4. Auricle
• Eac- 1st branchial cleft
• 6th week of iul- Hillock of His- 6
tubercles coalasce to form the
pinna.
• Tragus- 1st arch tubercle
• Rest of the pinna – 5 tubercles of
2nd arch.
• 20 weeks – adult size
5. Pre auricular sinus/ cyst
Due to the faulty fusion of 1st and 2 nd arch-
between tragus & crus of helix.
6. EAC
• 1st cleft
• 16th week- cells in the bottom of cleft will
proliferate to form meatal plug- recanalization-
form the epithelial lining of bony meatus.
• Medial to lateral- deeper meatus is fully
developed while there is atresia in the outer
part.
• Fully formed in 28th week
10. Auricle / Pinna
• Single piece of fibro elastic cartilage except its
lobule
• 2 surfaces:
• Lateral- skin adherent to perichondrium
- different prominence & depression
different in every individual even in
identical twins
• Medial – skin is loose
- scaphoid , conchal, triangular
eminence
11. Lateral surface
• Helix- small prominence- Darwins
tubercle
• Anterior & parallel to helix- anti helix,
superiorly it divides into 2 crura which
encloses triangular fossa
Superiorly to 2 crura- scaphoid fossa
• Infront of antihelix- concha cavum-
divided into 2 parts by crus of helix
into cymba concha- mc evens triangle
• No cartilage between tragus & crus of
helix- incisura terminalis
12. AA
• Incisura terminalis- incision for endaural approach in the
surgery of EAC & mastoid
• Grafts- cartilage from tragus, perichondrium from tragus or
concha, fat from lobule- reconstructive surgery of middle ear
• Conchal cartilage –correct the depressed nasal bridge
• Skin and cartilage from pinna- defects of nasal ala
13. • Sebaceous cyst- common in medial surface
• Frost bite – outer surface of auricle, skin is
adherent. No subcut tissue.
• Perichondritis- cartilage is avascular, it
receives blood supply from perchondrium.
Stripping of perichondrium from cartilage –
haematoma- cartilage necrosis- cartilage
crumbled up- Boxers ear.
• Post aural/ wildes incision- 1 to 1.5 cm
below the retroaural groove
14. Ligaments Extrinsic ligaments
• Auricularis superior- scalp to spine of helix
• Auricularis anterior- scalp to triangular fossa-
temporal branch of facial nerve
• Auricularis posterior- scalp to cavum concha-
posterior auricular branch of facial nerve
Intrinsic ligaments
• Helicis major
• Helicis minor
• Tragicus
• Anti tragicus
Medial surface
• Transverse auricular muscle
• Oblique auricular muscle
15. Blood supply Branches of ECA
• Post. Auricular artery
• Ant. Auricular artery
• Small branch of occipital artery
16. Lymphatic drainage
• Upper part of lateral side- pre auricular nodes
• Medial – mastoid nodes
• Rest- upper deep cervical nodes
18. EAC
• From concha to tm
• 24mm long
• 2 parts ;
• Outer cartilage- 8mm, upwards ,backwards,
medially
• Inner bony- 16mm, narrow, downwards ,
forwards, medially.
• Pinna should be pulled upwards, backwards and
laterally
19. Cartilaginous canal
• 8mm
• 2 deficiencies- fissures of Santorini- infections and neoplasm spread from
mastoid, parotid to eac to and fro
• Skin contain glands & hairfollicles- furuncle
• Ceruminous glands- modified apocrine sweat glands- open into hairfollicle-
watery d/d – darkens and sticky
• Sebaceous glands- oily sebum
• Wax- cerumin, sebum, desquamated cells- antibacterial & anti fungal action
20. Bony canal
• 16mm long
• Tympanic bone of temporal bone
• Roof- squamous portion of temporal bone
• Skin is devoid of gland & hair follicle
AA
Isthmus- 6mm lateral to TM, lodges fb, difficult to remove
Anterior recess :Ant- inf of deep meatus- medial to isthmus-
Cesspool of discharge & debris in EE & ME infections
21. • Foramen of Huschke: deficiency in the ant-inf part of bony canal in children
uto 4 years, adults- infections to and fro from parotid
• Rosen’s incision- transcanal approach- 5 -7mm
lateral to annulus
• Epithelial migration- outward mass migration of
Skin of canal, towards the external opening-
0.05mm per day.
22. Blood supply
• Anterior & roof
superficial temporal A- branch of ECA
• Anterior & outer suface of TM:
Deep auricular A – branch of maxillary A
• Posterior surface of TM- posterior
auricular A
25. Tympanic membrane
• Oval shaped, medial end of
EAC, positioned obliquely, 55
degree with the floor of deep
bony canal
• 0.1 mm thick, 8-9 mm width,
9- 10 mm tall
• 2 parts : Pars tensa
• Pars flaccida
26. Pars tensa
• Its periphery thickened to form- a
fibrocartilaginous ring – annulus
tympanicus which fits in tympanic
sulcus, deficient superiorly- notch of
Rivinus.
• Central part of pars tensa, is tented
inwards at the level of tip of malleus-
umbo
• Cone of light- ant-inf quadrant
• Pars flaccida/
Shrapnell’s membrane
• Above lat. Process of malleus btw notch
of rivinus and ant. & post. Malleal fold
27.
28. Pars tensa
• Taut, safe disease
• Lateral to mesotympanum
• More collagen, less epithelium
• Mucosal surface- ciliated
• Tympanic sulcus
Pars flaccida
• Lax, unsafe disease
• Lateral to epitympanum
• Less collagen, more epithelium
• Mucosal surface- non ciliated
• Notch of rivinus
29. Nerve supply of TM
• Lateral surface- ant half- auriculotemporal nerve
• post half- auricular branch of vagus nerve,7th nerve
• Medial surface- tympanic branch of 9th nerve
30. AA
• Hitzelbergers sign- hypoesthesia of the post. Meatal wall. Acoustic
neuroma presses on facial nerve & sensory fibres are affected
• Vasovagal reflex/cough,bradycardia,cardiac arrest, syncope- due to
arnolds nerve while cleaning EAC
• Apetite- instill spirit can increase apetite due to vagus
• . Ramsay hunt syndrome- vesicles of HZ on post canal wall and
mastoid.
31. Blood supply
• External surface- deep auricular br. Of 1st part of maxillary artery
• Internal surface- anterior tympanic branch of maxillary artery
• stylomastoid branch of posterior auricular artery
• Venous drainage:
• External jugular vein
• Eustachian venous plexus
32. Anatomy of middle ear cleft
• Tympanic cavity
• Eustacian tube
• Mastoid air cells
33. Tympanic cavity
• Epitympanum/ attic:
lies above the malleolar fold, medial to shrapnells
membrane & bony attic wall
Mesotympanum:
opposite to pars tensa
hypotympanum;:
Lying below pars tensa.
protympanum:
Around the tympanic orifice of eustacian tube.
Retro tympanum:
Posteriorly, posteromedial and posterior wall of
tympanic cavity
34.
35.
36. Lateral wall/ membraneous wall
• Sup- epitympanic
• Centrally- tm
• Inf- hypotympanum
• scutum:
lateral epitympanic is wedge
shaped, its sharp inferior portion – outer
attic or scutum
• Thin & easily eroded by cholesteatoma-
tell tale sign in HRCT
37. • Anterior canaliculus/ canal of huguier:
medial end of petrotympanic fissure, CT exits
• Posterior canaliculus:
Post bony wall, just medial to tympanic sulcus
• Petrotympanic fissure:
Transmits ant. Malleolar lig
Ant. Tympanic branch of maxillary artery
38. Chorda tympani
• Branch of facial nerve enters the
tympanic cavity from posterior
canaliculus – medial surface of tm btw
mucosal & fibrosal- medial to upper
portion of handle of malleus above
tensor tympani – leave by anterior
canaliculus- joins petrotympanic suture
39. Roof/ tegmen wall
• Roof – tegmen tympani- sep ME from MCF
• Petrosquamous suture line – do not close until adult life- infection to
extradural space
• Cog- bony crest projects from tegmen tympani caudally to lie anterior
to head of malleus- residual cholesteatoma
40. Floor of ME
• Overlies the dome of jugular bulb
• Occasionally, floor is dehiscent, bulb is covered only by fibrous &
mucous membrane-
• Jn of medial & floor, inferior tympanic canaliculus- allows tympanic
branch of GP nerve into ME
41. Anterior wall/ carotid wall
• Separates from ICA
• 2 openings- upper one for TT
lower one- ET
• Carotid artery with
caroticotympanic nerves
42. Medial/ labyrnthine wall
• Promontory- bulge due to basal cochlea, tympanic
plexus
• Ow/ fenestra vestibuli-:
opens into vestibuli- 3.25mm x 1.75mm closed by FP
Sup- horizontal segment of FN( facial canal)- prone for
injuries
Ant- processus cochelariformis
Inf- promontory
Post- ponticulus
• RW:
Triangular in shape2.3mm to 1.9mm
Barotrauma/ head injury can rupture RW- SNHL
Opens into scala tympani
43. • Anterosup- promontory
• Post-sup- subiculum
• Inf- hypotympanum
• Deep to rw- scala tympani
• Fallopian canal- ant-sup to promontory & OW, then turn inferiorly in
posterior wall.
• PC- hook like projection anterior to OW
Tendon of TT take a lateral turn to get attached to neck of malleus
Marker of geniculate ganglion of FN- landmark for FN SX
44. Posterior wall/ mastoid wall
Pyramid- bony projection through which stapes tendon is attached to
neck of stapes
Aditus- attic communicates with andrum
Facial recess:
superior- fossa incudis
Medial- vertical part of facial nerve
Lat- chorda tympani
site of cholesteatoma
Facial recess aproach/ - approach to mastoid without disturbing TM in
case of cochlear implant, Facial nerve decompression.
45. • Sinus tympani- largest
med to pyramid
Sup – ponticulus
Inf – subiculum
Suplat – pyramid
Lat – facial nerve
