Contents of tympanic cavity/ middle ear

CONTENTS OF TYMPANIC CAVITY/ MIDDLE EAR

Q. 1

The stapes is a derivative of:

 A

1st arch

 B

2nd arch

 C

3rd arch

 D

4th arch 

Q. 1

The stapes is a derivative of:

 A

1st arch

 B

2nd arch

 C

3rd arch

 D

4th arch 

Ans. B

Explanation:

2nd arch


Q. 2

Which structure is attached to the center of the tympanic membrane?

 A

Footplate of the stapes

 B

Handle of the malleus

 C

Long process of the incus

 D

Tragus

Q. 2

Which structure is attached to the center of the tympanic membrane?

 A

Footplate of the stapes

 B

Handle of the malleus

 C

Long process of the incus

 D

Tragus

Ans. B

Explanation:

Q. 3

Stapes foot plate covers which of the following structure?

 A

Round window

 B

Oval window

 C

Inferior sinus tympanum

 D

Pyramid

Q. 3

Stapes foot plate covers which of the following structure?

 A

Round window

 B

Oval window

 C

Inferior sinus tympanum

 D

Pyramid

Ans. B

Explanation:

The stapes is the smallest bone in the human body and is located in the oval window.

Foot plate of the stapes rest on oval window, which is an opening of the vestibule and the scala vestibuli of the cochlea.

The oval window is located at the bottom of a deep depression outlined by the facial nerve superiorly, the promontory inferiorly, the cochleariform process anteriorly and the pyramidal eminence posteriorly. 
 

Q. 4

Which of the following contract together with stapes to stiffen the ossicular chain and protect the inner ear from noise damage?

 A

Scala media

 B

Tensor tympani

 C

Scala vestibuli

 D

Semicircular canal

Q. 4

Which of the following contract together with stapes to stiffen the ossicular chain and protect the inner ear from noise damage?

 A

Scala media

 B

Tensor tympani

 C

Scala vestibuli

 D

Semicircular canal

Ans. B

Explanation:

Stapedius and tensor tympani muscles contract through a neural reflex arc mediated by loud sounds (>80 dB).

They act to stiffen the ossicular chain and protect the inner ear from noise damage, particularly at low frequencies.

In contrast, cholesteatoma formation in the middle ear can contact the ossicular chain, increasing the total mass, causing a predominantly high-frequency conductive hearing loss.
 

Q. 5

The tensor tympani muscle is inserted to the handle of malleus. The nerve supply to tensor tympani is?

 A

Vagus nerve

 B

Glossopharyngeal nerve

 C

Trigeminal nerve

 D

Facial nerve

Q. 5

The tensor tympani muscle is inserted to the handle of malleus. The nerve supply to tensor tympani is?

 A

Vagus nerve

 B

Glossopharyngeal nerve

 C

Trigeminal nerve

 D

Facial nerve

Ans. C

Explanation:

The motor pure branches of mandibular division of trigeminal nerve:

  • Masseteric nerve (masseter muscle)
  • Deep temporal nerves (temporalis muscle)
  • Pterygoid nerves (pterygoid muscles)
  • Nerve of the tensor tympani muscle
  • Nerve to the tensor veli palatini muscle

Q. 6

The stapes is a derivative of which of the following pharyngeal arch?

 A

1st arch

 B

2nd arch

 C

3rd arch

 D

4th arch

Q. 6

The stapes is a derivative of which of the following pharyngeal arch?

 A

1st arch

 B

2nd arch

 C

3rd arch

 D

4th arch

Ans. B

Explanation:

Structures derived from second pharyngeal arch are stapes, styloid process of temporal bone, lesser cornu of hyoid bone and upper part of hyoid bone.

 
Skeletal and ligamentous elements derived from pharyngeal arches:
 

First arch

Malleus and incus
Portions of the mandible
Meckels cartilage
Sphenomandibular ligament
Anterior ligament of malleus

Second arch

stapes
Styloid process of temporal bone
Lesser cornu of hyoid bone
Upper part of hyoid bone

Third arch

Greater cornu of hyoid bone
Lower part of hyoid bone

Fourth arch

Thyroid cartilage
Cricoid cartilage
Arytenoid cartilage
Corniculate and Cuneiform cartilage

Q. 7

Malleus and Incus are derived from‑

 A

First arch

 B

Second arch

 C

Third arch

 D

Fourth arch

Q. 7

Malleus and Incus are derived from‑

 A

First arch

 B

Second arch

 C

Third arch

 D

Fourth arch

Ans. A

Explanation:

A i.e. First arch


Q. 8

Skeletal element of second branchial arch-

 A

Malleus

 B

Incus

 C

Meckel’s cartilage

 D

Stapes

Q. 8

Skeletal element of second branchial arch-

 A

Malleus

 B

Incus

 C

Meckel’s cartilage

 D

Stapes

Ans. D

Explanation:

D i.e. Stapes


Q. 9

Foot plate of stapes is developed from :

 A

Meckel’s cartillage

 B

Otic capsule

 C

Reicherts cartilage 

 D

Hyoid arch

Q. 9

Foot plate of stapes is developed from :

 A

Meckel’s cartillage

 B

Otic capsule

 C

Reicherts cartilage 

 D

Hyoid arch

Ans. C

Explanation:

C i.e. Reicherts cartilage 


Q. 10

Following are derived from II arch except :

 A

Malleus/ lncus

 B

Stylohyoid ligament

 C

Stylohyoid ligament

 D

Smaller cornu of hyoid

Q. 10

Following are derived from II arch except :

 A

Malleus/ lncus

 B

Stylohyoid ligament

 C

Stylohyoid ligament

 D

Smaller cornu of hyoid

Ans. A

Explanation:

A. i.e. Malleus and Incus

Foot plate of stapes develops from 2″” pharyngeal (hyoid) arch cartilage k/a Reichert cartilage. Second arch cartilage Vt formation of Stapes, Styloid process, Stylohyoid ligament, Small cornu & Superior body of hyoid bone = All “S”. First arch cartilage I/ t formation of malleus, incus, anterior ligament of malleus & spheno mandibular ligament.


Q. 11

Superior malleolar ligament connects ‑

 A

Malleus to incus

 B

Head of malleus to roof of epitympanum

 C

Incus to fossa incudis

 D

Malleus to fossa incudis

Q. 11

Superior malleolar ligament connects ‑

 A

Malleus to incus

 B

Head of malleus to roof of epitympanum

 C

Incus to fossa incudis

 D

Malleus to fossa incudis

Ans. B

Explanation:

–  Superior Malleolar fold, like the superior malleolar ligament, extends between superior surface of malleus head and superior attic wall (epitympanion)(2

Superior incudal fold, like superior incudal ligament, extends between the superior aspect of incus body & superior attic wall.

Medial incudal fold, is between long process of incus & tendon of stapedial muscle (as far as pyramidal eminence) Lateral malleolar fold is b/w neck of malleolus & scutum forming superior border of prussalc’s space.

–  Prussak’s space lies between shrapnell’s membrane & lateral malleolor ligament.

–   Anterior & posterior malleolar ligament arise from neck of malleolus from anterior & posterior aspect respectively. The anterior malleolar ligament extends from long process of malleolus towards the anterior attic wall

Discomalleolar ligament & anterior malleolar ligament damage during temporomandibular joint surgery may cause damage of middle ear. This may be a risk factor in the dissemination of infection from one area to the other. Interossicular fold lies b/w malleolus handle and long process of incus.


Q. 12

“Cone of light” is due to:

 A

Malleolar fold

 B

Handle of malleus

 C

Anterior inferior quadrant

 D

Stapes

Q. 12

“Cone of light” is due to:

 A

Malleolar fold

 B

Handle of malleus

 C

Anterior inferior quadrant

 D

Stapes

Ans. B

Explanation:

 

Cone of Light

  • Seen in anteroinferior quadrant of the tympanic membrane is actually the reflection of the light projected into the ear canal to examine it.
  • This part reflects it because it is the only part of tympanic membrane that is approximately at right angles to the meatus.
  • This difference in different parts of the tympanic membrane is due to the handle of malleus which pulls the tympanic membrane and causes it to tent inside.
  • Thus, the handle of malleus causes tenting and because of tenting the anteroinferior quardrant is at right angles to the meatus and thus reflects the light (leading to cone light).



Q. 13

Regarding stapedial reflex, which of the following is true:

 A

It helps to enhance the sound conduction in middle ear

 B

It is a protective reflex against loud sound

 C

It helps in masking the sound waves

 D

It is unilateral reflex

Q. 13

Regarding stapedial reflex, which of the following is true:

 A

It helps to enhance the sound conduction in middle ear

 B

It is a protective reflex against loud sound

 C

It helps in masking the sound waves

 D

It is unilateral reflex

Ans. B

Explanation:

Ans. is b i.e. It is a protective reflex against loud sounds 

 Stapedius muscle helps to dampen very loud sound and thus prevents noise trauma to the inner ear. It is supplied by VII nerve (facial nerve). Lesions of facial nerve lead to loss of stapedial reflex and hyperacusis or phonophobia i.e. intolerance to loud sounds. For more details see chapter – physiology of hearing and assessment of hearing loss of the guide Stapedial reflex = Acoustic reflex



Q. 14

All are components of epitympanum except:

 A

Body of incus

 B

Head of malleus

 C

Chorda tympani

 D

Footplate of stapes

Q. 14

All are components of epitympanum except:

 A

Body of incus

 B

Head of malleus

 C

Chorda tympani

 D

Footplate of stapes

Ans. D

Explanation:

Q. 15

Movement of stapes causes vibration in:

 A

Scala media

 B

Scala tympani

 C

Scala vestibuli

 D

Semicircular canal

Q. 15

Movement of stapes causes vibration in:

 A

Scala media

 B

Scala tympani

 C

Scala vestibuli

 D

Semicircular canal

Ans. C

Explanation:

Q. 16

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. 16

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. 17

Tendon of which muscle passes through the pyramid in middle ear

 A

Incus

 B

Stapedius

 C

Malleus

 D

Tensor veli palatine

Q. 17

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. 18

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. 18

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. 19

Fossa incudis is related to ‑

 A

Head of malleus

 B

Long process of incus

 C

Short process of incus

 D

Foot process of stapes

Q. 19

Fossa incudis is related to ‑

 A

Head of malleus

 B

Long process of incus

 C

Short process of incus

 D

Foot process of stapes

Ans. C

Explanation:

  • Fossa incudis contains short process of Incus.
  • Head of malleus is attached to epitympanum by ligament of head of malleus.
  • Long process of incus is attached to head of stapes.
  • Footplate of stapes lies over oval window.

Q. 20

Reichert’s cartilage derivative is ‑

 A

Malleus

 B

Inchus

 C

Stapes suprastructure

 D

Sphenomandibular ligament

Q. 20

Reichert’s cartilage derivative is ‑

 A

Malleus

 B

Inchus

 C

Stapes suprastructure

 D

Sphenomandibular ligament

Ans. C

Explanation:

The cartilage of second pharyngeal arch (hyoid arch) is known as Reicherts cartilage and contributes as :- (i) Stapes (except footplate), (ii) Styloid process, (iii) Stylohoid ligament, (iv) Lesser cornu and superior part of body of hyoid bone.

However, footplate of stapes develop from otic capsule.



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