embryology

1. AN 43.4
Development of Eye & Ear
Dr. Suresh Managutti MBBS MD Anatomy
Associate Professor
Department of Anatomy
SDM College of Medical Sciences & Hospital, Dharwad

2. Development of Eye

3. Development of the optic vesicle and lens placode

4. Formation and development of optic vesicle

5. Development of the lens vesicle and invagination into
the optic cup

6. Development of choroid fissure and hyaloid vessels

7. Stages in the development of Retina

8. Developmental stages in the formation of lens

9. Development of the coats of the eye
A. Development of
retinal layers
B. Development of
sclera, choroid,
ciliary body and iris

10. Formation of anterior and posterior chambers

11. Development of eyelids, conjunctival sac and lacrimal gland

12. Development of nasolacrimal duct and lacrimal sac

13. Adult components of eye derived from various embryonic structures
Embryonic structures Adult derivatives
Neuroectoderm of forebrain
a) Optic cup Retina
Dilator pupillae
Sphincter pupillae
Epithelium of iris and ciliary body
b) Optic stalk Optic nerve
Surface ectoderm Lens
Anterior epithelium of cornea
Mesoderm Sclera
Substantia propria and posterior epithelium of cornea
Choroid, ciliary body and stroma of iris
Vitreous body
Central artery and vein of retina
Extraocular muscles

14. Clinical correlation
•Retinal detachment
•Papilledema
•Congenital cataract – Rubella,
toxoplasmosis, Down’s syndrome,
Galactosemia
•Color of the iris –brown, blue

15. Clinical correlation
Congenital anomalies of the eyeball
• Anophthalmos
• Microphthalmos- TORCH
• Cyclopia, Proboscis, Synophthalmia
• Persistent pupillary membrane
• Coloboma of the iris
• Congenital aniridia
• Congenital glaucoma-buphthalmos
• Congenital aphakia

16. Clinical correlation
Anomalies of the eyelids
• Coloboma of the eyelid- upper eyelid
• Entropion, Ectropion
• Congenital ptosis
• Epicanthus
• Cryptophthalmos- congenital absence of eyelids

17. Clinical correlation
Anomalies of lacrimal apparatus
• Absence of lacrimal gland
• Absence of lacrimal apparatus- complete or partial
• Supernumerary puncta or canaliculi
• Presence of cysts in any part of lacrimal apparatus
commonly in punctum

18. Some congenital anomalies of the eye

19. Facts to remember
• First indication of development of eye- formation of optic sulcus(groove)
• Most important refractive medium of eye- cornea
• Optic nerve is a tract of diencephalon and not a peripheral nerve because
- Myelinated by oligodendrocytes
- Surrounded by meninges and subarachnoid space with CSF
- Not capable of regeneration if transected

20. Development of Ear

21. Development of external auditory meatus

22. Development of auricle(pinna)

23. Development of tympanic membrane

24. Development of middle ear (tympanum) and
pharyngotympanic tube

25. Formation of the otic vesicle

26. Development of the membranous labyrinth

27. Development of peri lymphatic spaces around the cochlear duct

28. Cross section of cochlear canal showing boundaries of
cochlear duct and Organ of Corti within it

29. Derivatives of various components of the ear
Embryonic structure Adult derivatives
Internal ear
Saccular portion
Utricular portion
Saccule & cochlear duct
Utricle, semi-circular canals (ducts), endolymphatic duct and sac
Middle ear
First pharyngeal arch
Second pharyngeal arch
First pharyngeal pouch
First pharyngeal membrane
Malleus, incus and tensor tympani muscle
Stapes and stapedius muscle
Pharyngotympanic tube and tympanum (middle ear cavity)
Tympanic membrane
External ear
First pharyngeal cleft
Auricular hillocks in mandibular and hyoid
arches
External auditory meatus
Auricle (Pinna)

30. Clinical correlation
Congenital anomalies of external ear
• Anotia- absence of auricle
• Preauricular appendages and pits – Trisomy 13, 18, 21
• Atresia of external auditory meatus- congenital
deafness- first arch syndrome

31. Facts to remember
• Developmentally internal ear appears first- begins at 4th week (9th
week ends)
• Internal ear, tympanic cavity, mastoid antrum and ear ossicles
attain adult size at birth
• Ear is most sensitive to teratogens at 4-9 weeks
• Most common cause of congenital deafness- failure of
canalization of meatal plate
• External, internal and middle ear develop from 3 distinctively
different sources