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1. ANATOMY
OF EAR

2. • EAR
• EXTERNAL EAR
• MIDDLE EAR
• INNER EAR

3. EXTERNAL EAR
• AURICLE OR PINNA
• EXTERNAL AUDITORY CANAL

4. PINNA
• Single piece of yellow elastic cartilage
covered with Perichondrium and skin
(except lobule and outer part of external auditory canal)
• Attached to the side of skull by ligaments
and muscles (supplied by facial nerve),
• Muscles are not well developed in human

5. • HELIX
• The prominent rim of the auricle is
called the helix.
• Anti Helix
• Another curved prominence parallel with and in front of the
helix is called the antihelix.
• Concha
• the antihelix describes a curve around a deep, capacious cavity
Concha, the upper part cymba conchae, and the lower part cavum conchae.
• Tragus
• small pointed eminence In front of the concha, projecting
backward over the meatus.

7. PINNA Contd.
• INCISURA TERMINALIS is a gap between the superior part of tragus
and root of helix, which is devoid of cartilage having only fibrous
tissue.
• Endaural approach-inscion made on this area will not cut through the
cartilage in surgery of EAC or Mastoid.

8. APPLIED ANATOMY
• Tragal cartilage, perichondrium from tragus, concha, fat from lobule is
used in reconstruction surgery for middle ear
• Conchal cartilage – correct depressed nasal bridge,
• Composite graft of skin & cartilage from pinna – repair the defects of
nasal ala.

9. NERVE SUPPLY - PINNA
• Greater auricular nerve
Most of the medial surface
of pinna, posterior part of lateral
surface
• Lesser occipital
Upper part of medial surface
• Auriculo temporal
Tragus
Crus of helix
adjacent part of helix.

10. • Auricular branch of vagus
Concha
corresponding eminence on medial surface
• Facial nerve
distributed with fibers of auricular branch of vagus
Concha
Retroauricular groove

12. Blood & lymphatic supply of
pinna

13. EXTERNAL AUDITORY CANAL (EAC)
• Extends from bottom of concha to tympanic membrane
and is a bony cartilaginous canal.
• 24 mm (along post wall)
• Not a straight tube
• Outer part(cartilaginous) directed upwards, backwards & medially
• Inner part (bony) directed downwards, forwards & medially
• Pinna pulled upwards, backwards & laterally(make it straight)

14. EAC contd
• External auditory canal has 2 parts :-
• CARTILAGINOUS
• BONY

15. CARTILAGINOUS PART
• Outer 1/3rd & 8mm canal
• Continuation of cartilage which forms the frame work of pinna.

16. • Skin covering the cartilaginous canal is thick and contains
appendages like
• 1.CERUMINOUS GLANDS(modified sweat gland),which
secrets cerumen (wax)
• 2.PILOSEBACEOUS GLANDS
• 3. HAIR is only confined to the outer canal & therefore
furuncles are seen only in the outer 1/3rd of canal

17. • Two deficiencies
(fissures of
Santorini) :-
Infections from
parotid and superficial
mastoid can enter the
canal and vice-versa.

18. BONY PART
• Inner 2/3rd & 16mm
• Skin lining the bony canal in thin & continuous
over the tympanic membrane
• Devoid of skin appendages(Hair and
ceremonious Glands
• About 6mm lateral to tympanic membrane ,
bony meatus presents as narrowing called
ISTHMUS
• Foreign body lodged medial to isthmus, get
impacted & are difficulty to remove.
• Notch of Rivinus- junction of
tympanosquamous and tympanomastoid
suture lines.

19. • Anteroinferior part of deep meatus, beyond the isthmus, presents a
recess - Anterior recess which acts as a cesspool for discharge &
debris
• Antero inferior part of bony canal may present a deficiency in children
up to age of 4 or sometimes in adults permitting infection to & from
parotid (Foramen of Huschke)

20. NERVE SUPPLY - EAC
• Auriculo temporal nerve(V3)
Anterior wall & roof
• Auricular branch of vagus (X)
Posterior wall & floor
• Posterior wall of auditory canal also receives sensory fibres of CN VII
through auricular branch of vagus.

21. Blood supply of EAC
• Post auricular artery
• Superficial temporal

22. Lymphatic drainage
• Anterior wall :- Preauricular lymph nodes
• Posterior wall :- LN at mastoid tip
• Rest :- upper deep cervical lymph nodes

24. Tympanic membrane
• Cone shaped, Thin, oval disc shaped.
 55 degree angled.
 Longest diameter :- 9-10 mm (i.e. posterosuperior to
anterosuperior)
 Shortest diameter :- 8-9 mm (perp. To longest diameter)
 Width :- 0.1 mm

25. •  Umbo :- maximum depression seen at the
• inf. tip of handle of malleus.
•  Cone of light :-
• radiating from umbo into the anteroinferior
quadrant.

27. Layers of the TM
•  TM has 3 layers :-
 Epithelial (outer)- continuous with skin of EAC
 Fibrous/lamina propria(middle) – missing in upper part
• 3 types of fibres
• Radial
• Circular
• Parobolic
 Mucosal (inner) – continuous with middle ear mucosa

28. Parts of tympanic membrane
• PARS TENSA
• PARS FLACCIDA (SHRAPNEL’S MEMBRANE)

29. PARS TENSA
• Forms most of Tympanic Membrane
• Periphery is thickened to form a fibro cartilaginous ring – ANNULUS
TYMPANICUS, which fits in tympanic sulcus
• Central part of pars tensa is tented inwards at the level of tip of
malleus – UMBO
Bright Cone of Light – seen radiating from the tip of malleus to
periphery in anterioinferior quadrant

30. PARS FLACIDA
• Situated above lateral process of malleus between the notch of
rivinus & anterior & posterior malleolar fold
• Appear slightly Pinkish

31. Nerve supply of TM

32. Blood supply of TM

33. Lymphatic drainage of TM

34. Middle ear
• Tympanic cavity – six
sided cavity
• 1. Epitympanum - above
malleolar folds of TM
• 2.Mesotympanum- medial to
pars tensa of TM
• 3.Hypotympanum- below the level oft
TM.

35. •Six sided cavity
•  Roof – separated from MCF – tegmen tympani
•  Floor – separated from IJV – thin plate of bone
•  Anterior wall
•  Posterior wall
•  Medial wall
•  Lateral wall

37. Anterior wall
• Will separate ME from
ICA
•  Structures passing are
• 1. Canal for chorda tympani .N
• 2. Canal for tensor tympani .M
• 3. Eustachian tube
• 4. Ant malleolar ligament

38. Posterior wall
 Upper part – aditus which
leads to mastoid antrum
 Below aditus triangular
projection processus pyramidalis
 Facial recess – supra pyramidal recess
 Sinus tympani – infra pyramidal recess

39. Lateral wall
• Separate external ear from middle ear
• Formed by TM and
squamous part of temporal bone

40. Medial wall
•  Separate middle ear
from inner ear
•  Important structures are
• 1.Promontory
• 2.Bony lat SCC
• 3.Oval window – closed by
footplate of stapes
• 4.Round window – closed by secondary TM
• 5.Facial nerve

41. Contents of the middle ear
•  Ear ossicles
• 1. Malleus (hammer)
• 2. Incus (anvil)
• 3. Stapes (stirrup)
•  Muscles
• 1. Tensor tympani
• 2. Stapedius
•  Mucosal folds
•  Nerves
•  vessels

44. Muscles
• STAPEDIUS
• origin- pyramid,
• Insertion- into posterior part of neck &
upper part of posterior crus,
• Supplied by small br. of FN
• TENSOR TYMPANI
• Origin- walls of bony canal above ET,
cart.part of ET, greater wing of sphenoid
• Insertion- medial aspect of
upper end of handle of malleus
• supplied by branch of mandibular nerve

45. Nerves & vesselsof middle ear
•  Chorda tympani nerve
•  Tympanic plexus
•  Plexus of vessels of stylomastoid artery
•  Carotico tympanic artery

46. Mastoid
•  3 important parts
• 1. Aditus – connects
epitympanum with mastoid
• 2. Antrum – largest air
cell in the mastoid bone
• 3. Mastoid air cells

47. Mac Ewen’s
triangle
• Bounded by temporal line
of supra mastoid crest
• and postero superior bony
meatal wall and tangential
line joining these two

48. Blood supply
•  Middle meningeal artery
•  Maxillary artery
•  Asc pharyngeal artery
•  Posterior auricular artery

49. Nerve supply & lymphatics
• Sensory – tympanic br of 9th CN – Jacobson’s
nerve
•  Motor - tensor tympani muscle is supplied by
mandidular nerve and stapedius muscle is
supplied by facial nerve
•  Lymphatics – preauricular and
• retropharyngeal lymph nodes

50. INNER EAR

53. • The inner(internal) ear is
called as labyrinth, from the
complexity of its shape.
• It consists of two parts:
• 1.The bony labyrinth:
A series of cavities within the
petrous part of the temporal bone.
• 2.The membranous labyrinth:
A series of communicating
membranous sacs and ducts,
contained within the bony cavities.

54. Bony(osseous) labyrinth
• The bony labyrinth consists of 3 parts:
• 1. Cochlea: anteriorly
• 2. Vestibule: middle
• 3. Semicircular canals: posteriorly

55. The Vestibule
• It is central part of the bony labyrinth, and is situated
medial to the tympanic cavity, behind the cochlea,
and in front of the semicircular canals.
• In its lateral or tympanic wall is the fenestra vestibuli, closed by
the base of the stapes and annular ligament.

57. • Two recesses:
• 1. Spherical recess: lodges Saccule
• 2. Elliptical recess: lodges Utricle
• Below elliptical recess is the opening of aqueduct of vestibule
through which passes the endolymphatic duct..

59. • Fenestra vestibuli.
• b) Fenestra cochleae.
• c) Openings (5) of the semicircular canals
• d) Aqueductus vestibuli

60. Semicircular canals(SCC)
• 3 in numbers:
• Lateral(horizontal)
• Posterior
• Superior
• Lies at right angles to each other
• Each canal has an ampullated end and nonampullated
end
• Non-ampullated ends of PSCC and SSCC unite to
form a common channel Crus commune
• 3 SCC have 5 openings into Vestibule

61. Cochlea
A spiral shaped fluid
filled structure
Coiled tube making
2.5 to 2.75 turns
around a central
pyramid of bone=
Modiolus

62. • It forms a cone approximately 9 millimetres
(0.35 inch) in diameter at its base and 5
millimetres in height.
•  When stretched out, the tube is
approximately 30 millimetres in length; it is
widest—2 millimetres—at the point where the
basal coil opens into the vestibule and tapers
until it ends blindly at the apex.

64. Organ of corti through which electircal impulse(sound)
are sent along the auditory(cochlear) nerve to the brain

65.  Organ of Corti also called as “End organ of hearing”.
 It is found only in mammals and provided with hair
cells or auditory sensory cells.
 It evolved from the basilar papilla found in all
tetrapods
 It is highly specialized structures that respond to
fluid-borne vibrations in the cochlea with a shearing
vector in the hairs of some cochlear hair cells.
 It contains between 15,000-20,000 auditory nerve
receptors.