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The ear performs two major functions: hearing and maintenance of equilibrium. It is divided into three parts: external ear, middle ear, and internal ear.
The tympanic membrane separates the external and middle ear.
The external ear consists of:
Auricle (Pinna)
External Acoustic Meatus
Made of a single crumpled elastic cartilage plate, covered by skin on both sides.
The lobule contains no cartilage; made of fibrofatty tissue.
Helix, Antihelix, Concha, Tragus, Scaphoid fossa
The concha leads into the external acoustic meatus.
Intrinsic and extrinsic muscles are vestigial in humans; facial nerve supplies them.
Lateral surface upper 2/3 → Auriculotemporal nerve
Lateral surface lower 1/3 → Great auricular nerve
Medial surface upper 2/3 → Lesser occipital nerve
Medial surface lower 1/3 → Great auricular nerve
Root → Auricular branch of vagus nerve
Posterior auricular artery
Superficial temporal artery
To preauricular and postauricular lymph nodes.
Conducts sound waves from concha to tympanic membrane.
S-shaped, with three directional changes:
Outer: Medially, forwards, upwards
Middle: Medially, backwards, upwards
Inner: Medially, forwards, downwards
Length: 24 mm
Medial 2/3 (16 mm): Bony
Lateral 1/3 (8 mm): Cartilaginous
Narrowest point = isthmus, 5 mm from tympanic membrane.
Bony part: Thin skin adherent to periosteum
Cartilaginous part: Skin with hairs, sebaceous glands, ceruminous (wax) glands
Outer canal → Superficial temporal, Posterior auricular arteries
Inner canal → Deep auricular branch of maxillary artery
Drain to preauricular, postauricular, and superficial cervical nodes.
Anterior half → Auriculotemporal nerve
Posterior half → Auricular branch of vagus nerve
External meatus is exposed by cutting the tragus.
Anterior walls of the cartilaginous and bony meatus are removed carefully to avoid injuring the tympanic membrane.
Thin, translucent partition forming the lateral wall of middle ear.
Size: 9 × 10 mm, oval, placed obliquely at 55°.
Faces downwards, forwards, laterally.
Outer surface: Thin skin, concave
Inner surface: Attached to handle of malleus; convex; central point = umbo
Periphery thickened and attached to tympanic sulcus;
Upper sulcus absent → attachment at tympanic notch
Anterior and posterior malleolar folds extend from notch to lateral process of malleus
Wax accumulation → itching; consider fungal infection/foreign body
Foreign bodies (seeds, insects): removed by syringing
Herpes zoster oticus due to vagus–facial nerve connection
Perichondritis → infection of elastic cartilage
Haematoma between cartilage & perichondrium → cauliflower ear if fibrosed
Divided into:
Pars flaccida (upper small)
Pars tensa (larger lower)
Disease in pars flaccida risks chorda tympani injury
Cone of light seen in anteroinferior quadrant during otoscopy
Structures seen through membrane: Handle of malleus, long process of incus
Myringotomy (membrane incision) may be done to drain middle ear pus
Located within the petrous temporal bone, the middle ear is an air-filled cavity between the tympanic membrane and the internal ear.
It contains ossicles, muscles, chorda tympani nerve, tympanic plexus, and opens into the auditory tube.
(Details in the text begin from page 314 onward.)
According to the document:
The tympanic membrane forms the lateral wall.
After removing it, the ossicles—malleus, incus, stapes—are exposed.
The handle of malleus attaches to the membrane.
The long process of incus and head of stapes can be visualized when the posterior wall is cleared.
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The general steps for dissection include:
Remove anterior wall of meatus without damaging the tympanic membrane.
Open the epitympanic recess to expose malleus–incus joint.
Trace the chorda tympani between malleus and incus.
Locate the opening of the auditory tube on the anterior wall.
(Explained in sections following page 318)
Converts air vibrations at the tympanic membrane into mechanical vibrations through the ossicles.
Enhances sound conduction from air (external ear) to fluid (internal ear).
Achieved by:
Lever action of ossicles
Area difference between tympanic membrane and stapes footplate
Prevents sound loss.
Tensor tympani and stapedius contract reflexively in response to loud noise.
Reduces transmission of excessive vibrations to the internal ear.
Through the auditory tube, air pressure is equalized between middle ear and nasopharynx.
Middle ear maintains normal aeration through the auditory tube.
Text indicates:
The mastoid antrum lies in the petrous part of the temporal bone, deep to the suprameatal triangle (15 mm in adults).
It communicates with:
Middle ear cavity (epitympanic recess)
Mastoid air cells
The roof of antrum is formed by the tegmen tympani.
Steps derived from dissection instructions:
The suprameatal triangle is used as a landmark.
Drilling deep to this triangle leads to the mastoid antrum.
The cavity is opened to expose the aditus ad antrum (opening into the epitympanic recess).
Mastoid air cells are inspected and cleared.
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Wax impaction causes itching; foreign bodies are common, especially seeds and insects → removed by syringing.
Painful vesicles in ear due to involvement of the geniculate ganglion via connections between auricular branch of vagus and facial nerve.
Haematoma between auricular cartilage & perichondrium leads to fibrosis and deformity, common in wrestlers.
Infection here endangers chorda tympani, located just behind it.
Cone of light appears in anteroinferior quadrant of tympanic membrane.
Visible structures: handle of malleus & long process of incus.
Incision of tympanic membrane to drain middle ear pus (usually in posteroinferior quadrant).
Infection spreads from middle ear to mastoid antrum and air cells; may require mastoidectomy.
Because the facial canal runs in the medial wall of the middle ear, infections or surgery can damage the facial nerve.
Lies deep within the petrous temporal bone.
Converts mechanical vibrations (sound) and head movements into nerve impulses.
Consists of:
Bony labyrinth (perilymph-filled)
Membranous labyrinth (endolymph-filled)
Vestibule
Central part.
Communicates with semicircular canals posteriorly and cochlea anteriorly.
Contains oval window → receives stapes footplate.
Semicircular Canals (3 canals)
Anterior, Posterior, Lateral semicircular canals.
Each has an enlargement called ampulla.
Detect angular (rotational) acceleration.
Cochlea
Coiled like a snail (2¾ turns).
Contains scala vestibuli, scala tympani (both perilymph) and scala media (endolymph).
Spiral lamina divides cochlear canal.
Organ of Corti lies on basilar membrane → receptor of hearing.
Perilymph → between bony & membranous labyrinth
Endolymph → inside membranous labyrinth (K⁺ rich)
Utricle & Saccule
Located in vestibule.
Contain maculae → detect linear acceleration & gravity.
Semicircular Ducts
Correspond to semicircular canals.
Each ampulla contains crista ampullaris → detects rotational acceleration.
Cochlear Duct
Contains Organ of Corti with inner & outer hair cells.
Endolymph movement bends stereocilia → hearing transduction.
Macula (utricle & saccule) → linear acceleration
Crista ampullaris (semicircular canal ampulla) → rotation
Organ of Corti (cochlea) → sound
Cochlear nerve → hearing
Vestibular nerve → balance
Arises from hair cells → joins to form VIII nerve → passes through internal acoustic meatus → enters brainstem at pontomedullary junction.
Cochlear nuclei (ventral & dorsal)
Vestibular nuclei (superior, inferior, medial, lateral)
Injury causes:
Sensorineural hearing loss
Vertigo, nystagmus
Imbalance, nausea
Increased endolymph (endolymphatic hydrops).
Features: vertigo, tinnitus, hearing loss, fullness in ear.
Inflammation due to infection—causes severe vertigo and sensorineural loss.
Tumour of vestibular nerve in internal acoustic meatus.
Causes progressive unilateral SNHL, tinnitus, imbalance.
Drugs like aminoglycosides damage hair cells → irreversible SNHL.
Conflict between vestibular and visual inputs → nausea, sweating, dizziness.
Develops from otic placode → forms otic vesicle (otocyst).
Dorsal part → Utricle, Semicircular ducts
Ventral part → Saccule, Cochlear duct
Derived from otocyst.
Formed by surrounding mesenchyme → ossifies.
Developed from neural crest + otic placode neuroblasts.
FGF, Wnt, Shh (Sonic Hedgehog) regulate otic vesicle patterning.
Notch signaling determines hair cell vs supporting cell fate.
Atoh1 gene essential for hair cell differentiation.
Pax2, Pax8 guide cochlear development.
Mutations in hair-cell genes cause congenital deafness.
The document highlights multiple reasons:
Dry, hardened wax presses against the tympanic membrane.
Infection of hair follicles → severe localized pain.
Pain on pulling pinna; swollen canal.
Inflammation of tympanic membrane.
Middle ear infection → throbbing pain, fever, hearing loss.
Because the ear shares nerves with many structures:
Vagus nerve → throat, larynx disease causes earache
Glossopharyngeal nerve → tonsillitis, pharyngitis
Auriculotemporal nerve → TMJ pain
Trigeminal nerve (V3) → dental pain
Cervical nerves (C2–C3) → mastoid and neck pathology
Pain behind the ear; tenderness over mastoid.
During colds, sinusitis → pressure pain in the ear.
M → Malleus
I → Incus
S → Stapes
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1st arch: Malleus, Incus
2nd arch: Stapes
(Useful for development-related MCQs)
V → Auriculotemporal nerve (outer surface)
A → Auricular branch of vagus (outer surface)
go → Glossopharyngeal (inner surface)
(Combines all three nerves involved)
Perilymph → between bony and membranous labyrinth
Endolymph → inside membranous labyrinth
Macula (utricle & saccule): linear acceleration
Crista (semicircular canals): rotational acceleration
Develops from ectoderm, mesoderm, and endoderm.
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Outer surface: V (auriculotemporal) + X (auricular branch)
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Inner surface: Glossopharyngeal nerve
Syringing stimulates auricular branch of vagus → may slow heart rate.
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Endolymph is produced by stria vascularis; this process needs melanocytes.
Disorders like albinism may cause deafness.
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Tumour of Schwann cells of the vestibulocochlear nerve.
When it expands in the internal acoustic meatus → compresses VII, causing:
Facial paralysis
Hearing loss
Tinnitus
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Ear pain can originate from the ear, throat, nose, teeth, TMJ, or cervical nerves.
Detailed causes shown in the flowchart.
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Fusion of stapes footplate at the oval window → fixed ossicle chain.
Treated by stapedectomy + prosthesis.
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Infection from mastoid air cells may extend to:
Temporal lobe
Cerebellum
Sigmoid sinus
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Because it runs in the medial wall of the middle ear, near the mastoid antrum.
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Each canal is positioned 90° to the others.
Lateral canals of both sides lie in the same plane.
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The cochlea makes 2¾ turns around the modiolus.
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Oval window = fenestra vestibuli → opens into vestibule.
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Organ of Corti: hearing
Maculae: linear acceleration
Cristae: angular acceleration
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External acoustic meatus → 1st ectodermal cleft
Auricle → six mesenchymal hillocks from 1st & 2nd arches
Middle ear + auditory tube → tubotympanic recess
Malleus & incus → 1st arch
Stapes → 2nd arch
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WNT, BMP → formation of otic placode
Retinoic acid → AP differentiation of otic vesicle
SHH, WNT → semicircular canals + cochlear duct
PAX2, Noggin defects → congenital deafness
A clinicoanatomical case is described where a young boy has deformity of the auricle/pinna, but no treatment is given and he functions normally in school and games.
What are the uses of the auricle?
What is its nerve supply?
The pinna has minimal medical importance, but several practical and cosmetic uses:
Lobule is used for wearing earrings of various shapes and sizes.
Supports spectacles/glasses – its shape naturally accommodates them.
A small piece of auricular skin can be used to test for lepra bacilli.
Hairy pinna can be a marker associated with the Y-chromosome.
Culturally, the pinna was traditionally pulled as punishment for disobedience.
Medial surface (upper 2/3): Lesser occipital nerve
Medial surface (lower 1/3): Great auricular nerve
Lateral surface (upper 2/3): Auriculotemporal nerve
Lateral surface (lower 1/3): Great auricular nerve
The text includes a short poetic advisory highlighting the dangers of continuous loud sound exposure.
Noise pollution causes mind–body suffering.
One should plug ears, lower volume, and seek policing against excessive noise.
Gentle, soft speech induces calmness; loud prolonged noise damages auditory pathways.
Prolonged exposure may eventually cause auditory crippling.
One may even consider changing jobs if noise exposure is unavoidable, but hearing must be protected at all costs.
Excessive phone use at high volume may cause significant hearing loss.
Indoor noise (music albums, TV advertisements) can also damage:
Cochlear nerves
Temporal lobes
Can cause irritation, hypertension, obesity
A patient complains of ear pain whenever he swallows or yawns. Otoscopy is normal.
Pain is referred from the pharynx or auditory tube because both are supplied by the glossopharyngeal nerve (IX).
The glossopharyngeal nerve also supplies the inner surface of the tympanic membrane, so inflammation in the throat may present as otalgia.
Pulling the patient’s pinna or pressing the tragus causes severe pain.
Indicates otitis externa (infection of the external acoustic meatus).
The skin of the cartilaginous canal is tightly adherent and contains hair follicles and ceruminous glands → very painful when inflamed.
During syringing of the ear for wax removal, the patient suddenly develops dry cough and mild bradycardia.
Stimulation of the auricular branch of vagus nerve supplying outer surface of tympanic membrane produces:
Cough reflex
Vagal bradycardia
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A child with chronic otitis media develops facial asymmetry.
Infection in middle ear can spread to the facial canal, which lies in the medial wall of the tympanic cavity.
Inflammation compresses the facial nerve, causing lower motor neuron facial palsy.
Tenderness over the mastoid region, with protruding auricle.
Suggests mastoiditis due to spread of infection from middle ear to mastoid air cells.
Mastoid antrum lies 12–13 mm deep to the suprameatal triangle.
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Gradual hearing loss with normal tympanic membrane.
Suggestive of otosclerosis—fixation of stapes at the oval window.
Stapes is a derivative of the 2nd pharyngeal arch; its immobility prevents sound conduction.
A patient with recurrent middle ear infections complains of metallic taste and taste loss.
Disease in pars flaccida endangers the chorda tympani nerve, which carries taste from anterior 2/3 of tongue.
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A patient experiences spinning sensation when changing head position.
Involvement of semicircular canals or crista ampullaris—responsible for detecting rotational acceleration.
May represent benign positional vertigo or vestibular irritation.
History of prolonged headphone use.
Chronic noise exposure damages cochlear hair cells → gradual loss of perception of soft sounds.
The document notes: one may become “deaf to soft sounds on continuous exposure to loud sounds.”
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Patient presents with dull pain, blocked sensation, and reduced hearing.
Wax in cartilaginous canal presses on sensitive skin supplied by auriculotemporal nerve → pain.
May trap moisture and lead to fungal infection.
A patient with long-standing otitis media develops ataxia and vomiting.
Infection may spread from mastoid air cells to posterior cranial fossa, involving cerebellum, causing cerebellar abscess.
A patient with vertigo shows rhythmic involuntary eye movements.
Disturbance of vestibular nuclei or semicircular ducts → imbalance of vestibulo-ocular reflex → nystagmus.
History of fever and ear pain.
Acute otitis media causes pus accumulation behind tympanic membrane.
Treatment may require myringotomy in posteroinferior quadrant.
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Extreme discomfort, buzzing sensation.
Cartilaginous canal contains hair + ceruminous glands, and has vagal nerve supply, making foreign body presence extremely painful.
Removal by syringing is recommended.
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External ear is malformed.
External ear develops from six tubercles of 1st and 2nd branchial arches.
Deformities occur when these hillocks fail to fuse properly.
Answer:
The auricle is made of elastic cartilage, except for the lobule, which contains fibrofatty tissue and no cartilage.
Answer:
Outer surface:
Anteroinferior part → Auriculotemporal nerve (V3)
Posterosuperior part → Auricular branch of vagus (X), with a communicating branch from facial nerve
Inner surface:
Tympanic branch of glossopharyngeal nerve (IX)
Answer:
Ossicles: Malleus, Incus, Stapes
Joints:
Malleus–Incus → Saddle-type synovial joint
Incus–Stapes → Ball-and-socket type synovial joint
Answer:
Tensor tympani → Mandibular nerve (V3)
Stapedius → Facial nerve (VII)
Answer:
The tympanic membrane develops from all three germ layers:
Outer → Ectoderm
Middle → Mesoderm
Inner → Endoderm
Answer:
Stimulation of the auricular branch of the vagus nerve during syringing can trigger reflex nausea, cough, vomiting, or bradycardia.
Answer:
Roof: Tegmen tympani
Floor: Jugular wall
Anterior wall: Carotid wall
Posterior wall: Mastoid wall
Lateral wall: Tympanic membrane
Medial wall: Labyrinthine wall
Answer:
Aditus ad antrum
Pyramidal eminence
Fossa incudis
Answer:
Promontory (produced by cochlea)
Oval window
Round window
Prominence of facial canal
Answer:
Auditory (pharyngotympanic) tube
Canal for tensor tympani muscle
Answer:
Bony semicircular canals: 3
Membranous semicircular ducts: 3
Total: 6 structures
Answer:
Each duct has one ampulla, each containing one crista → 3 cristae.
Answer:
Macula is the sensory receptor in both utricle and saccule.
Answer:
The Organ of Corti on the basilar membrane is the receptor organ for hearing.
Answer:
They develop from the tubotympanic recess, derived from the endoderm of the 1st pharyngeal pouch.
Answer:
The membranous labyrinth develops from an ectodermal otic vesicle.
Answer:
A detailed flowchart lists causes, including:
Wax impaction
Otitis externa
Otitis media
Myringitis
Pharyngitis (referred pain via IX nerve)
Dental causes
TMJ problems
Cervical spine issues
Answer:
Located posterior to the external acoustic meatus.
Important surface landmark for mastoid antrum, located ~15 mm deep in adults.
Answer:
Mastoiditis
Facial nerve palsy
Labyrinthitis
Meningitis
Brain abscess (temporal lobe/cerebellum)
Sigmoid sinus thrombosis
(Complications inferred from multiple clinical anatomy sections showing spread of infection.)
Answer:
Pars tensa (lower tense part)
Pars flaccida (upper small slack part)
The auricle is made of elastic cartilage, except the lobule, which contains fibrofatty tissue only.
Outer surface: Auriculotemporal nerve (V3) + Auricular branch of vagus (X).
Inner surface: Glossopharyngeal nerve (IX).
Ossicles: Malleus, Incus, Stapes.
Joints:
Malleus–Incus: Saddle synovial joint.
Incus–Stapes: Ball-and-socket synovial joint.
Tensor tympani: Mandibular nerve (V3).
Stapedius: Facial nerve (VII).
It develops from ectoderm, mesoderm, and endoderm (all three germ layers).
Stimulation of the auricular branch of the vagus nerve can trigger a vagal reflex.
Roof – Tegmen tympani
Floor – Jugular wall
Lateral – Tympanic membrane
Medial – Labyrinthine wall
Anterior – Carotid wall
Posterior – Mastoid wall
Aditus to mastoid antrum, pyramidal eminence, fossa incudis.
Promontory, oval window, round window, prominence of facial canal.
The auditory tube and the canal for tensor tympani.
3 bony semicircular canals
3 membranous semicircular ducts
Three (one in each ampulla).
The macula.
The Organ of Corti.
Both develop from the 1st pharyngeal pouch, forming the tubotympanic recess.
From the ectodermal otic vesicle.
Wax, otitis externa, otitis media, myringitis, throat infections (referred via IX), dental pain, TMJ issues, cervical nerve irritation.
A bony landmark behind the external acoustic meatus; it overlies the mastoid antrum, located about 15 mm deep.
Mastoiditis, facial nerve palsy, labyrinthitis, meningitis, brain abscess, sigmoid sinus thrombosis.
Pars tensa
Pars flaccida
a. Hyaline
b. Elastic
c. Fibrocartilage
d. Costal cartilage
Answer: b. Elastic
a. Elastic cartilage
b. Hyaline cartilage
c. Fibrous tissue only
d. Bone
Answer: c. Fibrous tissue only
a. Outer cartilaginous part
b. Isthmus
c. Tympanic membrane
d. Junction of bony and cartilaginous canal
Answer: b. Isthmus
a. Glossopharyngeal
b. Facial
c. Auriculotemporal
d. Vagus
Answer: c. Auriculotemporal
a. Facial nerve
b. Glossopharyngeal nerve
c. Vagus nerve
d. Trigeminal nerve
Answer: b. Glossopharyngeal nerve
a. Trigeminal nerve
b. Facial nerve
c. Glossopharyngeal nerve
d. Vagus nerve
Answer: b. Facial nerve
a. Facial nerve
b. Vagus nerve
c. Mandibular nerve (V3)
d. Glossopharyngeal nerve
Answer: c. Mandibular nerve (V3)
a. Oropharynx
b. Nasopharynx
c. Laryngopharynx
d. Oral cavity
Answer: b. Nasopharynx
a. Malleus
b. Incus
c. Stapes
d. All three
Answer: c. Stapes
a. Scala vestibuli
b. Scala tympani
c. Scala media
d. Vestibule
Answer: c. Scala media
a. Hearing
b. Linear acceleration
c. Angular acceleration
d. Pressure changes
Answer: c. Angular acceleration
a. Rotational movement
b. Horizontal linear acceleration
c. Vertical linear acceleration only
d. No movement
Answer: b. Horizontal linear acceleration
a. Rotational acceleration
b. Horizontal acceleration
c. Vertical acceleration
d. Sound waves
Answer: c. Vertical acceleration
a. Crista
b. Macula
c. Organ of Corti
d. Spiral ganglion
Answer: c. Organ of Corti
a. Endoderm
b. Mesoderm
c. Neural crest
d. Ectodermal otic vesicle
Answer: d. Ectodermal otic vesicle
a. 1st pharyngeal cleft
b. 1st pharyngeal pouch
c. 2nd pharyngeal pouch
d. Otic placode
Answer: b. 1st pharyngeal pouch
a. Round window
b. Oval window
c. Tympanic membrane
d. Utricle
Answer: b. Oval window
a. Trochlear
b. Facial
c. Optic
d. Hypoglossal
Answer: b. Facial
a. Glossopharyngeal nerve
b. Greater petrosal nerve
c. Chorda tympani
d. Tympanic plexus
Answer: c. Chorda tympani
a. Cochlear duct
b. Vestibular apparatus
c. Tympanic membrane
d. Tensor tympani
Answer: b. Vestibular apparatus
a. Oval window
b. Round window
c. Aqueduct of cochlea
d. Reissner’s membrane
Answer: b. Round window
a. Tonsillitis
b. Otitis externa
c. Middle ear effusion
d. Glossopharyngeal neuralgia
Answer: d. Glossopharyngeal neuralgia
a. Otitis media
b. Otitis externa
c. Otosclerosis
d. Labyrinthitis
Answer: b. Otitis externa
a. Posterior superior
b. Anterior inferior
c. Posterior inferior
d. Anterior superior
Answer: b. Anterior inferior
a. Superior semicircular canal
b. Posterior semicircular canal
c. Lateral semicircular canal
d. Cochlear canal
Answer: c. Lateral semicircular canal
Elastic cartilage.
It has no cartilage—only fibrofatty tissue.
Lateral surface: Auriculotemporal nerve + Great auricular nerve
Medial surface: Great auricular nerve + Lesser occipital nerve
Concha: Auricular branch of vagus
The isthmus, about 5 mm lateral to the tympanic membrane.
The skin of the cartilaginous canal is tightly adherent and richly innervated.
Pearly grey, translucent, with a visible cone of light in the anteroinferior quadrant.
Pars tensa
Pars flaccida
The handle of the malleus.
Outer surface → Auriculotemporal nerve + Auricular branch of vagus
Inner surface → Glossopharyngeal nerve
Malleus, Incus, Stapes.
The stapes.
The stapes footplate.
Tensor tympani (V3)
Stapedius (VII)
Prevents excessive movement of stapes and protects the inner ear from loud sounds.
Loss of stapedius function → hyperacusis (sounds appear louder).
Equalises air pressure between the middle ear & nasopharynx.
Their auditory tube is short, wide and more horizontal.
Roof (tegmen), floor (jugular wall), anterior, posterior, lateral (membrane), medial (labyrinthine).
Promontory, oval window, round window, facial canal prominence.
Aditus to mastoid antrum, pyramidal eminence, fossa incudis.
About 15 mm deep to the suprameatal triangle.
Infection spreading from the middle ear to mastoid air cells.
The facial canal forms part of the medial wall of the middle ear.
The Organ of Corti.
Endolymph.
Perilymph.
Rotational (angular) acceleration.
Linear acceleration and gravity.
Maculae.
Crista ampullaris.
The central bony core of the cochlea.
The cochlear division of the vestibulocochlear nerve (VIII).
The vestibular division of VIII nerve.
Excess endolymph → vertigo, tinnitus, hearing loss.
Stapes fixation at the oval window, causing conductive deafness.
Age-related sensorineural hearing loss.
The skin of the auricle.
Shared nerve supply by the glossopharyngeal nerve.
Shared nerve supply via auriculotemporal nerve.
Stimulation of the auricular branch of vagus.
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