Auditory Ossicles

Auditory Ossicles

Q. 1

Which of the following attains adult size before birth?

 A

Mastoid antrum

 B

Orbit

 C

Ear ossicles

 D

Cornea

Q. 1

Which of the following attains adult size before birth?

 A

Mastoid antrum

 B

Orbit

 C

Ear ossicles

 D

Cornea

Ans. C

Explanation:

Q. 2

Which of the following attains adult size before birth?

 A

Ear Ossicles

 B

Maxilla

 C

Mastoid Process

 D

Parietal bone

Q. 2

Which of the following attains adult size before birth?

 A

Ear Ossicles

 B

Maxilla

 C

Mastoid Process

 D

Parietal bone

Ans. A

Explanation:

Ear Ossicles 

“The tympanic cavity and mastoid antrum , auditory ossicles and structures of the internal ear are all almost fully developed at birth and subsequently alter little.” 


Q. 3

All are of adult size at birth except?

 A

Mastoid antrum

 B

Ear Ossicles

 C

Tyrnpanic cavity

 D

Maxillary antrum

Q. 3

All are of adult size at birth except?

 A

Mastoid antrum

 B

Ear Ossicles

 C

Tyrnpanic cavity

 D

Maxillary antrum

Ans. D

Explanation:

The tympanic cavity and mastoid antrum , auditory ossicles and structures of the internal ear are all almost fully developed at birth and subsequently alter little.


Q. 4

Which of the following attains adult size before birth?

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Parietal bone

Q. 4

Which of the following attains adult size before birth?

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Parietal bone

Ans. A

Explanation:

Q. 5

Otosclerosis mostly affects:

 A

Malleus

 B

Stapes

 C

Incus

 D

Tympanic membrane

Q. 5

Otosclerosis mostly affects:

 A

Malleus

 B

Stapes

 C

Incus

 D

Tympanic membrane

Ans. B

Explanation:

Q. 6

What is the type of joints between the ossicles of the ear?

 A

Fibrous joints

 B

Synovial joints

 C

Primary cartilaginous

 D

Secondary cartilaginous joints

Q. 6

What is the type of joints between the ossicles of the ear?

 A

Fibrous joints

 B

Synovial joints

 C

Primary cartilaginous

 D

Secondary cartilaginous joints

Ans. B

Explanation:

Q. 7

Which of the following conditions is associated with maximum hearing loss?

 A

Otitis media with effusion

 B

Partial fixation of the stapes footplate

 C

Ossicular disruption with intact tympanic membrane

 D

Disruption of malleus and incus as well tympanic membrane

Q. 7

Which of the following conditions is associated with maximum hearing loss?

 A

Otitis media with effusion

 B

Partial fixation of the stapes footplate

 C

Ossicular disruption with intact tympanic membrane

 D

Disruption of malleus and incus as well tympanic membrane

Ans. C

Explanation:

Maximum hearing loss occur when there is ossicular interruption with intact tympanic membrane (54dB).

Ossicular interruption with perforation result in 38dB hearing loss, hearing loss in ottitis media with effusion averages about 26-30 dB.

Partial or complete fixation of the stapes results in conductive hearing loss that ranges from 5dB to 60dB.


Q. 8

Which of the following attains adult size before birth?

 A

Mastoid antrum

 B

Orbit

 C

Ear ossicles

 D

Cornea

Q. 8

Which of the following attains adult size before birth?

 A

Mastoid antrum

 B

Orbit

 C

Ear ossicles

 D

Cornea

Ans. C

Explanation:

By 15 weeks, the ossicles have attained adult size, and ossification begins, first in the incus and last in the stapes.

At the same time, the tensor tympani and stapedius muscles develop from the mesenchyme of the first and second branchial arches, respectively.

The adult configuration of the malleus and incus is achieved by 20 weeks, whereas the stapes continues to evolve into its adult dimensions into the 32nd week. 

 

Q. 9

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. 9

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. 10

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. 10

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. 11

Otosclerosis mostly affects:

 A

Malleus

 B

Stapes

 C

Incus

 D

Tympanic membrane

Q. 11

Otosclerosis mostly affects:

 A

Malleus

 B

Stapes

 C

Incus

 D

Tympanic membrane

Ans. B

Explanation:

  • Otosclerosis is caused by immobility of the stapes.
  • Its most distinctive feature is conductive hearing loss, but sensorineural hearing loss and vertigo are also common; 
  • tinnitus is infrequent.
  • Otosclerosis is suggested by a positive family history, 
  • a tendency toward onset at an earlier age, 
  • the presence of conductive hearing loss, or
  •  bilateral symmetric auditory impairment
  • Treatment with a combination of sodium fluoride, calcium gluconate, and vitamin D may be effective. If not, surgical stapedectomy should be considered.
 

Q. 12

About skull of newborn, all of the following statements are TRUE, EXCEPT:

 A

Paranasal sinuses are absent

 B

Absent diploic spaces

 C

Middle ear ossicles are of same size as in adults

 D

Mastoid process is not completely formed

Q. 12

About skull of newborn, all of the following statements are TRUE, EXCEPT:

 A

Paranasal sinuses are absent

 B

Absent diploic spaces

 C

Middle ear ossicles are of same size as in adults

 D

Mastoid process is not completely formed

Ans. A

Explanation:

All paranasal sinuses are present to varying degrees in newborn. Ethmoid sinuses are first to fully develop followed in order by maxillary, sphenoid and frontal sinuses. 
 
The auditory ossicles malleus, incus and stapes reach the adult size as early as sixth month of fetal life. The oval window and round window are the same size in the newborn infant as in the adult. The tympanic membrane completes its full growth by birth. 
 
Mastoid process is not completely formed by birth, so the facial nerve coming out of the stylomastoid foramen is not protected by the mastoid process. Hence it can be pressed by forceps in case of forceps delivery leading to temporary facial paralysis.
 

Q. 13

Organogenesis take place in the first trimester. Which of the following structure attains adult size before birth?

 A

Mastoid process

 B

Ear ossicles

 C

Maxilla

 D

Parietal

Q. 13

Organogenesis take place in the first trimester. Which of the following structure attains adult size before birth?

 A

Mastoid process

 B

Ear ossicles

 C

Maxilla

 D

Parietal

Ans. B

Explanation:

By 12 to 15 weeks, the ossicles are more clearly differentiated and approximate adult size. By the sixteenth week of gestation, the ossicles reach adult size. Shortly following this stage, ossification begins, first in the incus and last in the stapes.

The external auditory meatus and tympanic membrane also reach adult size before term.


Q. 14

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. 14

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. 15

Malleus and Incus are derived from‑

 A

First arch

 B

Second arch

 C

Third arch

 D

Fourth arch

Q. 15

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. 16

Skeletal element of second branchial arch-

 A

Malleus

 B

Incus

 C

Meckel’s cartilage

 D

Stapes

Q. 16

Skeletal element of second branchial arch-

 A

Malleus

 B

Incus

 C

Meckel’s cartilage

 D

Stapes

Ans. D

Explanation:

D i.e. Stapes


Q. 17

Bone not present at birth-

 A

Malleus

 B

Incus

 C

Stapes

 D

Petrous temporal

Q. 17

Bone not present at birth-

 A

Malleus

 B

Incus

 C

Stapes

 D

Petrous temporal

Ans. D

Explanation:

D i.e. Petrous temporal


Q. 18

All are of adult size at birth except:

 A

Mastoid antrum

 B

Ear Ossicles

 C

Tympanic cavity

 D

Maxillary antrum & orbit

Q. 18

All are of adult size at birth except:

 A

Mastoid antrum

 B

Ear Ossicles

 C

Tympanic cavity

 D

Maxillary antrum & orbit

Ans. D

Explanation:

D i.e. Maxillary antrum & orbit 

  • The tympanic cavity, Tympanic (or mastoid) antrum, auditory (ear) osicles, and internal ear structures are all almost fully developed (i.e. of adult size) at birth and subsequently alter little. 
  • Mastoid antrum is an air sinus in the petrous part of temporal bone. Its adult capacity is variable, but on average is 1 mL, with a general diameter of 10 nun. Unlike other air sinuses in the skull (e.g. maxillary antrum), it is present at birth, and indeed of almost adult sizeQ, although it is at a higher level relative to the external acoustic meatus than it is in adults.
  • The lateral wall of mastoid antrum, which offers the usual surgical approach, is only 2 mm thick at birth but increases at an average of 1 mm a year, attaining final thickness of 12-15 mm.
  • Though the mastoid process antrum is well developed at birth, the mastoid process is absent at birth and develop in 2,0 year. The mastoid air cells are merely minute antral diverticula it birth. As the mastoid develops in 2nd year, the air cells gradually extend into it and by the 4th year they are well formed, although their greatest growth occurs at puberty (Gray’s-626). But BDC – 30 & Gray’s -417 say mastoid processes do not develop until the 2nd year & they are invaded by air cells (pneumatized i.e. mastoid air cells appear) during 6th year.
  • The thinness of lateral antral wall & absence or under development of mastoid process means that the stylomastoid foramen & emerging facial nerve are very superficially situated. In adults lateral wall of mastoid antrum corresponds to macewen’s suprameatal triangle.
  • The paranasal sinuses are rudimentary or absent and only the maxillary sinuses are identifiable at birth
  • Ethmoid, orbital and upper nasal cavities have almost completed growth by the 7th year, (Grays- 418). Orbit reaches its full adult size by 15-16 years of age (David Taylor – 205)
  • At birth bones of cranial vault are unilaminar & lack diploe but the tabular structure with intervening diploe is generally apparent by about 4th year. Differentiation reach maximum by about 35 years.

Q. 19

Which of the following attains adult size before birth:

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Mastoid

Q. 19

Which of the following attains adult size before birth:

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Mastoid

Ans. A

Explanation:

A i.e. Ear ossicles

Auditory (ear) ossicles attain full adult size at (or before) birth. Although mastoid antrum (air sinus) is well developed (& of adult size) at birth, but mastoid process & air cells develop later.


Q. 20

What is the type of joints between the ossicles of ear?

 A

Fibrous joints

 B

Primary cartilaginous

 C

Secondary cartilaginous joints

 D

Synovial joints

Q. 20

What is the type of joints between the ossicles of ear?

 A

Fibrous joints

 B

Primary cartilaginous

 C

Secondary cartilaginous joints

 D

Synovial joints

Ans. D

Explanation:

D i.e. Synovial joint


Q. 21

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. 21

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. 22

“Cone of light” is due to:

 A

Malleolar fold

 B

Handle of malleus

 C

Anterior inferior quadrant

 D

Stapes

Q. 22

“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. 23

All are components of epitympanum except:

 A

Body of incus

 B

Head of malleus

 C

Chorda tympani

 D

Footplate of stapes

Q. 23

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. 24

What is the type of joint between the ossicles of ear?

 A

Fibrous joint

 B

Primary cartilaginous

 C

Secondary cartilaginous 

 D

Synovial joint

Q. 24

What is the type of joint between the ossicles of ear?

 A

Fibrous joint

 B

Primary cartilaginous

 C

Secondary cartilaginous 

 D

Synovial joint

Ans. D

Explanation:

Q. 25

Which of the following attains adult size before birth? 

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Parietal bone

Q. 25

Which of the following attains adult size before birth? 

 A

Ear ossicles

 B

Maxilla

 C

Mastoid

 D

Parietal bone

Ans. A

Explanation:

The ossicles begins to form during 4th week of gestation from the mesenchymal tissue.

They originate as cartilaginous models that reach adult size by the 18th week of gestation.

Ossification of malleus begins at 15th week gestation, while stapes begins to ossify at 18th week of gestation. At birth. the ossicles are of nearly adult size.

 



Q. 26

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. 26

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. 27

Features of moderately retracted tympanic membrane are all except:

 A

Handle of malleus appearance foreshortened

 B

Cone of light is absent or interrupted

 C

Lateral process of malleus becomes more prominent

 D

None

Q. 27

Features of moderately retracted tympanic membrane are all except:

 A

Handle of malleus appearance foreshortened

 B

Cone of light is absent or interrupted

 C

Lateral process of malleus becomes more prominent

 D

None

Ans. D

Explanation:

Q. 28

Ossicle M/C involved in CSOM:

 A

Stapes

 B

Long process of incus

 C

Head of malleus

 D

Handle of malleus

Q. 28

Ossicle M/C involved in CSOM:

 A

Stapes

 B

Long process of incus

 C

Head of malleus

 D

Handle of malleus

Ans. B

Explanation:

Q. 29

Radical mastoidectomy includes all except: 

 A

Closure of the auditory tube

 B

Ossicles removed

 C

Cochlea removed

 D

Exteriorisation of mastoid

Q. 29

Radical mastoidectomy includes all except: 

 A

Closure of the auditory tube

 B

Ossicles removed

 C

Cochlea removed

 D

Exteriorisation of mastoid

Ans. C

Explanation:

Q. 30

All are autosomal recessive EXCEPT:

September 2004

 A

Sickle cell anemia

 B

Phenylketonuria

 C

Marfan’s syndrome

 D

Wilson’s disease

Q. 30

All are autosomal recessive EXCEPT:

September 2004

 A

Sickle cell anemia

 B

Phenylketonuria

 C

Marfan’s syndrome

 D

Wilson’s disease

Ans. C

Explanation:

Ans. C i.e. Marfan’s syndrome

Marfan syndrome is a disorder of connective tissue, manifested principally by changes in the skeleton, eyes, and cardiovascular system. It is transmitted by autosomal dominant inheritance.


Q. 31

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. 31

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. 32

Malleus and incus are derived from ‑

 A

1st Arch

 B

2nd Arch

 C

3rd Arch

 D

4th Arch

Q. 32

Malleus and incus are derived from ‑

 A

1st Arch

 B

2nd Arch

 C

3rd Arch

 D

4th Arch

Ans. A

Explanation:

Ans. is ‘a’ i.e., 1st Arch


Q. 33

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. 33

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. 34

Reichert’s cartilage derivative is ‑

 A

Malleus

 B

Inchus

 C

Stapes suprastructure

 D

Sphenomandibular ligament

Q. 34

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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