1. Outer- and middle ear (tympanic cavity)
Dr. Csáki Ágnes

2. Outer ear
- auricle
- external acoustic meatus
- tympanic membrane (border)
Tubular canal
Roles:
-to transfer sound waves to the tympanic membrane, to make it oscillate
- help detecting direction

3. Middle ear
- tympanic membrane (border)
- tympanic cavity with the ossicles
- Eustachian tube
To transfer the oscillation of the tympanic membrane to the inner ear receptors

4. Inner ear
- bony labyrinth
- membranous labyrinth
Receptors for hearing and balance

5. incisura intertragica
Auricule
helix
tragus
anthelix
incisura intertragica
ETC.
antitragus
lobulus auricularis
Known inheritance, previously used to identify the father of children.

6. Elastic cartilage (cartilago auricularis)
Rudimentary muscles (mm. auriculares) (innervations: n. VII.)
Originally, the movements of the ear was useful determining the direction of the sound.
(see bats, cats)

7. External acoustic meatus
Cartilaginous and osseous parts
Slightly curved, but could be straightened for the inspection of the tympanic membrane
Glands producing cerumen
Relatively frequent inflammations, especially in small children

8. Somatosensory innervations of outer ear
n. V/3: auriculotemporal n.
n. X: auricular branch
(clinical importance!)
n. VII: (posterior auricular n.), auricular branches (clinical imp.!: Facialis paresis - VZV)
Greater auricular n. (plex. cervicalis)

9. Tympanic membrane Plica mallearis ant.
Plica mallearis post. (chorda tymp.)
Prominentia mallearis
Pars flaccida
Stria mallearis
Umbo membr. tymp.
cone of light
Pars tensa

10. external surface of the eardrum
OTOSCOPIC PICTURE
IV.
Stria mallearis I.
Posterior
side
umbo
III.
Anterior
side
II.
Paries membranaceus

11. the external acustic meatus.
position of eardrum
(FRONTAL SECTION)
External acustic
meatus
Middle
ear
cavity
External acustic
meatus
Right eardrum
Left eardrum
The eardrum makes an acute angle with the inferior and anterior walls of
external acustic meatus and an obtuse angle with superior and posterior walls of
the external acustic meatus.

12. External acustic meatus reaches its entire length by 9th years of age.
otoscope
External acustic
meatus
Eardrum
External acustic meatus reaches
its entire length by 9th years of age.
Foreign objects!

13. Tympanic membrane Cone shaped structure, its surface is 0.7 cm2.
Its colour is pearl gray.
The colour and position of the membrane indicate the change of air pressure in the tympanic cavity or the presence of inflammatory disease.

14. Otitis media

16. Middle ear – ossicles incus malleus (hammer)
Role: to reinforce the oscillations of the tympanic membrane to be able to transfer oscillation to the perilymph of the inner ear – impedance matching
stapes

17. The tympanic membrane oscillates with greater amplitude than the stapes, but due to the differences in surface area the pressure exerted by stapes is much higher (also act as a two armed lever)
Have to transfer the oscillation of air to a fluid, which have a bigger inertia.
(impedance matching)

18. Hammer – malleus Articular surface Head (caput) Lat. process.
Ant. process
Manubrium

19. Incus
Body (corpus)
Articular surface
Long leg (crus)
Short leg (crus)

20. Stapes Head (caput) Crus ant. Crus post.
The base of stapes is fitted to the oval window.
Base

21. Ossicles in situ 1 Sup. malleolar lig. m. tensor tympani
Lat. malleolar lig.

22. Ossicles in situ 2 Lig. incudis sup. Lig. mallei sup.
Lig. incudis post.
Lig. mallei lat.
Ossicles in situ 1
Lig. mallei ant.
Chorda tympani
m. tensor tymp.
n. V/3.
m. stapedius
n. VII.

23. Conductional deafness
otosclerosis
perforation of the tympanic membrane caused by chronic otitis media or trauma

24. tympanic cavity Brick shaped having six walls
It is located in the pyramid
Antero-posterior diameter is longer than
the medio-lateral one and runs parallel
with the long axis of the pyramid
3. Medial and the lateral walls bulge into the cavity,
it is similar to biconcave lens
4. The cavity is open forward and backward

25. Matchbox shape with 6 walls
Tympanic cavity
Air filled cavity, communicating with the pharynx via the Eustachian tube (to equalize the pressures – scuba diving)
Matchbox shape with 6 walls

26. Medial wall (paries labirinthicus)
Prominence of the lateral semicircular canal
fenestra vestibuli (oval window)
Prominence of the facial canal
Semicanalis mi. Tensoris tympani
Antrum mastoideum
Opening of the auditory tube
Tympanic sinus
promontory
Sulcus promontory n. tympanicus (IX)
fenestra cochleae (round window)

27. Lateral wall (paries membranaceus)
Manubrium mallei
Epitympanic recess
Anulus fibrocartilagineus
chorda tympani
Tympanic membrane

28. internal surface of the lateral wall
Epitympanum
Mesotympanum
Hypotympanum
Prussak space

29. Superior wall (paries tegmentalis)
Epitympanic recess
Tegmen tympani
(facial canal)
n. Petrosus major et minor
At the tegmen tympani the osseous wall of the cavity is extremely thin, easily broken in vivo and on the skulls.

30. Anterior wall (paries caroticus)
Auditory tube
m. Tensor tympani
Carotid canal
(aa. Caroticotympanici)
As a developmental defect the internal carotid a. could be inside the cavity

31. anterior wall of the tympanic cavity
Tensor tympani muscle
Tuba auditiva
Canaliculi caroticotympanici
Paries caroticus

32. Auditory tube
Main role: to equalize the pressure on both sides of the tympanic membrane.
When we swallow the levator and the tensor veli palatini contract, thus opening the pharyngeal side of the tube.
Opening is easier if the pressure in the tympanic cavity is higher!

33. Inferior wall (paries jugularis)
Cellulae tympanicae

34. Posterior wall (paries mastoideus)
Antrum mastoideum
(Cellulae mast.)
Fossa incudis
Eminentia pyramidalis
(m. stapedius)
(canalis facialis)
Canaliculus chordae tympani
Any infection penetrating the mastoid cells is difficult to handle without surgical interference.

35. Mastoiditis acuta

37. Posterior wall (paries mastoideus)
Facial canal

38. Great petrosal nerve
Chorda tympani

39. Muscles of the tympanic cavity
m. Tensor tympani
- innervations: n. V/3.
- function: pulls the manubrium of malleus inside, pre-tenses the membrane, thus making it more sensitive.
but: also protects against too loud noises – when contracts strongly, it limits the oscillation of the membrane significantly.
m. Stapedius
- innervations: n. VII.
- limits the movements of the base of the stapes in the oval window – protects against loud noises
Reflexes for the contractions of both muscles: need time to activate – does not protect against a sudden noise.
Mostly limit the transfer of deeper voices – increase signal/noise ratio!

40. auditory ossicles Incudo-malleolar joint Incudo-stapedial joint
malleus 4
incus 6.
stapes 7. 5.
Short limb of incus
Head of malleus
Neck of malleus
Ant. ligament of malleus
Handle (manubrium) of malleus
Ant. limb of stapes
Post. limb of stapes
Lenticular process of incus
Head of stapes
Footplate (base) of stapes
eardrum

41. suspension of auditory ossicles
in the tympanic cavity
Prussak space
Anular ligament
of stapes

42. MOTION PICTURE SHOWING THE MOVEMENT
OF AUDITORY OSSICLES

43. content of the tympanic cavity
Auditory ossicles suspended by ligaments
Nerves (branches of VII., IX., X. cranial nerves, sympathetic fibers)
Vessels: ant. tympanic artery (maxillary art.)
post. tympanic artery (post. auricular → stylomastoid art.)
sup. tympanic artery (middle mening. art.)
inf. tympanic artery (ascending pharyngeal art.)
caroticotympanic arteries (int. carotid art.)
ant. tympanic vein (pterygoid plexus)
post. tympanic vein (stylomastoid v. → retromandib. v.)
sup. tympanic vein (middle mening. v. → sphenoparietal sinus)
inf. tympanic vein (pharyngeal plexus)
Muscles: tensor tympani muscle (V/3)
stapedius muscle (VII)

44. n. auricularis post. n. VII.
Nerves
n. stapedius
n. tympanicus
r. auricularis n. X.
n. petrosus major
VII IX
n. auricularis post. n. VII. X
n. petrosus minor
n. VII.
plexus carotideus
chorda tympani

45. Peripheral facial paresis (Bell’s paresis)

46. Development of the external ear
Auricle:
3 mesenchymal proliferation of 1st pharyngeal arch
3 mesenchymal proliferation of 2nd pharyngeal arch

47. Development of the middle ear
Pharyngeal arches
outer pharyngeal grooves: ectoderm
inner pharyngeal pouches: endoderm

48. Tympanic cavity:
lateral part of 1st pharyngeal pouch
Auditory tube
medial part of 1st pharyngeal pouch

49. Development of the middle ear
Ossicles:
malleus (anterior lig. of malleus) and incus:
from 1st pharyngeal arch cartilage
stapes:
from 2nd pharyngeal arch cartilage
ossicles remain embedded in mesenchyme until the 8th month
Muscles:
tensor tympani:
from 1st pharyngeal arch
stapedius:
from 2nd pharyngeal arch
Tympanic membrane:
ectodermal epithelium of 1st pharyngeal groove
endodermal epithelium of 1st pharyngeal pouch
intermediate mesenchyme (connective tissue)
External acoustic meatus:
from epithelium of 1st pharyngeal groove

50. Vestibulum, sacculus can. Semicirc. Internal acoustic meatus
Facial canal
Vestibulum, sacculus can. Semicirc.
Internal acoustic meatus
Cochlea, n. cochlearis nodiolus
Antrum mastoideum
Stapes, in oval window
Malleus, head
promontory
External acoustic meatus
Middle ear
m. Tensor tympani, tendo
Tympanic membrane

51. Irodalom
Szentagothai J, Réthelyi M: Funkcionális anatómia, Medicina, 1989
Sobota - Atlas of Human Anatomy, 20th edition, Urban and Schwarzenberger, 1993
Guyton, Arthur C - Textbook of medical physiology, 11th edition, Elsevier Inc., 2006
Klinikai felvételek:
A radiológiai felvételek a következő oldalról származnak:
A fénymikroszkópos felvételek a Humánmorfológiai Intézet metszeteiről készültek.