This document discusses the development of the pharyngeal arches. It begins by introducing the pharyngeal arches and their components, which include ectoderm, endoderm, mesoderm and neural crest cells. It then describes the formation and derivatives of each of the first, second, third, fourth and sixth pharyngeal arches. This includes the muscles, bones, cartilages and other structures derived from each arch. It also discusses the fate of the pharyngeal pouches and clefts. Finally, it mentions some clinical correlations involving abnormalities in pharyngeal arch development.

1. PRESENTED BY
DR. MEGHA BAHAL
MDS I YEAR (OMR)

3. •INTRODUCTION
•DEVELOPMENT OF PHARYNGEAL ARCHES
•STRUCTURE OF PHARYNGEAL ARCHES
(CELLULAR COMPONENTS
•PATTERNING OF PHARYNGEAL ARCHES
•NEURAL CREST CELLS
•COMPONENETS OF PHARYNGEAL ARCHES
•DERIVATIVES OF PHARYNGEAL ARCHES
•FATE OF ENDODERMAL POUCHES
•FATE OF ECTODERMAL CLEFTS
•CLINICAL CORRELATIONS
•REFERENCES

6. •After the formation of Foregut , it is bounded VENTRALLY by
PERICARDIUM, and DORSALLY by DEVELOPING BRAIN
•Cranially it is first separated from the STOMODEUM by the
BUCCOPHARYNGEAL MEMBRANE. When this membrane breaks
down the foregut opens to the exterior through the
stomatodeum
•At this stage the head is represented by the bulging caused by
the developing brain , while the PERICARDIUM may be
considered as the region of the future thorax
•The NECK is formed by the elongation of the region between
the stomatodeum and the pericardium
This is formed by the PHARYNGEAL ARCHES
•PHARYNGEAL ARCHES are ROD LIKE thickenings of
mesoderm present in the
Wall of foregut

9. •PHARYNGEAL ARCHES : A series of FIVE paired swellings that
surround the embryonic foregut from day 25
to day 35 of development
•PHARYNGEAL GROOVES: The ECTODERMALLY lined depression
between the pharyngeal arches
•PHARYNGEAL POUCHES: The ENDODERMALLY lined depression
• between the pharyngeal arches .
•PHARYNGEAL MEMBRANE: A thin membrane composed of ,
composed of ECTODERM and ENDODERM,
formed as a result of a contact between a
pharyngeal groove and a corresponding
pharyngeal pouch.

11. Embryologically the PHARYNGEAL ARCHES has its origin in a
series of BULGES that form on the LATERAL SURFACE OF THE
EMBRYONIC HEAD .
These structures are composed of a number of disparate
embryonic cell types : ENDODERM , ECTODERM , NEURAL
CREST and MESODERM , whose development must be
coordinated to generate the functional adult apparatus.

13. PHARYNGEAL ARCHES are formed by cells that are derived
from the ECTODERM , ENDODERM , MESODERM , and NEURAL
CREST CELLS.
ECTODERM
Lines the external surfaces of the pharyngeal arches , the
ectodermally lined depressions between the pharyngeal
arches called PHARYNGEAL GROOVES.
ENDODERM
Lines the internal foregut surfaces of the pharyngeal arches .
The endodermally lined depression between the pharyngeal
arches is called PHARYNGEAL POUCHES.
MESODERM
The AXIAL MESODERM immediately caudal to the
buccopharyngeal membrane is called the
PRECHORDAL PLATE . This plate lies anterior to the
NOTOCHORDAL PROCESS and is intimately fused with the area
of thickened endoderm anterior to it which is a part of future
buccopharyngeal membrane.

14. NEURAL CREST CELLS
Migration of neural crest cells in the trunk occurs after closure of
neural tube and the principal Pathway of migration is through the
anterior portion of somites.

15. MID BRAIN NEURAL
CREST CELLS
HIND BRAIN NEURAL
CREST CELLS
Moves around the developing
forebrain and behind the eye
Into the FIRST PHARYNGEAL
ARCH.
Contributes primarily to
arches 2, 3,4 and 6.
Neural crest cells that
migrate later from
The mid and hind brain
regions do not
move as far away from the
neural tube and
give rise to Meninges and
ganglia

16. SEGMENTATION gives us a repeating structure A BASIC
PLAN.....
SOMITES appear from day19-day 35.
PHARYNGEAL ARCHES appear from day 20 to day 35.
RHOMBOMERES eight segments of the neural tube in the
hindbrain appear during the Development of urogenital
system.

23. •Develops into bilateral maxillary and mandibular processes
mesodermal cells create
1. MASSETER MUSCLE
2. TEMPORALIS MUSCLE
3. LATERAL PYERYGOID MUSCLE
4. MEDIAL PTERYGOID MUSCLE
5. MYLOHYOID MUSCLE
6. ANTERIOR BODY OF DIGASTRIC MUSCLE
7. TENSOR TYMPANI MUSCLE
8. TENSOR VELI PALATINI MUSCLE
Neural crest cells contribute to
1. MAXILLA
2. SQUAMOUS PORTION OF TEMPORAL BONE
3. ZYGOMA

24. 4.MANDIBLE
5. MALLEUS
6.INCUS
CARTILAGES include MECKELS CARTILAGE
CONNECTIVE TISSUE exist in the form of
1. SPHENOMANDIBULAR LIGAMENT
2. ANTERIOR LIGAMENT OF MALLEUS
NERVE innervating is TRIGEMINAL NERVE

25. MESODERM produces
1. MUSCLES OF FACIAL EXPRESSION
2. POSTERIOR BODY OF DIGASTRIC MUSCLE
3. STYLOHYOID MUSCLE
4. STAPEDIUS MUSCLE
BONES from the neural crest include:
1. LESSER CORNU OF THE HYOID
2. SUPERIOR PART OF HYOID BODY
3. STYLOID PROCESS
4. STAPES
CARTILAGES include REICHARTS CARTILAGE
CONNECTIVE TISSUE include STYLOHYOID LIGAMENT and
TONSIL
NERVE innervating FACIAL NERVE

26. MUSCLE produced is STYLOPHARYNGEUS MUSCLE
BONES from NEURAL CREST CELL involve
1. GREATER CORNU OF HYOID BONE
2. INFERIOR PART OF THE HYOID BODY
NO CARTILAGE structures present
CONNECTIVE TISSUE is seen in the
1. THYMUS
2. INFERIOR PARATHYROID
NERVE innervating GLOSSOPHARYNGEAL NERVE

27. MESODERM of this arch contributes
1. UVULA MUSCLE
2. LEVATOR VELI PALATINI MUSCLE
3. PALATOPHARYNGEUS MUSCLE
4. PALATOGLOSSUS MUSCLE
5. SUPERIOR , MIDDLE , AND INFERIOR PHARYNGEAL CONSTRICTOR
MUSCLE
6. SALPINGOPHARYNGEUS MUSCLE
7. CRICOTHYROID MUSCLE
NO SKELETAL STRUCTURES
CARTILAGE derived is THYROID CARTILAGE and EPIGLOTTIS
CONNECTIVE TISSUE involves
1. SUPERIOR PARATHYROID GLAND
2. THYROID GLAND
NERVE innervating is VAGUS NERVE

28. This arch is not worth mentioning since it form with the others
In the very early stages and the regresses almost immediately
When visible, it looks like a very small appendage between the
Fourth and sixth arches
MESODERMAL MUSCULATURE involves
1. THYROARYTENOID VOCALIS MUSCLE
2. ARYEPIGLOTTIS MUSCLE
3. THYROEPIGLOTTIS MUSCLE
4. LATERAL , OBLIQUE , TRANSVERSE AND POSTERIOR
ARYTENOID MUSCLE
NO BONES and NO CONNECTIVE TISSUE
CARTILAGES involve ARYTENOID CRICOID CUNEIFORM AND
CORNICULATE
NERVES innervating is VAGUS NERVE

31. FIRST POUCH
•VENTRAL obliterated by the formation of TONGUE
•DORSAL part forms DIVERTICULUM called TUBOTYMPANIC
RECESS . This Forms AUDITORY TUBE, MIDDLE EAR CAVITY,
TYMPANIC ANTRUM
SECOND POUCH
• TONSIL
• TUBOTYMPANIC RECESS
THIRD POUCJ
• INFERIOR PARATHYROID GLANDS
• THYMUS
FOURTH POUCH
• SUPERIOR PARATHYROID GLANDS
• THYROID GLANDS

32. FIFTH OR ULTIMOBRANCHIAL POUCH
•In some species it forms the ULTIMOBRANCHIAL BODY
•In man it is controversial , it incorporates into the fourth pouch
forming CAUDAL PHARYNGEAL COMPLEX

33. When the second pharyngeal arch fails to grow caudally over
the third and fourth arches leaving remnants of second , third ,
and fourth clefts in contact with the surface by a narrow canal.
Such a fistula on the lateral aspect of the neck directly anterior
to the STERNOCLEIDOMASTOID MUSCLE provides drainage of
the LATERAL CERVICAL CYST
These are below THE ANGLE OF THE JAW

35. •TREACHER COLLINS SYNDROME
•ROBIN SEQUENCE
•DIGEORGES ANOMALY
•GOLDENHAR SYNDROME

36. 1. LANGMANS MEDICAL EMBRYOLOGY 11TH EDITION
TW SADLER
2. HUMAN EMBRYOLOGY Inderbeer Singh 7TH EDITION
3. EMBRYOLOGY – ULRICH DREWS
4. ORBANS DENTAL HISTOLOGY
5. TENCATES ORAL HISTOLOGY
6. BOOK OF ANATOMY –BD Chaurasia VOLUME 3
•ARTICLES
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Nov ;3(6):403-418
2. GRAHAM.A , THE DEVELOPMENT
AND EVOLUTION OF PHARYNGEAL ARCHES JOURNAL OF
ANATOMY 2001:JUL –AUG 199(Pt 1-2) : 133-141
3. GRAHAM.A , Development of pharyngeal arches AMERICAN
JOURNAL OF MEDICAL GENETICs, PART A 119A(3): 251-256