Tympanic Membrane Of Ear/ EARDRUM
| A | Footplate of the stapes | |
| B |
Handle of the malleus |
|
| C |
Long process of the incus |
|
| D |
Tragus |
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 |
The following structure represents all the 3 components of the embryonic disc-
| A |
Tympanic membrane |
|
| B |
Retina |
|
| C |
Meninges |
|
| D |
None of the above |
A i.e. Tympanic membrane
Tympanic membrane derived from first pharyngeal membrane (which seperates 1st pharyngeal groove from 1st pharyngeal pouch) represents all three layers of embryonic disco. It develops from three sources. 1) External very thin skin is derived from ectoderm of 1st pharyngeal groove; 2) Medoderm of 1st & 2hd pharyngeal arches; 3) Internal lining is derived from endoderm of tubotympanic recess, (a derivative of 1st pharyngeal pouch).
| A |
Auriculotemporal |
|
| B |
Lesser occipital |
|
| C |
Greater occipital |
|
| D |
Parasympathetic ganglion |
A i.e. Aurico-temporal nerve
What is the color of the normal tympanic membrane?
| A |
Pearly white |
|
| B |
Gray |
|
| C |
Yellow |
|
| D |
Red |
The most mobile part of the tympanic membrane:
| A |
Central |
|
| B |
Peripheral |
|
| C |
Both |
|
| D |
None of the above |
Pars flaccida of the tympanic membrane is also called
| A |
Reissner’s membrane |
|
| B |
Shrapnell’s membrane |
|
| C |
Basilar membrane |
|
| D |
Secondary tympanic membrane |
Situated above the lateral process of malleus between the notch of Rivinus and the anterior and posterior malleal folds.
- Reissner’s membrane – Separates scala media from scala vestibuli in the inner ear
- Basilar membrane – Seen in scala media and supports the organ of corti
- Secondary Tympanic Membrane – Closes the scala tympani at the site of round window
| A | 3 mm | |
| B |
4 mm |
|
| C |
6mm |
|
| D |
2 mm |
The distance of promontory from tympanic membrane:
| A |
2 mm |
|
| B |
5 mm |
|
| C |
6 mm |
|
| D |
7 mm |
“When seen in coronal section, the cavity of the middle ear is biconcave, as the medial and lateral walls are closest to each other in the center.”
The distances separating them are:-
- Near the roof 6 mm in the epitympanum (Attic)
- In the centre 2 mm in the mesotympanum
- Near the floor 4 mm in the hypotympanum
The medial wall of the tympanic cavity is formed by the labyrinth and the lateral wall is formed by the tympanic membrane.
| A |
55 mm2 |
|
| B |
70 mm2 |
|
| C |
80 mm2 |
|
| D |
90 mm2 |
The effective diameter of the tympanic membrane:
| A |
25 mm2 |
|
| B |
30 mm2 |
|
| C |
40 mm2 |
|
| D |
45 mm2 |
Area of tympanic membrane is 90 mm2.
Effective area is 55 mrn2(approximately 2/3 of the total area).
Significance of large area of tympanic membrane – The area of tympanic is much larger than area of stapes footplate, which helps in converting sound of greater amplitude but lesser force to that of lesser amplitude and great force.
Lateral wall of middle ear is formed by:
| A |
Tegmen tympani |
|
| B |
Mastoid process |
|
| C |
Promontory |
|
| D |
Tympanic membrane |
- 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
