1. ANATOMY AND
EMBRYOLOGY OF THE
PHARYNX
DEPT OF
OTORHINOLARYNGOLOGY
J.J.M.M.C
DAVANGERE

2. EMBRYOLOGY
Components of
branchial/pharyngeal
apparatus:
1) Pharyngeal arches
2) Pharyngeal pouches
3) Pharyngeal
clefts/grooves

3. PHARYNGEAL (BRANCHIAL)
ARCHES
• Derived from neural crest cells
• Resemble fish gills (branchia)
• Begin to develop early in the 4th week
• By end of 4th week, four pairs of arches are
visible on the surface (not 5th and 6th ) and a
buccopharyngeal membrane ruptures forming
communication between primitive oral cavity and
foregut

4. PHARYNGEAL ARCHES
(CONT.)
• Contribute to the
formation of the neck as
well as the face.
• Visible structures at 42
weeks:
1st arch: mandibular
prominence, maxillary
prominences, and the
frontonasal prominence

5. PHARYNGEAL ARCHES
(CONT.)
• Core of mesenchymal
tissue covered by surface
ectoderm (outside) and
by endodermal epithelium
(inside)
• Ectoderm -> skeletal
• Mesoderm -> muscles
with accompanying nerve
• Arterial component (aortic
arches)
• Therefore, each arch
carries nerve, muscle,
bone and blood supply

6. FIRST PHARYNGEAL ARCH
• Maxillary process (dorsal)
– Premaxilla, maxilla, zygomatic bone, portion
of temporal bone
• Mandibular process (ventral)
– Contains Meckel’s cartilage which disappears
except for dorsal end (incus & malleus)
and mandible

7. FIRST PHARYNGEAL ARCH
• Muscles of mastication, digastric (ant
belly), mylohyoid, tensor tympani and
tensor palatini
• Therefore, the accompanying motor nerve
is the mandibular branch of trigeminal (V2)
and sensory are V1, V2, and V3
• 1st aortic arch practically disappears but
forms the maxillary artery

8. SECOND PHARYNGEAL ARCH
• Reichert’s cartilage – stapes, styloid process,
stylohyoid ligament, lesser horn and upper part
of the hyoid
• Muscles include: stapedius, stylohyoid, digastric
(post belly), auricular, and those of facial
expression
• Facial nerve (CN VII)
• 2nd aortic arch – stapedial & hyoid arteries

9. THIRD PHARYNGEAL ARCH
• Cartilaginous contributions include greater horn
and lower part of hyoid
• Sole muscle: stylopharyngeus
• CN IX (Glossopharyngeal nerve)
• 3rd aortic arch (quite large): common carotid, 1st
portion of internal carotid (remainder dorsal
aorta), and external carotid

10. FOURTH & SIXTH PHARYNGEAL
ARCH
• Cartilaginous contributions to larynx derived from fusion:
thyroid, cricoid, arytenoid, corniculate, and cuneiform
• Muscles of 4th: cricothyroid, levator palatini, and
pharyngeal constrictors are innervated by SLN (CN X)
• Muscles of 6th: intrinsics of larynx are innervated by RLN
(CN X)
• 4th aortic arch: L->arch of aorta & R->subclavian
• 6th aortic arch: L & R pulmonary with ductus arteriosus on
left

11. ANATOMY OF THE PHARYNX
1. EPIGLOTTIS
2. HYOID BONE
3. ARYEPIGLOTTIC FOLD
4. VOCAL FOLD
5. THYROID CARTILAGE
6. CRICOID CARTILAGE
7. OESOPHAGUS
8. THYROID ISTHEMUS
9. NASOPHARYNGEAL TONSIL
10. EUSTACHIAN TUBE
11. SALPHINGOPHARYNGEAL
FOLD
12. NASOPHARYNX
13. PALATOGLOSSAL FOLD
14. PALATINE TONSIL
15. OROPHARYNX
16. PALATOPHARYNGEAL FOLD
17. HYPOPHARYNX

12. ANATOMY (CONT…)
• It is a conical fibromuscular tube forming upper
part of air and food passage. It is 12-14 cm long.
Extends from base of skull to inferior border of
cricoid cartilage anteriorly and inferior border of
C6 posteriorly
• Widest portion (5cm) at hyoid
• Narrowest portion (1.5cm) at caudal end
• Divided into 3 parts: nasopharynx, oropharynx,
and laryngo(hypo)pharynx

13. NASOPHARYNX/
EPIPHARYNX
• Anterior: choana (posterior nasal aperture)
• Posterior: pharyngobasilar membrane, superior
constrictor muscle, arch of atlas covered by
prevertebral muscle and fascia.
• Superior: basi-occiput and basi-sphenoid.
• Inferior: soft palate (Anteriorly) deficient
posteriorly-nasopharyngeal isthmus.
• Lateral :pharyngeal opening of eustachian tube
situated 1.25 cm behind the posterior end of
inferior turbinate, bounded by torus tubaris.
above and behind the tubal elevation is a
recess- fossa of Rosenmuller.

14. NASOPHARYNX/
EPIPHARYNX

15. STRUCTURES OF PHARYNGEAL
WALL
1. Mucus membrane-ciliated columnar in
nasopharyx and stratified squamous in other
areas.
2. Pharyngeal aponeurosis ( pharyngo-basilar
fascia)
3. Muscular coat-external layer contains
superior , middle, inferior constrictors. Internal
layer-stylopharyngeus, salpingopharyngeus,
palatoparyngeus.
4. Buccopharyngeal fascia.

16. KILLIAN’S DEHISCENCE
• Inferior constrictor muscle has two parts
-thyropharyngeus with oblique fibres and
cricopharyngeus with transverse fibres. A
potential gap between these two parts is
called killian’s dehiscence. Also called
“gateway of tears” as perforation can
occur during esophagoscopy. This is also
the site of mucosal herniation in case of
pharyngeal pouch.

17. NASOPHARYNGEAL TONSIL
• Tonsil - It is a sub epithelial collection of
lymphoid tissue at the junction of roof and
posterior wall of nasopharynx. it increases in
size up to 6 yrs and then gradually atrophies.
• Bursa - epithelial lined median recess found
within the adenoid mass and extends from
pharyngeal mucosa to periosteum of
basiocciput. It represents attachment of
notochord to the pharyngeal endoderm during
embryonic life. Sometimes an abscess can form
in the bursa -Thornwald’s disease.

18. TUBAL TONSIL AND SINUS OF
MORGAGNI
• Tubal tonsil-Collection of subepithelial
lymphoid tissue situated at the tubal
elevation. It is continuous with
nasopharyngeal tonsil forms a part of
waldeyar’s ring.
• Sinus of Morgagni - space between the
base of the skull and free upper border of
superior constrictor muscle. Eustachian
tube, levator veli palatine, tensor veli
palatine and ascending pharyngeal artery
passes through it.

19. PASSAVANT’S RIDGE
• It is a mucosal ridge raised by fibres of
palato-pharyngeus. It encircles the
posterior and lateral walls of
nasopharyngeal isthmus. Soft palate
during contraction, makes firm contact
with this ridge to cut off nasopharynx from
the oropharynx during deglutition or
speech.

20. WALDEYER’S RING
• Scattered subepithelial lymphoid aggregates in
and around pharynx are collectively called
waldeyer’s ring
• It consists of inner ring and outer ring
• Inner ring: nasopharyngeal tonsil, palatine tonsil,
lingual tonsil, tubal tonsil, lateral pharyngeal
bands, nodules in posterior pharyngeal wall
• Outer ring: lymph nodes at retropharyngeal,
styloid, lateral pharyngeal, behind
sternomastoid, at bifurcation of common carotid,
in front of sternomastoid, at angle of jaw, at
hyoid and subhyoid

21. WALDEYER’S RING

22. FUNCTIONS OF
NASOPHARYNX
1. Conduit for air.
2. Ventilation of middle ear and equalize
pressure.
3. With passavant’s ridge to cut off
nasopharynx from oropharynx.
4. Resonating chamber during voice
production.
5. Drainage channel for secretion drainage
from nose.

23. OROPHARYNX
• Extends from plane of hard palate above to
plane of hyoid bone below.
• Anterior: oropharynx communicates with oral
cavity,
• Posterior: related to retropharyngeal space
opposite C2-3, superior constrictor through
oropharyngeal isthmus.
• Superior: soft palate
• Inferior: base of tongue, lingual tonsils,
valleculae, superior epiglottis.
• Laterally: palatoglossal (Anteriorly) and
palatopharyngeal arches (posteriorly), palatine
(faucial) tonsil

24. OROPHARYNX

25. FUNCTIONS OF OROPHARYNX
1. Conduit for passage of food and air.
2. Pharyngeal phase of deglutition.
3. Vocal tract for certain speech sounds.
4. Appreciation of taste.
5. Local defense and immunity.

27. HYPOPHARYNX
• Lowest part of larynx, Lies posterior and partly
on sides of the larynx. lies opposite C3-6
• Superior: superior border of epiglottis and
pharyngoepiglottic folds (plane passing through
body of hyoid bone)
• Inferior: inferior border of the cricoid
• Posterior/lateral: middle & inferior constrictors,
bodies of C3-C6
• Anterior: laryngeal inlet
• Subdivided into three regions-pyriform sinus
(fossa), post cricoid region, posterior pharyngeal
wall.

28. PYRIFORM SINUS
• Lies on either side of larynx and extends from
pharyngoepiglottic fold to the upper end of
esophagus.
• boundaries:
-laterally: thyrohyoid membrane and thyroid
cartilage.
-medially: aryepiglottic fold, posterolateral
surface of arytenoid, cricoid cartilage.
• Internal laryngeal nerve passes submucosally in
lateral wall of sinus so easily accessible for local
anaesthesia. In carcinoma of pyriform sinus this
nerve causes referred otalgia.

29. PHARYNGEAL MUSCLES

30. PHARYNGEAL MUSCLES AND
NERVE SUPPLY.
• External circular and internal longitudinal
(opposite in remainder of GI tract)
• External: 3 constrictors (CN XI via X and
ELN/RLN for middle and inferior) function to
constrict wall of pharynx during swallow
• Internal: palatopharyngeus and
salpingopharyngeus (CN XI via X) and
stylopharyngeus (CN IX) act to elevate pharynx
and larynx during speech/swallow
• CN V supplies nasopharynx

31. PHARYNGEAL
MUSCLES(CONT…)
• Tensor veli palatini (V3) tenses soft palate
& opens ET during yawn/swallow
• Levator veli palatini (CN XI via X) elevates
palate during swallow/yawn
• Palatoglossus (CN XI via X) approximates
tongue and soft palate

32. PHARYNGEAL MUSCLES

33. PHARYNGEAL LYMPHATIC
DRAINAGE
• Oral cavity
– Submandibular, upper
deep cervical
• Oro/hypopharynx
– Upper deep cervical,
retropharyngeal,
parapharyngeal, posterior
cervical
• Nasopharynx
– Upper deep cervical either
directly or indirectly through
retropharyngeal and
parapharyngeal LN

34. PHARYNGEAL VESSELS

35. BLOOD SUPPLY
• Blood supply is by branches of external
carotid artery
1. Ascending pharyngeal. A
2. Ascending palatine branch of facial. A
3. Lingual. A
4. Superior thyroid. A

36. VENOUS DRAINAGE
• The veins form the pharyngeal plexus
which drains into common facial vein and
internal jugular vein

37. PARAPHARYNGEAL SPACE
• Pyramidal in shape with its base at the base of
skull and apex at the hyoid bone
• Boundaries:
a) Superior: base of skull
b) Inferior: mediastinum
c) Medial: buccopharyngeal fascia, prevertebral
muscle and fascia
d) Lateral: ramus of mandible, deep surface of
parotid, medial pterygoid muscle
• Contents: carotid artery, jugular vein, CN ix, x,
xi, xii, cervical sympathetic trunk, deep cervical
lymph nodes

38. PARAPHARYNGEAL SPACE

39. RETROPHARYNGEAL SPACE
(GILLETTE’S SPACE)
• Space lies behind the pharynx, divided by a
median partition into right and left
compartment
• Boundaries:
a) Anteriorly: buccopharyngeal fascia
b) Posteriorly: prevertebral fascia
c) Superior extent: base of skull
d) Inferior: bifurcation of trachea
• Contents: retropharyngeal lymph nodes which
usually disappear at 3-4 years of age.