The Pinna Flashcards
What is the function of the pinna?
Direct sound to the middle ear
The pinna skin is fixed to the ? on the concave side
perichondrium
What separates the scapha from the external ear canal?
anthelix
What is the tragus made of and what does it mark?
A thick cartilaginous plate that marks the lateral margin of the external ear canal
What marks the caudal border of the external ear canal?
antitragus
What anatomically sits between the tragus and the anti-tragus?
Intertragic incisure
What sits rostral to the tragus as the cranial border of the ear canal
Helix
What separates the intertragic incisure from the helix?
Pretragic
What artery forms the lateral, intermediate and medial vascular rami at the base of the convex surface of the pinna?
The caudal auricular artery
What is The caudal auricular artery a branch of?
External carotid
2 main conditions of the pinna in cats and dogs?
Trauma
Neoplasia
Cat fights are a common cause of pinna trauma. What bacteria is a common contaminant?
Pasteurella multocida
Acute trauma injuries of the pinna - how to manage?
Suture repair
What is the physiological cause of an aural haematoma? (2)
Repeated trauma:
- damage to the auricular cartilage
- shearing of the blood vessels within
If an aural haematoma is not treated, what formed?
Granulation tissue
Following granulation tissue with aural haematomas, what leads to chronic changes and ongoing irritation? (2)
Fibrosis
Ossification of cartilage
In cats how to aural haematomas lead to worsened otitis externa
They may deviate medially blocking the external acoustic meatus
Actinic Keratosis:
A) What causes this?
B) What lesions are seen? (2)
C) What could it develop into?
D) Treatment? (2)
A) Ppre-malignant change that may develop following exposure of non-pigmented skin to UV radiation
B) Erythematous and hyperkeratotic
C) SCC (plaque lesion)
D) Pinnectomy, laser therapy, sunblock/UV avoid
Squamous Cell Carcinoma:
A) How does it normally present?
B) Invasive?
C) Met rate?
A) Raise or erosive and painful lesion. Often bleeding/non healing
B) Locally; into auricular cartilage
C) Low
How to stage SCC?
Although low met. Advsed to thorax and LN
SCC:
A) Recommended treatment?
B) Other options? (4)
A) Partial/total pinnectomy
B) Cryosurgery, laser ablation, radiation therapy, chemo
Haemangioma/Haemangiosarcoma:
A) What induces it?
B) Which cats is it seen in?
A) UVB
B) Light coloured
What lesions are seen with a haemangioma? (6)
(colour)
small, benign, raised, alopecic, subcutaneous or dermal lesions, often blue-tinged in colour
Haemangiosarcoma:
A) Growth rate?
B) Circumscribed?
C) Incasive?
D) Where to met?
A) Fast
B) Poorly
C) Locally
D) Lungs or parenchymal organs