Loading....
Coupon Accepted Successfully!

ENT

Open Flashcards

Embryology and Anatomy of Ear

Question
40 out of 70
 

About Eustachian tube: [PGI June 02]



A 24 mm in length

B Outer 1 13rds is cartilaginous

C Inner 2/3rds is bony

D Inner 2/3rds is cartilaginous

E Opens during swallowing

Ans. D and E. Inner 2/3rd is Cartilaginous; and Opens during swallowing

o The Eustachian tube/auditory tube in the adult is 36 mm in length. From its pharyngeal end, it runs upwards, laterally and backward.

o In infants, the tube is shorter, wider and is more horizontal.

o It has two parts-a pharyngeal cartilaginous part which forms 2/3rd (24 mm) of its length (. inner or medial part) and a tympanic bony part which forms remaining 1/3rd (outer or lateral part). (12 mm). This is just reverse of externalaudltory canal

Remember: Mnemonic ICE 2/3: Inner part Cartilaginous in Eustachian tube and forms 2/3 part.

The two parts meet at isthmus which is the narrowest part of tube.

The fibers of origin of tensor palati muscles are attached to lateral wall of the tube. Contraction of this muscle during swallowing, yawning and sneezing opens the tube and this helps in maintaining equality of air pressure on both sides of tympanic membrane. Contraction of levator palati muscles which runs below the floor of cartilaginous part also helps in opening the tube.

It is lined by pseudostratitified columnar ciliated epithelium (cartilaginous part contains numerous mucous glands).

Embryology and Anatomy of Ear Flashcard List

70 flashcards
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
21)
22)
23)
24)
25)
26)
27)
28)
29)
30)
31)
32)
33)
34)
35)
36)
37)
38)
39)
40)
41)
42)
43)
44)
45)
46)
47)
48)
49)
50)
51)
52)
53)
54)
55)
56)
57)
58)
59)
60)
61)
62)
63)
64)
65)
66)
67)
68)
69)
70)