16. External ear, middle ear - tympanic cavity, tympanic membrane, auditory ossicles Flashcards
Identify 3 parts (Blue, Red, Yellow)
Y - External ear
R - Middle ear
B - Inner ear
External ear (Auricle/Pinna)
-> Identify
What is the blood supply of external ear?
Anterior and posterior auricular arteries (<- superficial temporal a.)
Deep auricular artery ( <- maxillary a.)
Innervation of external ear
Auriculotemporal n.
Great auricular n.
Auricular branch of n. X.
Post. auricular branch of n. VII.
What are the 2 parts of External acoustic meatus?
- outer 10 mm: cartilage
- inner 14 mm: bone
What is the blood supply of tympanic membrane?
External mandibular a., internal mandibular a., radier branches from the arteries of the external acoustic meatus
Innervation of tympanic membrane?
Auriculotemporaln. (n.V/3)
What does the roof of tympanic membrane have?
- Hiatus for the canal of the lesser petrosal nerve
What does the anterior wall of tympanic membrane have?
- Semicanal for the tensor tympani muscle
- Semicanal for the auditory tube
- Caroticotymapanic canaliculi
- Petrotympanic fissure (of Glaser)
What does floor wall of tympanic membrane have?
- Tympanic canaliculus
What does medial wall of tympanic membrane have?
- Prominence of lateral semicircular canal
- Prominence of facial canal
- Oval window→foot plate of stapes
- Round window→secondary tympanic membrane (Scarpae)
- Promontory
What does the lateral wall of tympanic membrane have?
tympanic membrane
Identify
One - Anterior wall
Three - . Posterior wall
Four - Lateral wall
Five - Roof
Six - Floor
What are the 3 divisions of tympanic cavity?
- Epitympanum (Recessus epitympanicus/Atticus)
- Mesotympanum
- Hypotympanum
Describe position of Epitympanum (Recessus epitympanicus/Atticus)
- top from upper edge of tympanic membrane
- head of malleus, body of incus
Describe position of Mesotympanum
- at the level of tympanic membrane
Describe position of Hypotympanum
- below from lower edge of tympanic membrane
Name other 2 recesses (not including divisions of the tympanic cavity)
- Recessus membranae tympani sup. (Prussak’s space): neck and head of malleus, lateral process of malleus, lateral malleolar lig.,pars flaccida
- Recessus membranae tympani ant. et post. (Troeltsch’s space)
What is the arterial supply of tympanic cavity?
- Ant. tympanic a. (<- Maxillary a.)
- Sup. tympanic a. (<- Middle meningeal a.)
- Inf. tympanic a.(<- Ascending pharyngeal a.)
- Caroticotympanic aa. (<- ICA)
What is the venous supply of tympanic cavity?
- Middle meningeal vein
- Pharyngeal plexus
What is the sensory innervation of tympanic cavity?
Tympanicn.( <-n.IX.)
Auriculotemporal n. (<- mandibular n.)
N. X.
What is the parasympathetic of tympanic cavity?
from otic ggl. with auriculotemporal n.
What is the sympathetic innervation of tympanic cavity?
from internal carotic plexus
TYMPANIC CAVITY
-> Identify
Name these 3 Auditory ossicles
Connections between the auditory ossicles
-> Name the 2 joints
Incudomallear joint (1): between 2 saddle forms
Incudostapedial joint (Syndesmosis) (2): between lentricular process of incus an head of stapes
What are the 3 Connections between the auditory ossicles
Incudomallear joint (1)
- between 2 saddle forms
- ~5° movement
- tight capsule
Incudostapedial joint (Syndesmosis) (2)
- between lentricular process of incus an head of stapes
Tympanostapedial syndesmosis
- between oval window and footplate of stapes
- annular ligament
Connections between the auditory ossicles
-> Identify
Ant. malleolar ligament (1)
Sup. malleolar ligament(2)
Lat. malleolar ligament
Sup. ligament of the incus (3)
Post. ligament of the incus(4) Annular ligament (5)
Membrana obturatoria stapedis (6)
What are the 2 Muscles of the ear?
- M. tensor tympani
- M. stapedius
Name 2 parts of Auditory tube (Eustachian tube )
cartilagineous and osseal parts
What are the bone and cartilage of Auditory tube (Eustachian tube )
- bones: semicanal for the auditory tube
- cartilage: medial and lateral lamina
Is mastoid process related to ear? How?
- Mastoid antrum → Mastoid aircells
