previous laceration –> V to Y blepharoplasty
Overcorrection from entropion surgery –> V to Y blepharoplasty
3. Enlargement of palpebral aperture secondary to longer eyelids
– Neopolitan mastiffs, Bloodhounds, Newfies, Clumber spaniels
– Pocket technique for permanent medial canthoplasty
- List tx of distichia
- What are the temperatures to avoid with cryo?
- List Ddx of eyelid tumors in dogs. What is most common in dogs? Cats?
- What is it called to have enlargement of Meibomian gland from intraglandular accumulation of meibum secondary to duct obstruction?
- Cryoepilation
Electroepilation - Below −30°C
- Dogs: Meibomian glands (most common), melanomas, squamous papilloma, histiocytoma
Cats: most common - SCC - Chalazion
- What are treatment options for nasolacrimal duct?
- Treatment for tear film deficiency?
- What are the 5 forms of conjunctiva?
- Nasolacrimal flushes and systemic / topical abx therapy
Catheterization conservative flushing
Exploratory dacryocystotomy
Conjunctivorhinostomy - Immunosuppressives (cyclosporine or tacrolimus)
Parotid duct transposition - Palpebral conjunctiva
Conjunctiva of bulgar and palpebral sides of nictitans
Bulbar conjunctiva
Conjunctival fornix
