YR3 20 SSEar Flashcards
Ear - Major Regions
External, Middle & Inner
Ear - External
Auricle & external acoustic meatus
Ear - Middle
Ossicles, tympanic cavity & bulla
Ear - Inner
Cochlea & semi-circular canals
Ear - Disorders that affect convex surface of the auricle; list
1) Alopecia
2) Aural plaques
3) Canine leproid granuloma
Auricle - Pinnal Alopecia; lesion, species
Bilaterally symmetric lesions most severely affecting the convex surface of the distal half of the auricles. Dog - permanent, Cat - Siamese, spontaneously resolves
Aural plaques
Multiple, hypopigmented, exophytic grey-to-white masses grow on the concave surface of auricle. Often, these plaques coalesce to form a large mass.
Canine leproid (lepromatous) granulomas
Several pyogranulomas are present in the subcutis of the convex surface of the external ear
Ear - Disorders that affect the auricular size and shape; list
1) Microtic & Distorted ears
2) Gotch Ear
3) MPS VI
Auricle - Microtic & Distorted Ears; lesion, species, sequelae
Auricle substantially small - Cats & ‘Elf ears’ in goats. Dogs - Impaired hearing
Auricle - Gotch Ear; species; agent
Cattle ear deformity due to infection with Gulf coast tick, Ambyomma maculatum
Mucopolysaccharidosis (MPS) VI
The auricles in the cat with MPS VI are smaller than the normal cat. The bridge of the nose is also broader in the cat with MPS VI when compared with the normal cat
Auricle - Infarction
Due to loss of blood supply e.g. frostbite
Auricle - Hematoma
The concave surface had become convex due to expansion of underlying CT by mixtures of blood and eosinophilic fibrin
Ear - Inflammatory Diseases; list
1) Ceruminous Exudate
2) Otitis Externa
3) Cutaneous dematophilosis
4) Auricular chondritis
5) Canine leproid granuloma
Auricle - Ceruminous Exudate
Bovine, infection with spinose ear tick
Auricle - Otitis Externa
Auricle is thickened, reddened and painful with obvious otorrhea
Otitis Externa; pathogenesis
Increase in ceruminous glands in the dermis > glands dilated and filled w/ inflammatory cells - neutrophils, macrophages, lymphocytes & plasma cells. Inflammatory cells also present in the periadnexal dermis > lymphoid aggregates form nodules in the dermis near the cartilaginous rings of the external acoustic meatus > the overlying epidermis is mildly to moderately thickened (acanthosis) >luminal diameter has been markedly reduced which can further exacerbate the problem of otitis externa
Otorrhoea
Discharge from the ear
Auricle - Cutaneous dermatophilosis
The auricular skin, as well as skin of the muzzle, face, and periocular region, is matted from a severely exudative dermatitis caused by Dermatophilus congolensis
Auricular chondritis
The auricle is thickened and expanded by a chronic inflammatory exudate containing lymphocytes and fewer numbers of macrophages.
Ear - Neoplasm
1) Squamous Cell Carcinoma
2) Melanomas
3) Ceruminous Gland Adenocarcinoma
4) Proliferative, necrotizing otitis externa
5) Nasopharyngeal polyp
Auricle - Squamous cell carcinoma
Auricle ulcerated and covered by a serohemorrhagic crust caused by SCC
Auricle - Melanomas
Highly malignant and believed to be caused by UV irradiation
Proliferative, necrotizing otitis externa
Thick proliferative mass grows from the inner, concave surface of the auricle and extends into the external acoustic meatus
Nasopharyngeal polyp
A small, central bulge of hypoechoic tissue extends from the left tympanic cavity into the nasopharynx, presumably through the auditory tube
Ear - Congenital Disorders
1) External Acoustic Atresia
2) Microtic & Distorted ears
3) MPS VI
External Acoustic Atresia - Congenital, unilateral
Absence or closure of the ear canal
Ear - Disease caused by parasites
1) Gotch Ear
2) Ceruminous Exudate
