The document describes the anatomy and structures of the human ear. It is divided into three main parts: 1) The outer ear or external ear collects sound waves and directs them into the middle ear. 2) The middle ear contains the tympanic cavity with the ossicles (malleus, incus, stapes) that vibrate in response to sound and transmit the vibrations into the inner ear. It also contains muscles and nerves. 3) The inner ear or labyrinth contains the bony and membranous structures including the cochlea, vestibule and semicircular canals that sense sound and balance. The cochlea converts sound waves into neural signals that

2. EAR
 1st part ……………external ear
 2nd part….................middle ear
 3rd part……………..inner ear

3. EXTERNAL EAR

4. ANATOMY OF MIDDLE EAR CLEFT

5. THE MIDDLE EAR CLEFT
 The middle ear cleft consists of the
 tympanic cavity,
 Eustachian tube and
 mastoid air cell system.

6. THE TYMPANIC CAVITY
Divided into three
compartments
 Epitympanum
 Mesotympanum
 Hypotympanum

7. Walls of the
Tympanic Cavity
 It has 6 walls,
I. Membranous wall
(lateral wall)
II. Tegmental wall (roof)
III. Jugular wall (floor)
IV. Carotid wall (anterior
wall)
V. Labyrinthine wall
(medial wall)
VI. Mastoid wall
(posterior wall)

9. THE ROOF
 Tegment tympani

10.  It is formed by both the petrous and squamous portions of
the temporal bone
 The petrosquamous suture line, which does not close
until adult life, can provide a route of access for infection
into the extradural space in children
 Veins from the tympanic cavity running to the superior
petrosal sinus pass through this suture line

11. THE FLOOR
 The dome of the
jugular bulb
 Tympanic
branch of the
glossopharyngeal
nerve

12. THE ANTERIOR WALL
 Lower-third
carotid artery
 Middle-third
A)tympanic orifice of the
Eustachian tube
B)canal for the tensor
tympani muscle
 Upper-third
pneumatized

13. THE POSTERIOR WALL
 The aditus of
mastoid antrum
 Fossa incudis
 Pyramid
 Bony facial
canal(vertical part)

14. THE LATERAL WALL
Formed by the
 Bony lateral wall of
epitympanum
 Tympanic membrane
 Bony lateral wall of
hypotympanum

15. THE MEDIAL WALL
 The promontory
 Oval window
 Round window
 Oblique part of
facial canal

19. THE CONTENTS OF THE TYMPANIC CAVITY
The tympanic cavity contains the
 Ear ossicles – malleus, incus and stapes
 Muscles – Stapedius, Tensor tympani
 The chorda tympani and
 The tympanic plexus

20. EAR OSSICLES

21. THE MALLEUS (the hammer)
 Largest, 9 mm in length
 The head lies in the
epitympanum
 The head of the malleus
articulate with the body
of the incus by a synovial
joint
 The lateral process
prominent landmark on
the tympanic membrane
Body

22. THE INCUS (the anvil)
 Has a body and two processes
 The body lies in the epitympanum
 The short process lie in the fossa
incudes
 The long process descends into
the mesotympanum
 Lenticular process articulates with
the head of the stapes.

23. THE STAPES (the stirrup)
 Shaped like a stirrup
 Consists of a head, neck, the
anterior and posterior crura and a
footplate.
 The stapedius tendon inserts into
neck
 The two crura arise from lower part
of the neck
 Footplate lies in the oval window
where it is attached to the bony
margins by the annular ligament

24. THE STAPEDIUS MUSCLE
 Arises from wall of conical
cavity within pyramid
 Attaches to neck of stapes
 Helps to dampen loud sound,
 Preventing noise trauma
 Supplied by branch of Facial
Nerve

25. TENSOR TYMPANI MUSCLE
● Arises from
a)bony canal above ET
b)cartilagenous part of ET
c) greater wing of sphenoid
● Attaches to neck of malleus
● Tenses tympanic membrane
● Supplied by branch of
Mandibular Nerve

26. THE MASTOID AIR CELL SYSTEM

27.  The mastoid antrum air-filled sinus in the petrous part of
temporal bone.
 It communicates with the middle ear by the aditus.
 Antrum is well developed at birth.
 Volume = 2 ml (adult).
 The medial wall relates to the posterior semicircular canal.
 More deeply and inferiorly is the dura of the posterior cranial
fossa and the endolymphatic sac.
 The roof of the mastoid antrum and mastoid air cell space
form the floor of the middle cranial fossa.

28. MacEwen's triangle
– Temporal line
– Posterosuperior segment of bony EAC
– a tangent through the posterior border of EAC
 Normally lining of the mastoid is a flattened, nonciliated
epithelium without goblet cells or mucus glands.

29. THE BLOOD SUPPLY OF THE TYMPANIC CAVITY
 Arise from both the internal and external carotid system.
 The overlap is extensive and great variability is present.
 Anterior tympanic
 Stylomastoid
 Maxillary
 Posterior auricular
 Middle meningeal
 Ascending pharyngeal
 Artery of pterygoid canal and internal carotid arteries.
 The anterior tympanic and stylomastoid arteries are
the biggest.

30. Venous drainage
 Pterygoid plexus
 Superior petrosal sinus
Lymphatic
 Retropharyngeal
 Parotid lymph node

31. Applied anatomy
 Facial nerve injury
 Hyperacusis
 Eustachian catarrh
 Encephalitis

32.  Facial nerve injury
 Hyperacusis
 Eustachian catarrh
 Encephalitis
Applied anatomy

33. Otitis Media
 Otitis media is an infection
or inflammation of the
middle ear
 This inflammation often
begins when infections that
cause sore throats, colds, or
other respiratory or
breathing problems spread
to the middle ear

34. Otosclerosis
 Otosclerosis is the abnormal
growth of bone of the middle
ear. This bone prevents
structures within the ear from
working properly and causes
hearing loss
 Symptoms: Severe tinnitus,
recurring auditory memories,
and frequent vertigo

36.  The inner ear is called as
labyrinth, from the complexity
of its shape.
 It consists of two parts:
1. The osseous labyrinth
2. The membranous
labyrinth

37. The Osseous Labyrinth (labyrinthus osseous)
 Consists of three parts:
The vestibule,
semicircular canals
cochlea.
 lined by periosteum.
 Contain a clear fluid,
perilymph, in which the
membranous labyrinth is
situated

38. The Vestibule (vestibulum)
38

39. The Bony Semicircular Canals
 3 in number
superior, posterior, and lateral,
 Above and behind the vestibule.
 Unequal in length
 They open into the vestibule by five
orifices, one of the apertures being
common to two of the canals

40. THE COCHLEA
 Resemblance to a common snail-shell
 Anterior part of the labyrinth
 It is conical in form, and placed almost
horizontally in front of the vestibule
 Apex
 Base

41. Membranous labyrinth
consists of
 Cochlear duct,
 Two sacs, utricle and saccule
 Three semicircular ducts
 Endolymphatic duct & sac
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43. Blood supply of labyrinth
 Mainly by internal auditory a. (branch of AICA - branch of
basilar a.)
 Internal auditory artery divides into
1. Anterior vestibular artery
 Supplies utricle ,superior & lateral SCC
2. Common cochlear artery
 Main cochlear artery(80%)-supplies cochlea
 Vestibulocochlear artery
1. Post vestibular A.-supplies saccule & post SCC
2. Cochlear branch –supplies to cochlea4/15/2016 43

44. 4/15/2016 44

45. Venous drainage
 Mainly by:
 Internal auditory vein
 Vein of cochlear aqueduct
 Vein of vestibular aqueduct
These Drain into inferior
petrosal and sigmoid
sinuses.
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46. Conductive Hearing Loss

47. Sensorineural Hearing Loss

48. Labyrinthitis
Inflammation of the semi-circular canals give you a
sense of motion when you’re not moving = VERTIGO
(dizziness) or LABYRINTHITIS

49. Meniere’s Disease
 Vertigo, balance problems,
 Loss of low pitches
 Tinnitus
 Fluctuating hearing loss

50. THANK YOU