The document discusses the development of the ear. It begins with the formation of the otic placode which develops into the otic pit and then the otic vesicle. The otic vesicle then forms the endolymphatic duct and sac as well as the utricular and saccular portions. The cochlea also develops from the otic vesicle. The middle ear develops from the tubotympanic recess which forms the tympanic cavity and Eustachian tube. The auditory ossicles also develop in the tympanic cavity. The external ear develops from the first branchial groove which forms the external acoustic meatus. Congenital anomalies that can result include deafness and end

1. DEVELOMPMENT OF
THE EAR
Dr Shittu LAJ

2. objectives
 1. Define otic placode, otic pit, otic vesicle,
endolymphatic duct and sac, spiral organ (of
corti), and semicircular ducts.
 2. Discuss the embryological basis of the
following congenital anomalies;
endolymphaticus, deafness etc.

3. THE EAR
 - Three Anatomical Parts -
 - external
 - middle
 - internal

4. Development of the Inner Ear
 Early 4th week - From Myelencephalon
 Otic placode  otic pit  otic vesicle (otocyst)
 Endolymphatic duct and sac  utricular and
saccular portions
 Cochlea

6. Development of Middle
Ear:
 Tubotympanic recess  (Dis.) Tympanic
cavity  (Prox.) Eustachian tube
 Tympanic Cavity  Auditory ossicles
(Malleus, Incus and Stapes)
 Mastoid antrum and mastoid processes

7. Development of External Ear:
 The external acoustic Meatus - develops from
the dorsal end of the first branchial groove.
 -NB: Primordium of Tympanic membrane is the
first branchial membrane

8. Congenital Anomalies of the
Ear.
 Hearing loss/deafness
 Endolymphaticus

9.  Tympanic membrane develops from -
ectoderm
 - mesoderm
 - endoderm
 - auricle develops from six mesenchymal
swellings
 - auricular hillocks

10.  Tympanic membrane develops from -
ectoderm
 - mesoderm
 - endoderm
 - auricle develops from six mesenchymal
swellings
 - auricular hillocks