Post on 12-Apr-2017
PHARYNGEAL POUCHES
TONGUE, THYROID
Dr. G.Prabavathy
Assistant Professor
Pharyngea
l
apparatus
OBJECTIVES
Pharyngeal pouches – derivatives
Development of tongue
Development of thyroid
Pharyngeal arches
Pharyngeal clefts
Pharyngeal pouches
Pharyngeal membranes
PHARYNGEAL APPARATUS
Pharyngeal arch Nerves
First arch Maxillary and Mandibular
nerves
Chorda tympani nerve
Second arch Facial nerve
Third arch Glossopharyngeal nerve
Fourth arch Superior laryngeal branch
of vagus
Sixth arch Recurrent laryngeal branch
of vagus
DERIVATIVES OF PHARYNGEAL ARCHES
Nerves of the pharyngeal arches
MUSCLES OF PHARYNGEAL
ARCHES
Pharyngea
l arch
Muscles
First arch Muscles of Mastication (Temporalis,
Masseter, Medial and Lateral Pterygoid)
Anterior belly of digastric, Mylohyoid,
Tensor tympani & tensor veli palatini
Second arch Muscles of facial expression, posterior belly
of digastric, stylohyoid, stapedius
Third arch Stylopharyngeus
Fourth arch Cricothyroid, levator palati, contrictor of
pharynx and intrinsic muscles of larynx Sixth arch
SKELETAL ELEMENT OF PHARYNGEAL
ARCHES
Pharynge
al arch
Skeleton Ligaments
First arch
(Meckes’s
cartilage)
Malleus, and Incus
Premaxilla, maxilla
,zygomatic bone, part of
temporal bone, mandible,
Anterior ligament of
malleus
Sphenomandibular
ligament
Second arch
(Reichert’s cartilage)
Stapes, styloid process,
Smaller cornu of hyoid bone,
superior surface of body of the
hyoid bone
Stylohyoid ligament
Third arch Greater cornu and lower part
of body of hyoid bone
Fourth arch Laryngeal cartilages (thyroid,
cricoid, arytenoids,
corniculate, cuneiform) Sixth arch
PHARNYGEAL POUCHES
PHARNYGEAL POUCHES Four pairs of pouches – evaginations of endoderm,
lining between two arches
FIRST PHARYNGEAL POUCH
First pharyngeal pouch – tubotympanic recess
Distal part of tubotympanic recess – middle ear
cavity and mastoid antrum
Proximal part – eustachian/auditory tube
SECOND PHARYNGEAL POUCH • Endoderm proliferates to Form solid buds, central core
of these buds breaks down to form Tonsillar crypts
• Part of this pouch remains as intratonsillar crypt
(crypta magna)
THIRD PHARYNGEAL POUCH
Dorsal bulbar part – parathyroid III or inferior
parathyroid gland
Ventral tubular part - thymus
FOURTH PHARYNGEAL POUCH
Dorsal bulbar part – superior parathyroid gland IV
Fifth pouch incorporated with fourth pouch – caudal
pharyngeal complex – para follicular cells or c cells
SUMMARY
Pharyngeal arches – five in number, present in lateral wall and floor of the primitive pharynx
Pharyngeal clefts- four in number, present externally between the arches, lined by ectoderm
Pharyngeal pouches – four in number, present internally between the two pharyngeal arches, lined by the endoderm
Pharyngeal membranes – four in number and located between adjacent arches
TONGUE
THYROID GLAND
TONGUE
• Muscular organ located in the oral
cavity.
• Consists of connective tissue and
interlacing skeletal muscle fibres
• Covered by surface elevations
called papillae
i. Fungiform papillae
ii. Filliform papillae
iii. Circumvallate papillae
iv. Foliate papillae
TONGUE
Circumvallate
papillae
Filliform
Fungiform
Anterior 2/3rd
Posterior
1/3rd
Posterior
most part
V shaped
sulcus
terminalis
Tongue develops in the floor of developing mouth from
first, second, third and fourth pharyngeal arches
Tuberculum impar – small median swelling develops
cranial to foramen caecum
Lingual swelling – two lateral oval swellings on each
side of tuberculum impar
Hypobrachial eminence (Copula of His) – large
median swelling develops in relation to second, third
and fourth pharyngeal arches
DEVELOPMENT OF VARIOUS PARTS OF
TONGUE
Two lateral lingual swelling overgrow tuberculum impar and merge
with each other – anterior two- third of tongue
Cranial part of hypobrachial eminence – posterior one-third of
tongue including circumvallate papillae
Caudal part of hypobrachial eminence – posterior most part of the
tongue and epiglottis
GROWTH OF THIRD ARCH OVER SECOND ARCH
MUSCLES OF THE TONGUE
Develops from myoblasts that migrate into
developing tongue from occipital myotomes
CORRELATION OF NERVE SUPPLY OF TONGUE WITH ITS
DEVELOPMENT
SEPARATION OF TONGUE FROM FLOOR OF
MOUTH
Separation of tongue from the floor of the mouth
by deepening of linguogingival sulci
ANAMOLIES OF TONGUE
TONGUE TIE(Ankyloglossia)
Due to frenulum of tongue extends to the tip of the
tongue, thus preventing its protrusion and causing
difficulty in speech
BIFID TONGUE MACROGLOSSIA
CONGENITAL ANOMALIES
FISSURED TONGUE
THYROID GLAND
THYROID GLAND
• Highly vascular
endocrine gland
• Two lobes connected by
isthmus
Thyroid gland develop during third week of IUL as
endodermal thickening- diverticulum
thyroglossal duct
PATH OF THYROGLOSSAL DUCT
HISTOGENESIS OF THYROID GLAND
Parafollicular cells (C
cells) – neural crest of caudal
pharyngeal complex
I Anomalies of position of thyroid:
Lingual thyroid – 10%
Sublingual thyroid
Intrathoracic thyroid
II Ectopid thyroid:
Larynx
Trachea
Esophagus
Pericardium
Pleura
Ovaries
CONGENITAL ANOMALIES
Lingual thyroid
THYROGLOSSAL CYST:
May form anywhere along the course
of the Thyroglossal duct.
Persistense of a part of thyroglossal
duct turned into a cyst called
Thyroglossal Cyst.
always formed in the midline of the
front the Neck and observed by the age
of 5 years.
Cyst Ruptures-Fistula.
CONGENITAL ANOMALIES
PYRAMIDAL LOBE
ACCESSORY LOBE
1. parathyroid gland arises from
A) 1st and 2nd pharyngeal pouch
B) 3rd and 4th pharyngeal pouch
C) 5th and 6th pharyngeal arch
D) 3rd and 4th pharyngeal arch
2. nerve of III pharyngeal arch supplies
A)cricothyroid
B)stylopharyngeus
C)stapedius
D)stylohyoid
3.All the muscles of tongue are supplied by
A) Facial nerve
B) lingual nerve
C) Hypoglossal nerve
D) Occipital nerve
Enumerate the Derivatives of second pharyngeal
arch
Name the Derivatives of first pharyngeal arch
Development oy hyoid bone [apr 2002]
Explain Cervical sinus
Development of parathyroid [dec 2010]
Thyroglossal duct [dec 2011]
Explain the Development of thyroid gland
Brief account of Development of tongue