Contents of middle ear
Walls of middle ear
The mastoid and its air cell
Developement of mastoid
Blood supply of middle ear
MIDDLE EAR :
• The middle ear together with the eustachian tube,
aditus antrum and mastoid air cells is called middle
ear cleft it is lined by mucous membrane and filled
The middle ear communicates:
Anteriorly with nasopharynx through pharyngotympanic
Posteriorly with mastoid antrum and mastoid air cells
through aditus to antrum called aditus ad
The Eustachian tube, tympanic cavity, Attic,
Mastoid air cells develop from the Endoderm of
Tubotympanic recess which arises from the
First Pharyngeal Pouches.
Malleus and Incus are derived from Mesoderm of the First
Arch while the Stapes develop from the Second Arch except
its footplate and annular ligament which are derived from the
• Three small bones called ear ossicles: malleus, incus,
• Two muscles: tensor tympani and stapedius.
• Two nerves: chorda tympani and tympanic plexus.
• Vessels supplying and draining the middle ear.
• Ligaments of the ear ossicles.
• IT LIES ON PROMONTORY WHICH IS FORMED BY
• 1.TYMPANIC BRANCH OF GLOSSOPHARNGEAL
• 2. SYMPATHETIC FIBRES FROM THE PLEXUS
ROUND THE ICA
• IT CARRIES SECRETOMOTOR FIBRES FOR THE
PAROTID GLAND AND IT HAS CLINICAL
CORRELATION :FREYS SYNDROME
CHODRA TYMPANI NERVE
• BRANCH OF FACIAL NERVE
• ENTER INTO MIDDLE EAR THROUGH POSTERIOR
• IT CARRIES TASTE SENSE FROM 2/3 OF TONGUE
• IT SUPPLIES SECRETOMOTOR FIBRES TO
SUBMAXILLARY AND SUBLINGUAL GLANDS
• The posterior wall lies close to the
mastoid air cells.
• It presents a bony projection called
pyramid which gives orgin to
• Facial nerve runs in facial canal.
• Chorda tympani a branch of facial
nerve, leaves emerges from facial
canal through posterior canaliculus.
OVAL WINDOW IS CLOSED BY FOOTPLATE OF STAPES
ROUND WINDOW IS CLOSED BY SECONDARY TYMPANIC MEMBRANE
CANAL FOR FACIAL NERVE PRESENT ABOVE THE OVAL WINDOW
BONY LATERAL SEMICIRCULAR CANAL
LATERAL WALL :
FORMED LARGELY BY
FORMS WINDOW OF
It is a large air-containing space in the
upper part of the mastoid process.
It communicates anteriorly with tympanic
cavity through aditus ad antrum.
Its roof is formed by tegmen antri, which is
the backward continuation of tegmen
It separates the antrum from middle cranial
MASTOID AND ITS AIR SYSTEM:
Depending on developing of air cells Mastoid is of
1.Well-pneumatized or cellular.-Mastoid cells are well-
developed and intervening septa are thin.
2. Diploetic-Mastoid consists of marrow spaces and a
few air cells.
3. Sclerotic or acellular.-There are no cells or marrow
DEVELOPMENT OF MASTOID
• Mastoid develops from the squamous and petrous
• The petrosquamosal suture may persist as a bony
• The Korner’s septum, separating superficial
squamosal cells from the deep petrosal cells.
BLOOD SUPPLY OF
ANTERIOR TYMPANIC BRANCH OF MAXILLARY ARTERY – TYMPANIC MEMBRANE
STYLOMASTOID BRANCH OF POSTERIOR AURICULAR ARTERY –MIDDLE EAR AND MASTOID AIR CELLS
• 4 MINOR
PETROSAL BRANCH OF MMA
SUPERIOR TYMPANIC BRANCH OF MMA
BRANCH OF ARTERY OF PTEYGOID CANAL
TYMPANIC BRANCH OF ICA
• Mastoidits: infection of Mastoid process or the large
bone behind your ear . Middle ear infection cause most
cases of mastoiditis
• Facial nerve palsy: during surgical procedure which
involve middle ear accidental damage to facial nerve
may be caused which leads to facial muscles paralysis
and sometimes loss of taste.