Middle ear

Middle ear anatomy

1. PRESENTED BY:

GURJAR GANESH KUMAR

2. 6
CONTENT
•Features,Structures and Relationship
•Boundaries and it's content
•Bones
•Muscle
•Neuro-vascular
•Clinical significance
TOPIC
•Anatomy of the middle ear and it's clinical point

3. FEATURES AND STRUCTURES
•The middle ear is also
called the tympanic
cavity,or tympanum.
•It situated in the petrous
part of the temporal bone
between the external and
the internal ear.
•It's like a cube shaped.
•The distance separating
the medial and the lateral
wall are 6mm near the
roof, 2mm in centre, 4mm
near the floor.

4. RELATIONSHIP
•The middle ear communicates with:
ANTERIORLY - the nasopharynx through the auditory
tube
POSTERIORLY- the mastoid antrum and mastoid air
cells through the auditus to the mastoid antrum.
•The middle ear linked to the pistol. The trigger of
pistol is tympanic cavity, outlet is auditory tube,
handle is aditus to mastoid antrum and mastoid air
cells.

5. BOUNDARIES
Roof and Tegmental Wall
•The roof separates the middle ear from the medial
cranial fossa.
•It is formed by a thin plate of bone called tegmen
tympani.
•In young children, the roof presents a gap at the
unossified petrosquamous suture where the middle ear is
in direct contact with the meninges.
•In adults,the suture is ossified and transmits a vein from
the middle ear to the superior petrosal sinus.

6. Floor or Jugular Wall
•The floor is formed by the
plate, a part of temporal
bone.
•It seprate the middle ear
from the superior bulb of
internal jugular vein.
•It transmit the tympanic
branch of glossopharyngeal
nerve to medial wall of
middle ear through
tympanic caniculus.

7. Anterior or Carotid Wall
•Uppermost part - bears the opening of the canal
for the tensor tympani.
•Middle part - opening of the auditory tube.
•Inferior part - formed by thin plate of bone
which forms the posterior wall of the carotid
canal.

8. Posterior or Mastoid Wall
•Superiorly, there is an opening or aditus through
which the epitympanic recess communication
with the mastoid or tympanic antrum.
•A conical projection, called the pyramid. it has
an opening at its apex for passege of the tendon
of the stapedius muscle.
•Lateral to the pyramid and near to the posterior
canaliculus for the chorda tympani through
which nerve enter the middle ear cavity.

9. Lateral or membranous Wall
•The lateral wall separates the middle ear from the
external acoustic meatus. It is formed:
-Mainly by the tympanic membrane and the squamous
temporal bone
•Near the tympanic notch, there are two small
apertures.
1. The petrotympanic fissure
2. The anterior canaliculus for the chorda tympani nerve

10. Medial or Labyrinthine
The medial wall separate the middle ear from the
internal ear. It present the following features.
•The Promontory
•The Fenestra vestibuli
•The Fenestra cochlea
•The Prominence of the facial
•The Sinus tympani
•The Promienence of lateral semicircular canal.

11. CONTENT
Three small bone(the malleus,the incus and
the stapes).
•Ligaments of the ear ossicles.
•Two muscle,the tensor tympani and the stapedius.
•Vessels supplying and draining the middle ear.
•Nerves: chorda tympani and tympani plexus.
•Air.

12. •The bones of the middle ear are called the auditory
ossicles.They are malleus,incus and stapes. they are
connected in a chain-like manner,linking the tympani
membrane to the oval window of the internal ear.
EAR OSSICLES
1)Malleus
-It is the largest and most lateral of the ear bones.
attaching to the tympanic membrane via the handle of
malleus.
-The head of malleus lies in the epitympanic
recess,where it articulates with the next auditory
ossicle, the incus.

14. 2)Incus
•It is consist of a body and two limbs.
•The body articulates with the malleus.
•The short limb attaches to the posterior wall of the middle
ear and the long limb joins the last of the ossicles; the
stapes
3) Stapes
•Is the smallest bone in the human body.
•It joins the incus to the oval window of the inner ear.
•It is the stirrup-shaped,with a head,two limbs,and a base.
•The head articules with the incus,and the base joins the
oval window

15. JOINTS OF THE OSSICLE
1.The incudomalleolar joints is a saddle joint.
2.The incudostapedial joint is a ball and socket
joint. Both of them are synovial joints.
- They are surrounded by capsular ligaments.
Accessory ligaments are three for the malleus,
and one each for the incus and the stapes which
stabilize the ossicles.
- All ligaments are extremely elastic.

16. MUSCLES
•There are two muscles which serve a protective
function in the middle ear; the tensor tympani and
stapedius.
• They contract in response to loud noise, inhibiting
the vibrations of the malleus, incus and stapes, and
reducing the transmission of sound to the inner ear.
•This action is known as the acoustic reflex.

17. •Origin- Auditory tube
•Insertion- Handle of the
malleus
•Artery- Superior
tympanic artery
•Nerve supply- Medial
pterygoid from the
mandibular nerve(V3)
•Action- Tensing the
tympanic membrane
1)Tensor tympani

18. •Origin- Walls of
pyramidal eminence
•Insertion- Neck of the
stapes
•Artery- Stapedial branch
of posterior auricular
artery
•Nerve supply- Facial
Nerve (nerve to the
stapedius)
•Action-Control the
amplitude of sound
waves to the inner ear
2)Stapedius

19. ARTERIAL SUPPLY
The main arteries of the middle ear are as
follows.
1.The anterior tympanic branch of the maxillary
artery.
2.The posterior tympanic branch of the
stylomastoid branch of the posterior auricular
artery.
3.Petrosal and superior tympanic branches of middle
meningeal artery.
4.Branches of ascending pharyngeal artery.
5.Tympanic branches of internal carotid artery.

20. VENOUS DRAINAGE
•Veins from the middle ear drain into the superior
petrosal sinus and the pterygoid plexus of the
veins.
LYMPHATIC DRAINAGE
•Lymphatics pass to the preauricular and
retropharyngeal lymph nodes.

21. NERVE SUPPLY
1.The glossopharyngeal nerve.
2.The superior and inferior
caroticotympanic nerves

22. •

23. ❑ Fracture of the medial cranial fossa breaks the
roof of the middle ear, rupture the tympanic
membrane and thus cause bleeding through the
ear along with the discharge of CSF.


CLINICAL SIGNIFICANCE

24. ❑ Inflamation of the
auditory tube is often
secondary to an attack of
common cold.
➢ This cause pain in the ear
which is aggravated by
swallowing, due to
blockage of the tube Pain
is relieved by installation
of decongestant drops in
the nose which helps to
open the ostium.

25. ❑ Otosclerosis :- Sometimes bony fusion takes place
between the foot plate of the stapes and the
margins of the fenestra vestibuli.
▪This leads to defness.The condition may be
surgically corrected by putting a prosthesis

26. □Hyperacusis :- Due to paralysis stapedius
muscle, movement of stapes are dampened; so
sounds get distorted and get too high in volume.
This is called hyperacusis.

27. REFERENCE :
BD CHAURASIYA,
GRAY'S ANATOMY AND
SOURCES OF GOOGLE

28. THANK YOU