External ear

EXTERNAL EAR

Q. 1

Ear pinna develops from ____________

 A

Ectoderm

 B

Endoderm

 C

Mesoderm

 D

All 

Q. 1

Ear pinna develops from ____________

 A

Ectoderm

 B

Endoderm

 C

Mesoderm

 D

All 

Ans. A

Explanation:

 Ans:A.)Ectoderm

  • First branchial cleft is the precursor of external auditory canal.
  • Around the sixth week of embryonic life, a series of six tubercles appear around the first branchial cleft

 

  • Branchial clefts are ectodermal in origin.

Q. 2

Which of the following is formed at birth?

 A

Mastoid process

 B

Pinna

 C

Otic capsule

 D

Secondary areola

Q. 2

Which of the following is formed at birth?

 A

Mastoid process

 B

Pinna

 C

Otic capsule

 D

Secondary areola

Ans. B

Explanation:

Q. 3

The presence of white fibrocartilage is a feature of all of the following, EXCEPT:

 A

Acetabular labrum

 B

Intervertebral disc

 C

Meniscus

 D

Pinna

Q. 3

The presence of white fibrocartilage is a feature of all of the following, EXCEPT:

 A

Acetabular labrum

 B

Intervertebral disc

 C

Meniscus

 D

Pinna

Ans. D

Explanation:

Pinna is composed of a thin plate of yellow elastic cartilage, covered with integument

It is connected to the surrounding parts by ligaments and muscles; and to the commencement of the external acoustic meatus by fibrous tissue.


Q. 4

Fibrocartilage is present in all, EXCEPT:

 A

Pinna

 B

Symphysis pubis

 C

Intervertebral disc

 D

Menisci of knee joint

Q. 4

Fibrocartilage is present in all, EXCEPT:

 A

Pinna

 B

Symphysis pubis

 C

Intervertebral disc

 D

Menisci of knee joint

Ans. A

Explanation:

Fibrocartilage is a white opaque structure due to dense collage fibres (type I and II).

When a fibrous tissue is subjected to pressure it is replaced by fibrocartilage.

It is seen in joints, symphysis, intervertebral discs, menisci and labra (shoulder joint and hip joint).

Pinna is a type of elastic cartilage. Elastic cartilages are seen at sites concerned with production or reception of sounds eg external acoustic meatus (lateral part), auditory tube and epiglottis.


Q. 5

True regarding the development of ear:

 A

Eustachian tube opens at the level of interior turbinate

 B

Pinna develops from the cleft of Ist arch

 C

Growth of the inner- ear completed by 4th month

 D

All

Q. 5

True regarding the development of ear:

 A

Eustachian tube opens at the level of interior turbinate

 B

Pinna develops from the cleft of Ist arch

 C

Growth of the inner- ear completed by 4th month

 D

All

Ans. D

Explanation:

A i.e. Eustachian tube opens at the level of inferior turbinate; B i.e. Pinna develops from the cleft of arch; C i.e. Growth of inner ear completed by 4th month

Eustachian tube connects tympanic cavity with nasopharynx. It is about 36cm long in adults and runs downwards, forwards & medially at an angle of 45° with horizontal from bony tympanic end to slit like pharyngeal end. Tympanic end is in the anterior wall of middle ear, just above the level of floor. While nasopharyngeal end is situated in the lateral wall about 1 -1.25 cm behind the posterior end of inferiro turbinateQ


Q. 6

Sensory nerve supply of pinna is :

 A

Mandibular nerve

 B

Maxillary nerve

 C

Facial nerve

 D

Abducent nerve

Q. 6

Sensory nerve supply of pinna is :

 A

Mandibular nerve

 B

Maxillary nerve

 C

Facial nerve

 D

Abducent nerve

Ans. A

Explanation:

Auriculotemporal nerve, a branch of mandibular nerve (V3)(2 supplies the external acoustic meatus, external surface of auricle above this, skin of temporal region and TM joint.


Q. 7

Major part of the skin of pinna is supplied by:

 A

Aurculo temporal nerve

 B

Auricular branch of the vagus

 C

Posterior auricular nerve

 D

Great auricular nerve

Q. 7

Major part of the skin of pinna is supplied by:

 A

Aurculo temporal nerve

 B

Auricular branch of the vagus

 C

Posterior auricular nerve

 D

Great auricular nerve

Ans. D

Explanation:

D i.e. Great auricular


Q. 8

Which of the following does not give sensory supply to the pinna:

 A

Auricotemporal Nerve

 B

Great Auricular Nerve

 C

Lesser Occipital Nerve

 D

Tympanic branch of Glossopharyngeal Nerve

Q. 8

Which of the following does not give sensory supply to the pinna:

 A

Auricotemporal Nerve

 B

Great Auricular Nerve

 C

Lesser Occipital Nerve

 D

Tympanic branch of Glossopharyngeal Nerve

Ans. D

Explanation:

Tympanic branch of glossopharyngeal (IX) nerve or Jacobson’s nerve supplies the medial (inner) surface of tympanic membrane. It does not supply pinnaQ.

Main nerves supplying the skin of auricle (pinna) are great auricular nerve (c2, CP and auriculo temporal nerve (V3)(2 with a small contribution from lesser occipital nerve, (C2), auricular branch of vagus (X) nerve or Arnold’s nerve and facial nerve.

The great auricular supplies the whole of the cranial (medial /back) surface of auricle (C2, with a little overlap from the lesser occipital at the top) and the posterior part of lateral (front) surface (helix, anthelix, and lobule).

The auriculo temporal nerve (br. of CNV3) supplies the upper part of lateral surface , skin of auricle anterior to external acoustic meatus, tragus, crus & adjacent part of helix and most of meatal skin.

Auricular branch of vagus (Arnold’s nerve) supplies skin on the concavity of concha & posterior part of eminentia , posterior wall & floor of meatus and adjoining tympanic membrane.


Q. 9

Skin over pinna is fixed:

 A

Firmly on both sides

 B

Loosely on medial side

 C

Loosely on lateral side

 D

Loosely on both side

Q. 9

Skin over pinna is fixed:

 A

Firmly on both sides

 B

Loosely on medial side

 C

Loosely on lateral side

 D

Loosely on both side

Ans. B

Explanation:

Skin over the pinna is closely adherent to the perichondrium on the lateral surface while it is loosely attached on the medial surface.


Q. 10

Pinna develops from:

 A

1st pharyngeal arch

 B

1st and 3rd pharyngeal arch

 C

1st and 2nd pharyngeal arch

 D

2nd pharyngeal arch

Q. 10

Pinna develops from:

 A

1st pharyngeal arch

 B

1st and 3rd pharyngeal arch

 C

1st and 2nd pharyngeal arch

 D

2nd pharyngeal arch

Ans. C

Explanation:


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