External/Internal Ear & Guttural Pouch Flashcards
What are the cartilage/bony processes found in the external ear? (Start proximal and work distally)
Auricular cartilage
Annular cartilage
Bony process of the acoustic meatus
What is the correct term for the ear canal?
External auditory meatus
How many muscles are in the ear? What are the 3 groups and what do they do?
18
Pre auricular - move ear forward
Post auricular - move ear caudal/medial
Ventral auricular - move ear centrally
What is the motor and sensory supply to the ears?
Sensory - ariculotemporal branch of trigeminal
Motor - rostral, caudal and great auricular nerve
The middle ear is a cavity found within which bone?
Temporal
The middle ear contains the tympanic membrane and tympanic bulla. Which nerves supply this area?
Facial nerve Chordae tempinae (Branch from facial nerve)
Where does the auditory tube run from? What happens to it when swallowing or yawning?
Nasopharyngeal
The entrance is forced open and air enters the middle ear cavity, balances pressure on either side of tympanic membrane
What it is the opening to the auditory tube called? (Opens when yawning/swallowing)
Ostia
The function of the guttural pouch is not known (suggested same as rete mirabile, cool blood). What is the guttural pouch?
An air filled ventral diverticulum of the auditory tube
In which species is the guttural pouch found?
Equidae only
The guttural pouch can hold 300-500ml of air. It is divided into lateral and medial compartments by which bone?
Stylohyoid
What is the guttural pouch near? (Careful when operating)
Carotid artery
Vagus nerve
Maxillary nerve
Pharyngeal lymph nodes
How does the guttural pouch drain? Why?
When head is down and horse swallows (e.g. eating- haynets?)
Ostia is dorsal to the pouch when head is upright
What it is the name of the triangle of area used when surgically approaching the guttural pouch?
Viborg’s triangle
Across bottom of jaw, to neck
What diseases are associated with the guttural pouch?
Tympanic (air distension)
Empyrean (bacterial infection)
Mycosis (fungal infection, causes artery erosion, nose blood, fatal)
