ANATOMY & DEVELOPMENT OF EXTERNAL EAR

2. DEVELOPMENT OF THE
EXTERNAL EAR

3. DEVELOPMENT OF
EXTERNAL EAR

7. COLLAURAL
FISTULA

9. DEVELOPMENT OF EXTERNAL
EAR SUMMARY

10. ANATOMY OF THE
EXTERNAL EAR

12. • Auricle is bounded laterally by elevated rim like prominence called the Helix.
• Anteriorly the helix bends inferiorly and posteriorly to enter over the pinna as
the Crus Helix.
• The boat shaped depression above the crus helix on the lateral aspect of pinna
is called Cymba conchae and below the crus is called Cavum conchae.
• Just anterior to Helix one can see another elevation which divide above as Supra
Crura Antihelix (upper crus) and Infra Crura Antihelix (lower curs), Thus an area
of depression is formed in between , called Triangular fossa .
• Another area which is between the supra crura Antihelix and the Helix is known
as Scaphoid fossa.
• The Cavum conchae medially enter into the lumen of External Auditory canal
(External Acoustic meatus).
• The Tragus is a separate elevation in front of External Acoustic meatus and is
formed by a separate cartilage , covered by skin.
• The space between the Crus Helix and the superior end of Tragus is called
Incisura terminalis ,which is devoid of cartilage.

18. LYMPHATIC DRAINAGE OF PINNA
The lymphatic drainage from the
posterior surface is to the lymph nodes
at the mastoid tip, from the tragus and
from the upper part of the anterior
surface to the preauricular nodes, and
from the rest of the auricle to the upper
deep cervical nodes.

24. It lies obliquely because
roof and posterior wall of
external auditory canal
shorter than the floor
and anterior wall.

25. It forms due to the light of the
otoscope that strikes the tympanic
membrane, antero-inferior quadrant of
which is at an angle of 550 to the
inferior part of external auditory canal.

31. ARTERIA NUTRICIA INCUDOMALLEA, a twig
from MIDDLE MENINGEAL ARTERY, also
supplies the inner surface of the tympanic
membrane.