GIẢI PHẨU TAI

THE UNIVERSITY TRAINING CENTER FOR HEALTH
CARE PROFESSIONALS OF HCMC
DEPARTMENT OF ANATOMY

THE EAR
Lecturer
KHOA TRAN DANG, M.D.


THE EAR

Ludwig van Beethoven
(1770-1827)

9 th Symphony (Choral)
Composed when he
was profoundly deaf.
29 june 1801


THE EAR

Outer ear
Middle ear
Inner ear


Four major divisions of auditory system – Function


THE EXTERNAL EAR

THE EXTERNAL EAR


THE EXTERNAL EAR





Three parts of outer ear
1) Pinna
2) Ear canal
3) Ear drum
Major function of outer ear
1) protection
2) amplification
3) sound localization


I. Outer ear:

THE EXTERNAL EAR

(1) Pinna (Binaural cue to sound source location)
Sound

t Right
t Left

Right
ear

Left
ear

* Different distances from source to each ear
=> different arrival times (Interaural time-difference)
and different sound level (interaural level-difference)


THE EXTERNAL EAR

I. Outer ear:

Outer ear gain

(1) Pinna (Spectral cue to sound source location)

+15°
0°
-15°

The spectral feature of sound is changed depending on the sound elevation
=> Head Related Transfer Function (HRTF)


THE EXTERNAL EAR

I. Outer ear

(1) Pinna: Cases of abnormal pinna




Anotia

Microtia (Grade II)





Microtia (Grade I)

Microtia (Grade III)


THE EXTERNAL EAR


THE EXTERNAL EAR


THE EXTERNAL EAR

I. Outer ear:
(2) Ear canal




Three parts of outer ear
1) Pinna
2) Ear canal
3) Ear drum
Major function of outer ear
1) protection
2) amplification
3) sound localization


THE EXTERNAL EAR

I. Outer ear:
(2) Transfer function of ear canal

From Gelfand (1998)


THE TEMPORAL BONE


THE SKULL


THE SKULL


THE MIDDLE EAR

THE MIDDLE EAR


THE SKULL


THE MIDDLE EAR


THE MIDDLE EAR


THE MIDDLE EAR


Middle Ear (Tympanic Cavity)
A small, air-filled, mucosa-lined cavity in the petrous
portion of the temporal bone
Flanked laterally by the eardrum and medially by a
bony wall with two openings, the oval (vestibular)
and round (cochlear) windows
Epitympanic recess -superior portion of the middle
ear containing the entrance to the masotid antrum
Pharyngotympanic tube (Eustachian tube) - connects
the middle ear to the nasopharynx - equalizes pressure
in the middle ear cavity with the external air pressure

Middle Ear (Tympanic Cavity)