Anatomy of pharynx

1. ANATOMY OF PHARYNX
 Dr.Jiten Lad
 First Year Resident
 Dr.M.K.Shah Medical
College

2. PHARYNX
◆It is a musculo fascial half-cylinder that
links the oral and nasal cavities in the head
to the larynx and esophagus in the neck. It
is 12–14 cm long.
◆It is attached above to the base of skull and
continuous below, approximately at the
level of the sixth cervical vertebra, with
esophagus.

3. ◆The width of pharynx is 3.5 cm at its base
and this narrows to 1.5 cm at pharyngo-
oesophageal junction, which is the
narrowest part of digestive tract apart from
the appendix.
◆The pharyngeal cavity is a common
pathway for ‘air ’and ‘food’. (common
passages of respiratory systems and
digestive systems)

5. BOUNDARIES
● Superiorly-Base of skull including
posterior part of body of sphenoid and
the basilar part of the occipital bone.
● Inferiorly-pharynx continues with
esophagus at the level of 6th cervical
vertebra/ lower border of cricoid
cartilage.
● Posteriorly-Prevertebral fascia separating
it from cervical spine

6. ● Anteriorly-Communication with Nasal
cavity, Oral cavity, and Larynx.
o ON EACH SIDE-
i) It is attached to the:
 Medial pterygoid
plate
 Pterygo
mandibular raphe
 Mandible

7.  Tongue
 Hyoid bone
 Thyroid and cricoid cartilages
ii) Communication with middle ear via
Eustachian tube
iii) Styloid process and muscles attached to it
iv) Common, Internal and External Carotid
Artery

8. DIVISIONS OF PHARYNX

9. DIVISIONS OF PHARYNX

10. DIVISIONS OF PHARYNX
1. NASOPHARYNX/ EPIPHARYNX
From the base of skull above to the level
of soft palate/ palatal sphincter (C2 level).
2. OROPHARYNX
From palatal sphincter to the level of tip
of epiglottis (C4 level).
3. LARYNGOPHARYNX/HYPOPHARYNX
From tip of epiglottis to the lower border
of cricoid cartilage (lower border of C6).

11. STRUCTURE OF PHARYNX
From within outwards it consists of four layers:
1. Mucousmembrane- It is ciliated columnar in
the nasopharynx and stratified squamous
elsewhere.
2. Pharyngealaponeurosis/Pharyngobasilar
fascia-it is a fibrous layer lining the muscular
coat.It is thick between superior border of
superior constrictor muscle and base of skull and
becomes thin inferiorly

12. 1. Muscularcoat-consist of-
 Outer Circular Layer:consist of 3 muscles-
 >Superiorconstrictor >Middle constrictor >Inferior
constrictor
 Inner Longitudinal Layer consist of 3 muscles-
>Stylopharyngeus >Salpingopharyngeus
>Palatopharyngeus
4. Buccopharyngeal fascia-covers the outer surface of
constrictor muscles and in the upper part, prolonged
forwards to cover the buccinator muscles.

13. STRUCTURE OF PHARYNX
Base of
skull
Eustachian tube
Mucous membrane
Sub mucosa
Pharyngobasilar fascia
Muscular coat
Buccopharyngeal fascia
Superior Constrictor
Venous Plexus
Middle Constrictor
Inferior
Constrictor
Sinus
of
Morgagni

14. PHARYNGEAL WALL

15. PHARYNGEAL WALL
Muscle Posterior
Attachment
Anterior
Attachment
Innervation Function
Superior
Constrictor
Pharyngeal
raphe
Pterygomandibular raphe and
adjacent bone on the mandibular
and pterygoid hamulus
Vagus
Nerve
Constriction
of pharynx
★Constrictor muscles:
Middle
Constrictor
Pharyngeal
raphe
Upper margin of greater horn of hyoid
bone and adjacent margins of lesser
horn and stylohyoid ligament
Vagus
Nerve
Constriction
of pharynx
Inferior
Constrictor
Pharyngeal
raphe
Cricoid cartilage, oblique line of
thyroid cartilage, and a ligament that
spans between these attachments and
crosses the cricothyroid muscle
Vagus
Nerve
Constriction
of pharynx

16. 26

17. PHARYNGEAL WALL
Muscle Origin Insertion Innervation Function
Stylopharyngeus Middle side of base
of styloid process
Pharyngeal wall Glossopharyngea
l nerve [Ⅸ]
Elevation of the
pharynx
Salpingo
pharyngeus
Inferior aspect of
pharyngeal end of
pharyngo-tympanic
tube
Pharyngeal wall Vagus nerve
[Ⅹ]
Elevation of
pharynx
Palatopharyngeus Upper surface of
palatine aponeurosis
Pharyngeal wall Vagus nerve
[Ⅹ]
Elevation of phary-
nx, and closure of
the oropharyngeal
isthmus
★Longitudinal muscles:

18. 15

19. FASCIA
• The pharyngeal fascia is separated into
two layers:
Buccopharyngeal Fascia: a thin layer, coats
the outside of the muscular part of the
wall.
Pharyngobasilar Fascia: a much thicker
layer, lines the inner surface

20. PHARYNGEAL SPACES
There are two potential spaces in
relation to the pharynx where
abscesses can form.
1. Retropharyngeal space, situated
behind the pharynx.
2. Parapharyngeal space, situated on the
side of pharynx.

21. RETROPHARYNGEAL SPACE
• Between the buccopharyngeal fascia and
prevertebral fascia, which extends from
skull base to the upper part of posterior
mediastinum (T1,T2), the bifurcation of
trachea.
• Anteriorly by the posterior
pharyngeal wall and
buccopharyngeal fascia.

22. • Posteriorly by the cervical vertebra their
muscles and fascia.
• One on each side, and separated from
parapharyngeal space.
• It contains retropharyngeal lymph nodes and
connective tissue.

24. RETROPHARYNGEAL SPACE

25. RETROPHARYNGEAL SPACE ABCESS
ACUTE:
SOURCE OF INFECTION:
• Infection in adenoids, nasopharynx , posterior nasal
sinuses or nasal cavity
• Penetrating injury of posterior pharyngeal wall or cervical
esophagus
• Patrositis due to acute mastoiditis
CLINICAL FEATURES:
• Unilateral bulging in posterior pharyngeal wall on one side
of midline
• Dysphagia

26. • Air way obstruction
• Croupy cough
• Stiff neck and extended head ( Torticollis)
CHRONIC:
SOURCE OF INFECTION:
• Tuberculosis of cervical spine ( Pot’s Spine)
• Tuberculosis of retropharyngeal lymph nodes
• Hematogenous seeding: S.aureus are common

27. CLINICAL FEATURES:
• Mild discomfort in throat and Dysphagia
• Fluctuant swelling in posterior pharyngeal wall centrally
or on one side of midline
• Cervical tuberculous lymph nodes
Treatment:
Medical-systemic intravenous antibioticsin acute & full
course of multidrug anti tubercular therapy in chronic
abscess
IncisionandDrainage-vertical incision is made over the most
fluctuant area of abscess and suction is kept ready to prevent
aspiration of pus
Tracheostomy – in large abscess causing respiratory distress
and laryngeal oedema.

28. PARAPHARYNGEAL SPACE
• Situated on the side of pharynx.
• It is an inverted cone-shaped potential
space that extends from the hyoid bone
to the base of the skull.
• It’s occupied by the carotid vessels,
Internal jugular vein, Deep cervical
lymph nodes , The last four cranial
nerves and Cervical sympathetic
trunk.

29. • Invertedpyramid with floorat
skullbase,tipathyoid, bounded
bythepharyngealwall
medially andthemandible
laterally
• Alsoknown as-lateral
pharyngealspace,
pharyngomaxillaryspace,
pterygomaxillaryspace,
pterygopharyngealspace.

30. BOUNDARIES:
Superior: base ofskull.
Inferior: greater cornu of the hyoid bone.
Medial: middle layerof the deep cervical
fascia covering
the superiorpharyngeal constrictor
Levator veli palitini
tensor veli palatini

31. lateral: superficial layer of the deep cervicalfascia
extending between styloid
process and mandibular ramus,1
anterior:pterygomandibularraphe and superficial
layer of the deepcervical
fascia covering the medialpterygoid muscle
posterior: an extension of tensor veli palatini muscle
fascia termed thetensor-vascular-styloidfascia

32. COMPARTMENTS
• aponeurosis of Zuckerkandl and Testut This fascia joining
the styloid processto the tensor veli palatini

33.  PRE-STYLOID
COMPARTMENT
• Fat
• Retromandibularparotid
• Lymphnode
• Internalmaxillaryartery
• Inferior alveolarnerve
• Lingualnerve
 POST-STYLOID
COMPARTMENT
• Internalcarotidartery
• Jugularvein
• Sympatheticchain
• Cranialnerves ⅸ-ⅻ
• Lymphnodes

34. PARAPHARYNGEAL SPACE ABSCESS
SOURCES OF INFECTIONS:
• Oropharynx: Bursting of peritonsillar abscess, pharyngitis,
tonsillitisand adenoiditis
• Dental: Infections of usually lower last molars.
• Suppurative otitis mediacomplications:Bezold’s abscess
and petrositis.
• Extensions: Infections of parotid, retropharyngeal and
submaxillary spaces.
• Injuries:Penetrating injuries of neck.
• Iatrogenic: Injectionlocal anesthetic for tonsillectomyor
mandibular nerve block.

35. Common features:
The patients with parapharyngeal abscess usually
present with
• Fever
• Odynophagia
• Sore throat
• Torticollis (due to spasm of prevertebral muscles)
• Toxemia
• Anterior compartment:
• Prolapse of tonsil and tonsillar fossa
• Trismus due to spasm of medial pterygoid muscle
• Swelling behind the angle of jaw
• Odynophagia.

36. Posterior compartment:
• Pharyngeal bulging behind the posterior pillar.
• Cranial nerve palsies: CN 9, 10, 11 and 12 palsies will
present with dysphagia and
• hoarseness of voice, and ipsilateral nasal
regurgitationand ipsilateral palsies of palate,
• larynx and tongue
• Horner’s syndrome due to the involvement of
sympathetic chain. The syndrome consists of
ipsilateral: – Anhidrosis – Partial ptosis –
Enophthalmos – Constricted pupil
• Swelling in parotid region.

37. TREATMENT:
• Medical: Intravenous antibiotics to combat infection.
• Surgical drainage under general anaesthesia:
Preoperative tracheostomyis required in cases of
marked trismus or airway obstruction.

38. KILLIAN’S DEHISCENCE
• Inferior constrictor muscle has two parts:
Thyropharyngeus with oblique fibres and
Cricopharyngeus with transverse fibres.
• Between these two parts exists a potential
gap called Killian’s dehiscence.
• It is also called “gateway of tears” as perforation
can occur at this site during oesophagoscopy.
• This is also the site for herniation of
pharyngeal mucosa in cases of pharyngeal
pouch- zenker’s diverticulum.

39. KILLIAN’S DEHISCENCE

40. WALDEYER’S RING
• Scattered throughout the pharynx in its subepithelial
layer is the lymphoid tissue which is aggregated at places
to form masses, collectively called Waldeyer’s ring.
• It has no afferents and efferents drain into cervical
lymph nodes.
• The masses are:
1. Nasopharyngeal tonsil or the adenoids
2. Palatine tonsils or simply the tonsils
3. Lingual tonsil
4. Tubal tonsils (in fossa of Rosenmüller)
5. Lateral pharyngeal bands
6. Nodules (in posterior pharyngeal wall).

41. WALDEYER’S RING

42. LYMPHATIC DRAINAGE
• Nasopharyngeal tonsil and some
drainage from tubal tonsil is to
Retropharyngeal nodes
• Oropharynx- Into Upper Jugular chain
particularly Jugulodigastric (tonsillar)
node.
• Soft palate, Lateral and Posterior
pharyngeal walls and base of tongue- into
retropharyngeal and parapharyngeal
nodes.

43. LYMPHATIC DRAINAGE

44. BLOOD SUPPLY OF PHARYNX
• Ascending pharyngeal branch of external carotid
• Ascending palatine branch of facial (branch
of external carotid)
• Greater palatine branch of maxillary.
• Venous drainage through plexus which drains
to: superiorly : pterygoid plexus in the
Infratemporal fossa.
inferiorly : the facial and internal
jugular veins

45. NERVE SUPPLY OF PHARYNX
Nerve supply is by pharyngeal plexus of
nerves, which is formed by:
• Branch of vagus (X nerve): Motor supply
• Branches of glossopharyngeal (IX
nerve): Sensory supply
• Sympathetic plexus.

46. FUNCTIONS OF PHARYNX
• Pharynx helps to provide immunity and
formation of antibodies
• It protects the lower respiratory tract
• It forms plasma cells and lymphocytes
• Acts as a warning to the body against
infectious agents in air and food.

47. DIVISIONS OF PHARYNX

48. NASOPHARYNX (EPIPHARYNX)
• Nasopharynx is the uppermost part of the
pharynx and therefore, also called epipharynx.
• It is also called third chamber of nose, which
lies behind the nose and above the soft palate.
• Dimensions of nasopharynx are: 4 cm (height) × 4
cm (width) × 3 cm (length).
• Roofand posteriorwall form a continuous
sloping surface, which is formed mainly by the
basilar part of occipital bone and to some extent,
by body of sphenoid and arch of altas vertebra

49. • Floor is formed by the soft palate anteriorly
but is deficient posteriorly. It is through this
space, the nasopharyngeal isthmus, that the
nasopharynx communicates with the
oropharynx.
• Anterior wall is formed by posterior nasal
apertures or choanae, separated from each
other by the posterior border of the nasal
septum. Posterior ends of nasal turbinates
and meatuses are seen in this wall.

50. • Lateral wall has the eustachian tube opening, 1
to 1.25 cm (equidistant from all walls), behind
and little below the posterior end of inferior
turbinate.
• The opening is triangular in shape,
bounded above and behind by tubal
cartilage.
• Two folds of mucous membrane—
salpingopharyngeal and salpingopalatine
stretch from the opening of eustachian tube
to the walls of pharynx and palate.

51. • Torus tubarius is a mucosal elevation in
the lateral aspect of the nasopharynx,
formed by the underlying pharyngeal end
of the cartilaginous portion of the
Eustachian tube.
• The opening of the Eustachian tube
is anterior to the torus tobarius.
• Above and behind the tubal elevation is a
recess called fossa of Rosenmüller, which is
the commonest site for origin of carcinoma.

52. FOSSA OF ROSENMÜLLER

53. • Rathke’s pouch is seen as a dimple in
the roof of nasopharynx.
• It is reminiscent of the buccal mucosal
invagination, to form the anterior lobe of
pituitary.
• A craniopharyngioma may arise from it.

54. RATHKE’S
POUCH

55. • Sinus of Morgagni: It is an interval
between upper border of superior
constrictor and base of skull
and many structures pass upward from
the pharynx.
Structures passing through this
gap-
-Levator veli palatini
-Ascending palatine artery
-Tensor veli palatini
-Eustachian tube

56. • Passavant ridge is an elevation formed by
fibers of superior constrictor and
palatopharyngeus, which helps in closing the
nasopharynx from oropharynx with the
posterior border of soft palate. It encircles the
posterior and lateral walls of nasopharyngeal
isthmus

57. NASOPHARYNGEAL TONSIL (ADENOIDS)
• It is a subepithelial collection of lymphoid tissue at
the junction of roof and posterior wall of
nasopharynx.
• It causes the overlying mucous membrane to be
thrown into radiating folds.
• It increases in size up to the age of 6 years and then
gradually atrophies by age of 11-12 years.
• No feeding blood vessel, supplied by adjacentplexus
only.
• It has no capsule.

58. NASOPHARYNGEAL BURSA
• It is an epithelial-lined median recess
found within the adenoid mass.
• It extends from pharyngeal mucosa to
the periosteum of the basiocciput.
• It represents the attachment of notochord to
the pharyngeal endoderm during embryonic
life.
• When infected, it may be the cause of
persistent postnasal discharge or crusting.
• Sometimes an abscess can form in the

59. FUNCTIONS OF NASOPHARYNX
1. Acts as a conduit for air, which has been warmed,
humidified in the nose, towards its passage to the
larynx and trachea.
2. Through the eustachiantube, it ventilates the middle
ear and equalizes air pressure on both sides of
tympanic membrane.
3. Elevation of the soft palate against posterior
pharyngeal wall and the Passavant’s ridge helps to
cut off nasopharynx from oropharynx. This function
is important during swallowing, vomiting, gagging
and speech.

60. 1. Acts as a resonating chamber during voice
production. Voice disorders are seen in
nasopharyngeal obstruction and
velopharyngeal incompetence
2. Acts as a drainage channel for the mucus
secreted by nasal and nasopharyngeal
glands.

61. OROPHARYN
X

62. OROPHARYN
X

63. OROPHARYN
X

64. OROPHARYNX
Anteriorwall:
• upper part- deficient, communicates with oral cavity
through Oropharyngeal isthmus/ Isthmus of Fauces.
• lower part - Base of tongue
- Lingual tonsils
- Valleculae
• Oropharyngeal isthmus: It is bounded by following
structures:
i. Above: Soft palate
ii. Inferior: Dorsal surface of tongue
iii. Lateral: On either side, by palatoglossal arch
(anterior tonsillarpillar)

65. OROPHARYNX
• Base of tongue: It lies posterior to circumvallate
papillae and insertion of palatoglossal muscle.
• Lingual tonsils: They are situated in the base of tongue.
• Valleculae: These cup-shaped spaces, one on each side,
lie between the base of tongue and anterior surface of
epiglottis.
• The median glossoepiglottic fold separates the
two valleculae.
• Laterally they are bounded by the pharyngoepiglottic
fold that is the upper limit of pyriform sinus of
laryngopharynx.

66. OROPHARYNX
• Posteriorwall:
Body of second cervical and upper part of 3rd
cervical vertebra.
• Lateral wall:
- Palatine/Faucial tonsil
- Anterior pillar (Palatoglossus muscle)
- Posterior pillar(Palatopharyngeus muscle)
Both anterior and posterior pillars diverge from the
soft palate and enclose a triangular depression called
tonsillar fossa in which is situated the palatine tonsil

67. OROPHARYNX
• Superior:
Anteriorly soft palate makes the roof of
oropharynx.
Posteriorly it communicates with nasopharynx
through nasopharyngeal isthmus at the
plane of hard palate and atlas vertebra.
• Inferior:
It communicates with laryngopharynx at
the plane of upper border of epiglottis and
the pharyngoepiglottic folds and third
cervical vertebra.

68. OROPHARYNX
Lymphatic Drainage:
• Upper jugular chain particularly the
jugulodigastric (tonsillar) node. „
• The soft palate,lateral and posterior pharyngeal
walls and the base of tongue also drain into
retropharyngealand parapharyngeal nodes and
from there to the jugulodigastric and posterior
cervical group.
• The base of tongue may drain bilaterally

69. Functions of Oropharynx:
• A common conduit for the passage of both
air and food.
• Oropharyngeal phase of deglutition.
• Vocal tract for certain speech sounds.
• Taste: The base of tongue, soft palate,
anterior pillars and posterior pharyngeal
wall contain taste buds.
• Local defence and immunity.

70. PALATINE (FAUCIAL) TONSILS
• These are two masses of lymphoid tissue situated in the
lateral wall of oropharynx.
• Each tonsil is placed between palatoglossal (anteriorpillar)
and palatopharyngeal fold (posterior pillar).
• Its medial surface is free and projects into the pharynx.
• Inferiorly, it extends into dorsum of tongue.
• Superiorly, it invades the soft palate.
• Plica triangularis is a free fold of mucous membrane
extending from palatoglossal archto the anteroinferior
part of tonsil.

71. • Upper part of tonsil contains a deep cleft called
crypta magna or intratonsillar cleft.
• Medial surface presents 12 to 15 orifices termed
tonsillar crypts or pits, which extend into the whole
substance of tonsil, branching inside the tonsil.
These help in increasing the surface area.

72. • Lateral surface is covered by fibrous capsule separated
from muscular wall formed by superior constrictor with
styloglossus muscle on its lateral side.
• At antero inferior part, the capsule is firmly attached in the
side of tongue.
• Tonsillar branch of facial artery with two veins enters the
tonsil at this point.
• Paratonsillar veins descend from the soft palate onto the
lateral aspect of capsule of tonsil and it is this vessel, which
is responsible for massive bleeding, if injured during
operation.
• Internal carotid artery lies 2.5 cm behind and lateral to the
tonsil.

73. PALATINE (FAUCIAL) TONSILS
• The tonsillolingual sulcus, which separates the tonsil
from tongue, is a common site for carcinoma.
• Supratonsillar fossa: The medial surface of tonsillar
upper pole has a semi-lunar fold, which extends
between anterior and posterior pillars. This pole
encloses a potential space called supratonsillar fossa.
• Anterior tonsillar space: At the lower pole, which is
attached to the tongue, a triangular fold of mucous
membrane extendsfrom anterior pillar to the
anteroinferior part of tonsil and encloses a space called
anterior tonsillar space.

74. TonsillarCrypts:
• The nonkeratinizing stratified squamous epithelium on
medial surface of tonsil dips into the tonsillar mass and
forms crypts (12–15).
• Openings of crypts can be seen on the medial surface of
the tonsil.„
• Crypta magna or intratonsillarcleft: It is situated near the
upper part of tonsil. It is very large and deep and represents
the ventral part of second pharyngeal pouch.
• Secondary crypts: They arise from the main crypts within
the substance of tonsil.„
• Content:Crypts may be filled with cheesy material, which
consists of epithelial cells, bacteria and food debris and can
be expressed out with pressure over the anterior tonsillar
pillar.

75. Capsule:
• Lateral surface of tonsil is covered by a well-
defined fibrous capsule, which is separated
from the bed of tonsil by loose areolar tissue
that allows easy dissection in this plane during
tonsillectomy.
• In this same plane occurs the
peritonsillar abscess.
• Some fibers of palatoglossus and
palatopharyngeus muscles are attached to
tonsillar capsule.

76. PALATINE (FAUCIAL) TONSILS
Blood Supply:
• Arterial supply: The main artery of tonsil is
tonsillar branch of facial artery, which arises
from external carotid artery.
• The other vessels, which supply the tonsil include:
-Ascending pharyngeal artery from external carotid.
-Ascending palatine, a branch of facial artery.
-Dorsal lingual branch of lingual artery.
-Descending palatine branch of maxillary artery.

77. PALATINE (FAUCIAL) TONSILS
Blood Supply:
• The ascending pharyngeal, facial, lingual and
maxillary arteries are all branches of external
carotid artery that may need to be ligated in cases
of refractory bleeding after tonsillectomy.
• Venous drainage: Veins from the tonsils drain into
paratonsillar veins, which are present on lateral
surface of tonsil and drain into the common facial
vein and pharyngeal venous plexus.

78. BLOOD SUPPLY OF TONSIL

79. PALATINE (FAUCIAL) TONSILS
Nerve Supply:
• Lesser palatine branches from
sphenopalatine ganglion of maxillary
division of trigeminal nerve (CN V2).
• Glossopharyngeal nerve (CN IX).

80. BED OF TONSIL

81. • The pharyngobasilar fascia, superior constrictor,
buccopharyngeal fascia, glossopharyngeal nerve
and styloglossus muscle form the bed of tonsil.
• Lateral to the superior constrictor muscles lies facial
artery, submandibular salivary gland, posterior
belly of digastric muscle, medial pterygoid muscle
and the angle of mandible.
• Styloid process: The styloid process when
enlarged may be palpated intraorally in the lower
part of tonsillar fossa. The glossopharyngeal
nerve and styloid process can be approached
through the tonsil bed after tonsillectomy.

82. HYPOPHARYNX
• Hypopharynx extends from the tip of epiglottis
or plane of hyoid bone to the lower border of
cricoid cartilage, from 3rd to 6th cervical
vertebrae.
• Clinically, it is subdivided into three
regions: Pyriform sinus,
Post cricoid region and
Posterior pharyngeal
wall.

83. HYPOPHARYNX

84. HYPOPHARYNX
• Inferior: It becomes continuous with esophagus at
the level of lower border of cricoid cartilage and
6th cervical vertebra.
• Anterior: It communicates with larynx through
the laryngeal inlet, which is bounded by the
epiglottis, aryepiglottic folds and arytenoids.
• Inlet of larynx:
i. Posterior surface of arytenoid cartilage
ii. Posterior aspect of cricoid cartilage.
• Pyriform sinus lies on each side of laryngeal orifice.

85. HYPOPHARYNX
Pyriform sinus (Fossa):
• Each pyriform fossa, which lies on either side of the larynx,
forms the lateral channel for food.
• Foreign bodies may lodge in the pyriform fossa.
• Boundaries:
Lateral: Thyrohyoid membrane and the thyroid
cartilage.
Medial: Aryepiglottic fold, posterolateral surface
of arytenoid and cricoid cartilages.
Superior: Pharyngoepiglottic fold separates it
from vallecula.
Inferior: It opens into the esophagus at the level
of lower border of cricoid cartilage.

86. HYPOPHARYNX
Pyriform sinus (Fossa):
• Internal laryngeal nerve runs submucosally in
the lateral wall of the sinus and thus is easily
accessible for local anaesthesia.
• It is also through this nerve that pain is referred
to the ear in carcinoma of the pyriform sinus.
• It is most richly supplied by lymphatics, which
come out of thyrohyoid membrane to end in
upper deep cervical group of lymph nodes.

87. HYPOPHARYNX
Post cricoid region:
• This anterior wall of laryngopharynx
(pharyngoesophageal junction) extends
between the level of arytenoids and lower
border of cricoid lamina.
• Post cricoid region is a common site for
carcinoma, which usually develops from
Plummer-Vinson syndrome especially in
females.
• The sensory supply is the internal laryngeal nerve,
a branch of the superior laryngeal nerve

88. HYPOPHARYNX
Post cricoid region:
• A rich venous plexus in this region drains
into superior laryngeal veins.
• It is more prominent in infants and
engorges during crying, known as the
"postcricoid cushion" on laryngoscopy,
perhaps as protection against emesis.

89. HYPOPHARYNX
Posterior pharyngeal wall:
• Posterior pharyngeal wall extends from hyoid
bone to the cricoarytenoid joint, between the
apices of pyriform fosse.

90. FUNCTIONS OF HYPOPHARYNX
• Common pathway for air and food.
• Provides a vocal tract for resonance of certain
speech sounds. „
• Helps in deglutition.
• There is coordination between contraction of
pharyngeal muscles and relaxation of
cricopharyngeal sphincter at the upper end of
oesophagus.
• Lack of this coordination, i.e. failure of
cricopharyngeal sphincter to relax when
pharyngeal muscles are contracting causes
hypopharyngeal diverticulum.

91. THANK YOU!!