Middle ear Anatomy

Middle ear Anatomy

Q. 1

Which of the following inhalation anaesthetics should be avoided in middle ear surgery when tympanic grafts are used:

 A Halothane
 B Nitrous oxide
 C Ether
 D Isoflurane
Q. 1

Which of the following inhalation anaesthetics should be avoided in middle ear surgery when tympanic grafts are used:

 A Halothane
 B Nitrous oxide
 C Ether
 D Isoflurane
Ans. B

Explanation:

Nitrous oxide


Q. 2

Which of the following inhalation anaesthetics should be avoided in middle ear surgery

 A

Halothane

 B Nitrous oxide
 C Ether
 D Isoflurane
Q. 2

Which of the following inhalation anaesthetics should be avoided in middle ear surgery

 A

Halothane

 B Nitrous oxide
 C Ether
 D Isoflurane
Ans. B

Explanation:

Nitrous oxide


Q. 3

Referred pain from tonsil to middle ear is due to:

 A

Glossopharyngeal nerve

 B

Greater auricular nerve

 C

Auriculotemporal nerve

 D

Chorda tympani nerve

Q. 3

Referred pain from tonsil to middle ear is due to:

 A

Glossopharyngeal nerve

 B

Greater auricular nerve

 C

Auriculotemporal nerve

 D

Chorda tympani nerve

Ans. A

Explanation:

Q. 4

Which of the following sequence is TRUE about structures affected in blast injuries?

 A

Liver> bowel> lung>middle ear

 B

Bowel>liver>middle ear> lung

 C

Liver < bowel < lung < middle ear

 D

Middle ear> bowel> lung> liver

Q. 4

Which of the following sequence is TRUE about structures affected in blast injuries?

 A

Liver> bowel> lung>middle ear

 B

Bowel>liver>middle ear> lung

 C

Liver < bowel < lung < middle ear

 D

Middle ear> bowel> lung> liver

Ans. C

Explanation:

“The structure injured by the primary blast wave, in order of prevalence, are the middle ear, the lung, and the bowel”

  • The hollow organ containing gas or air are most readily damaged by blast waves. The homogeneous tissues like liver and muscles are least likely injured.
  • In the underwater blast, injuries occur mostly in gastrointestinal tract and less commonly in lungs.
  • The lung injuries can introduce air into the circulatory system. Death may occur from systemic air embolism.
  • Tympanic membrane rupture is a sensitive marker for primary blast injuries.

Ref: Love & Bailey 24/e, p 298-300; Reddy 29e, p 216; Parikh, 6/e, p 4.183-4.184


Q. 5

All of the following are TRUE about the middle ear, EXCEPT:

 A

The joints between ossicles are synovial

 B

The chorda tympani nerve is related to the lateral wall

 C

The facial nerve passes in a canal situated in the medial and anterior walls

 D

The auditory tube connects the nasopharynx with the anterior wall

Q. 5

All of the following are TRUE about the middle ear, EXCEPT:

 A

The joints between ossicles are synovial

 B

The chorda tympani nerve is related to the lateral wall

 C

The facial nerve passes in a canal situated in the medial and anterior walls

 D

The auditory tube connects the nasopharynx with the anterior wall

Ans. C

Explanation:

The facial nerve passes in a canal situated in the posterior and medial walls of the middle ear. It is not associated with the anterior wall. 

 


Q. 6

Teunissen’s classification is used in classification of congenital anomalies of:

 A

Middle ear

 B

Larynx

 C

Trachea

 D

Pharynx

Q. 6

Teunissen’s classification is used in classification of congenital anomalies of:

 A

Middle ear

 B

Larynx

 C

Trachea

 D

Pharynx

Ans. A

Explanation:

Historically, congenital malformations of the ear have been divided into major and minor types with the latter limited to the middle ear alone.

Teunissen’s classification system is based on the site of involvement and aids in determining the appropriateness for surgery.


Q. 7

During development, the parts of ear develops at different intervals. All of the following are of adult size at birth, EXCEPT ?   

 A

Oval window

 B

Ear Ossicles

 C

Middle ear cavity

 D

Maxillary antrum

Q. 7

During development, the parts of ear develops at different intervals. All of the following are of adult size at birth, EXCEPT ?   

 A

Oval window

 B

Ear Ossicles

 C

Middle ear cavity

 D

Maxillary antrum

Ans. D

Explanation:

Maxillary antrum reaches adult size by 15 yrs of age. 

At birth all three ossicles are of adult size and shape. Malleus and incus grow to adult size by 15 weeks and stapes by 18 weeks. The middle ear cavity is approximately adult sized at birth, as are the oval window, round window.
Ref: Pediatric Otolaryngology, Volume 1, By Cuneyt M. Alper, Ellis M. Arjmand, Sylvan E. Stool, Margaretha L. Casselbrant, 2003, Page 134.

Q. 8

Tympanic plexus present in –

 A

Tunica adventitia of internal jugular vein

 B

Medial projection of middle ear cavity

 C

Part of tympanic membrane

 D

All

Q. 8

Tympanic plexus present in –

 A

Tunica adventitia of internal jugular vein

 B

Medial projection of middle ear cavity

 C

Part of tympanic membrane

 D

All

Ans. B

Explanation:

B i.e. Medial projection of middle ear cavity 

Tympanic nerve arises from the glossopharyngeal nerve, just below the jugular foramen. It passes through the floor of middle ear and reaches onto the mucous membrane covering the promontory(2, where it splits into branches and joint branches of internal carotid plexus to form tympanic plexus.

Promontary is round bulging in the medial or labyrinthine wall of middle ear cavityQ produced by the first turn of cholea.


Q. 9

The conclusion post mortem finding of death by drowning :

 A

Cutis anserine

 B

Presence of water in the middle ear

 C

Edematous lungs

 D

All

Q. 9

The conclusion post mortem finding of death by drowning :

 A

Cutis anserine

 B

Presence of water in the middle ear

 C

Edematous lungs

 D

All

Ans. B

Explanation:

B i.e. Presence of water in the middle ear


Q. 10

The distance between tympanic membrane and medial wall of middle ear at the level of center is:

 A

3 mm

 B

4 mm

 C

6mm

 D

2 mm

Q. 10

The distance between tympanic membrane and medial wall of middle ear at the level of center is:

 A

3 mm

 B

4 mm

 C

6mm

 D

2 mm

Ans. D

Explanation:

Q. 11

Narrowest part of middle ear is:

 A

Hypotympanum

 B

Epitympanum

 C

Attic

 D

Mesotympanum

Q. 11

Narrowest part of middle ear is:

 A

Hypotympanum

 B

Epitympanum

 C

Attic

 D

Mesotympanum

Ans. D

Explanation:

 

When seen in corona section, the cavity of the middle ear is biconcave, as the medial and lateral walls are closest to each other in the center.


Q. 12

Sensory nerve supply of middle ear cavity is provided by:

 A

Facial

 B

Glossopharyngeal

 C

Vagus

 D

Trigeminal

Q. 12

Sensory nerve supply of middle ear cavity is provided by:

 A

Facial

 B

Glossopharyngeal

 C

Vagus

 D

Trigeminal

Ans. B

Explanation:

 

  • The nerve supply of middle ear is derived from tympanic plexus which lies over the promontory.
  • The inferior ganglion of the glossopharyngeal nerve gives off the tympanic nerve which enters the middle ear through the tympanic canaliculus and takes part in formation of the tympanic plexus on the medial wall of middle ear.
  • This distributes it fibres to the middle ear, and also to the auditory tube, aditus ad atrum mastoideum (aditus to mastoid antrum).
  • Glossopharyngeal nerve —> Tympanic nerve/tympanic plexus —> Auditory tube

Q. 13

Tegmen seperates middle ear from the middle cranial fossa containing temporal lobe of brain by: 

 A

Medial wall of middle ear

 B

Lateral wall of middle ear

 C

Roof of middle ear

 D

Anterior wall of middle ear

Q. 13

Tegmen seperates middle ear from the middle cranial fossa containing temporal lobe of brain by: 

 A

Medial wall of middle ear

 B

Lateral wall of middle ear

 C

Roof of middle ear

 D

Anterior wall of middle ear

Ans. C

Explanation:

Q. 14

All are true about facial recess except:

 A

Supra pyramical recess

 B

Medially it is bounded by chorda tympani and laterally by facial nerve

 C

Important in cochlear implant

 D

Middle ear can be approached through it

Q. 14

All are true about facial recess except:

 A

Supra pyramical recess

 B

Medially it is bounded by chorda tympani and laterally by facial nerve

 C

Important in cochlear implant

 D

Middle ear can be approached through it

Ans. B

Explanation:

 



Q. 15

Floor of middle ear cavity is in relation with:

 A

Internal carotid artery

 B

Bulb of the internal jugular vein

 C

Sigmoid sinus

 D

Round window

Q. 15

Floor of middle ear cavity is in relation with:

 A

Internal carotid artery

 B

Bulb of the internal jugular vein

 C

Sigmoid sinus

 D

Round window

Ans. B

Explanation:

 

  • Internal carotid A is related to anterior wall of middle ear.
  • Round window is seen on the medial wall of middle ear.
  • Sigmoid sinus is not related to middle ear (directly, it lies posterior to mastoid).



Q. 16

Promontory seen in the middle ear is:

 A

Jugular bulge

 B

Basal turn of cochlea

 C

Semicircular canal

 D

Head of incus

Q. 16

Promontory seen in the middle ear is:

 A

Jugular bulge

 B

Basal turn of cochlea

 C

Semicircular canal

 D

Head of incus

Ans. B

Explanation:

Q. 17

Eustachian tube opens into middle ear cavity at:

 A

Anterior wall

 B

Medial wall

 C

Lateral wall

 D

Posterior wall

Q. 17

Eustachian tube opens into middle ear cavity at:

 A

Anterior wall

 B

Medial wall

 C

Lateral wall

 D

Posterior wall

Ans. A

Explanation:

 

The tympanic end of the eustachian tube is bony and is situated in the anterior wall of middle ear.

The pharyngeal end of the tube is slit like and is situated in the lateral wall of the nasopharynx, 1-1.25 cm behind the posterior end of inferior tubinate.



Q. 18

Lateral wall of middle ear is formed by:

 A

Tegmen tympani

 B

Mastoid process

 C

Promontory

 D

Tympanic membrane

Q. 18

Lateral wall of middle ear is formed by:

 A

Tegmen tympani

 B

Mastoid process

 C

Promontory

 D

Tympanic membrane

Ans. D

Explanation:

 

  • Roof – Thin plate called as tegmen tympani
  • Floor – Jugular bulb
  • Anterior wall – Internal carotid artery
  • Posterior wall – Lies close to mastoid air cells
  • Medial wall – labyrinth
  • Lateral wall – tympanic membrane



Q. 19

Bones of middle ear are responsible for which of the following?

 A

Amplification of sound intensity

 B

Reduction of sound intensity

 C

Protecting the inner ear

 D

Reduction of impedance to sound transmission

Q. 19

Bones of middle ear are responsible for which of the following?

 A

Amplification of sound intensity

 B

Reduction of sound intensity

 C

Protecting the inner ear

 D

Reduction of impedance to sound transmission

Ans. D

Explanation:

 

Broadly hearing mechanism can be divided into:

  • Mechanical conduction of sound (done by middle ear).
  • Transduction of mechanical energy into electrical impulses (done by sensory system of cochlea)
  • Conduction of electrical impulse to brain (i.e. auditory pathway)

i. Conduction of sound:

  • It is done mainly by middle ear. Middle ear not just simply conducts the sound but converts sound of great amplitude and less force to that of less amplitude and greater force.
  • This function of the middle ear is called as impedance matching mechanism or the transformer action.

ii. Transduction of mechanical energy to electrical impulse:

  • Movements of the stapes footplate causes vibrations in scala vestibuli followed by scala tympani and is transmitted to the cochlear fluids which brings about movement of the basilar membrane.
  • This sets up shearing force between the tectorial membrane and the hair cells.
  • The distortion of hair cells gives rise to electrical nerve impulse.

 

A sound wave, depending on its frequency, reaches maximum amplitude on a particular place on the basilar membrane, and stimulates that segment (traveling wave theory of von Bekesy).

Higher frequencies are represented in the basal turn of cochlea and the progressively lower one toward the apex.


Q. 20

Most common bony tumour of middle ear is:

 A

Adenocarcinoma

 B

Squamous cell carcinoma

 C

Glomus tumor

 D

Acoustic neuroma

Q. 20

Most common bony tumour of middle ear is:

 A

Adenocarcinoma

 B

Squamous cell carcinoma

 C

Glomus tumor

 D

Acoustic neuroma

Ans. B

Explanation:

Q. 21

Treatment of middle ear malignancy includes:

 A

Excision of petrous part of temporal bone

 B

Subcortical excision

 C

Modified radical mastoidectomy

 D

a and c

Q. 21

Treatment of middle ear malignancy includes:

 A

Excision of petrous part of temporal bone

 B

Subcortical excision

 C

Modified radical mastoidectomy

 D

a and c

Ans. D

Explanation:

 

Most common malignant tumor of middle ear and mastoid is squamous cell carcinoma.

Clinical Features

  • It affects age group 40-60 years
  • Slightly more common in females
  • Most important predisposing cause is long standing CSOM
  • Patient may present with chronic foul smelling blood stained discharge
  • Pain is severe and comes at night.
  • Facial palsy may be seen
  • 0/E – Friable, hemorrhagic granulation or polyp are present.
  • Diagnosis – made only on biopsy CT and angiography are done to see the extent of disease.

Metastasis occurs to cervical lymph nodes later.

Treatment of carcinoma of middle ear is combination of surgery followed by radiotherapy.

Surgery consists of radical mastoidectomy / subtotal or total petrosectomy depending on the extent of tumor.



Q. 22

Tendon of which muscle passes through the pyramid in middle ear

 A

Incus

 B

Stapedius

 C

Malleus

 D

Tensor veli palatine

Q. 22

Tendon of which muscle passes through the pyramid in middle ear

 A

Incus

 B

Stapedius

 C

Malleus

 D

Tensor veli palatine

Ans. B

Explanation:

A conical projection called the pyramid lies near the junction of the posterior and medial walls of the middle ear. It has an opening at its apex for the passage of the tendon of the stapedius muscle


Q. 23

Function of ossicles in middle ear is to _______

 A

Amplify intensity of sound

 B

Protect from loud sound

 C

Conduct sound energy from the tympanic membrane to the oval window and then to the inner ear fluid

 D

None of the above

Q. 23

Function of ossicles in middle ear is to _______

 A

Amplify intensity of sound

 B

Protect from loud sound

 C

Conduct sound energy from the tympanic membrane to the oval window and then to the inner ear fluid

 D

None of the above

Ans. C

Explanation:

 

The ossicles (auditory ossicles) are the three smallest bones in the body, the malleus, the incus, and the stapes.

They are contained within the middle ear space and serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea).


Q. 24

Scutum is present in middle ear ‑

 A

Roof

 B

Lateral wall

 C

Medial wall

 D

Floor

Q. 24

Scutum is present in middle ear ‑

 A

Roof

 B

Lateral wall

 C

Medial wall

 D

Floor

Ans. B

Explanation:

 Lateral wall


Q. 25

Treatment of middle ear papilloma is ‑

 A

Myringotomy and simple excision

 B

Myringectomy and simple excision

 C

Tympanomastoidectomy

 D

Local infiltration with podophyllin

Q. 25

Treatment of middle ear papilloma is ‑

 A

Myringotomy and simple excision

 B

Myringectomy and simple excision

 C

Tympanomastoidectomy

 D

Local infiltration with podophyllin

Ans. C

Explanation:

Ans. is ‘c’ i.e., Tympanomastoidectomy

Middle ear pappilomas

The middle ear papillomas are rare presentations and medical literature is mainly limited to case reports or case series.

These include aggressive pappilary tumors, schneiderian type of pappilomas and inverted pappilomas.

They are associated with hearing difficulty and vertigo and may be associated with Von Hippel Lindau syndrome.

They tend to be slowly growing, locally aggressive non metastasizing neoplasms

The approach for treatment of such pathology is usually radical and tympanomastoidectomy is considered the treatment of choice. This gives the best chance of cure.


Q. 26

Which of the following is not a derivative of the middle ear cleft ‑

 A

Semicircular canal

 B

Mastoid air cell

 C

Tympanic cavity

 D

Eustachian tube

Q. 26

Which of the following is not a derivative of the middle ear cleft ‑

 A

Semicircular canal

 B

Mastoid air cell

 C

Tympanic cavity

 D

Eustachian tube

Ans. A

Explanation:

Ans. is ‘a’ i.e., Semicircular canal

The middle – ear cleft in the temporal bone includes :‑

  1. Eustachian tube
  2. The middle ear (tympanic cavity)
  3. Aditus which leads posteriorly to the mastoid antrum and air cells.


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