Anatomy of Pharynx

1. Dr Ajeet Kumar Khilnani
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2.  Conical fibromuscular tube etending from base
of skull to lower border of cricoid cartilage (12-
14 cm long, 3.5 cm at base and 1.5 cm at
pharyngo-oesophageal junction)
 4 layers (from within outwards)
- Mucous membrane
- Pharyngeal aponeurosis (pharyngobasilar fascia)
- Muscular coat
External Layer: S/M/I constrictor muscles
Internal Layer: Stylo, Salpino & Palatopharyngeus
- Buccopharyngeal fascia
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4.  Gap between thyropharyngeus &
cricopharyngeus parts of inferior constrictor
muscle
 “Gateway of tears”
 May perforate during oesophagoscopy
 Site for herniation of pharyngeal mucosa in
cases of pharyngeal pouch
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6.  Lymphoid tissue scattered throughout the
pharynx in its subepithelial layer
- Nasopharyngeal tonsil (Adenoids)
- Palatine tonsils
- Lingual tonsil
- Tubal tonsil (in fossa of Rosenmuller)
- Lateral pharyngeal bands
- Nodules (in posterior pharyngeal wall)
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8.  Retropharyngeal space
- Extends from base of skull to bifurcation of
trachea
 Parapharyngeal space
- Contains carotid vessels, jugular vein, last
four CNs & cervical sympathetic chain
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10.  Roof: Basisphenoid & basiocciput
 Posterior wall: Arch of atlas vertebra
 Floor: Soft palate anteriorly, deficient
posteriorly
 Anterior wall: Posterior choanae
 Lateral wall
- Pharyngeal opening of ET
- Torus tubaris: d/t cartilage of ET
- Fossa of Rosenmuller: Recess above and
behind the tubal elevation. It is commonest
site for origin of CA
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12.  Nasopharyngeal tonsil (Adenoids)
- At junction of roof & posterior wall
- Increases in size up to 6 years & then
atrophies
 Nasopharyngeal bursa
- Epithelial lined median recess found within
adenoid mass
- It represents the attachment of notochord
- Thornwaldt’s disease: Abscess in the bursa
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13.  Rathke’s pouch (dimple above the adenoids)
- It is reminiscent of the buccal mucosal
invagination, to form the anterior lobe of
pituitary
- Craniopharyngioma may arise from it
 Sinus of Morgagni
- Space between base of skull & upper free
border of superior constrictor muscle
- Through it enters the ET, levator veli palatini,
tensor veli palatini & ascending palatine
artery (branch of facial artery)
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15.  Passavant’s Ridge
- It is a mucosal ridge raised by fibres of
palatopharyngeus
- It encircles the posterior & lateral wall of
nasopharyngeal isthmus
- During deglutition or speech, soft palate
comes in contact with this ridge to cut off
nasopharynx from oropharynx
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16.  Conduit for humidified air to the larynx
 Ventilates the middle ear (ET)
 During swallowing, speech, vomiting &
gagging, the Passavant’s ridge helps to cut
nasopharynx from oropharynx
 Acts as a resonating chamber (rhinolalia
clausa & aperta)
 Acts as a drainage channel for the mucus
secreted by nasal & nasopharyngeal glands
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17.  Posterior wall: Retropharyngeal space (C2,C3)
 Anterior wall: Deficient above, below it is
formed by BOT, lingual tonsils, valleculae
(cup shaped depressions lying b/w BOT &
epiglottis)
 Lateral wall: Palatine tonsil, anterior pillar
(palatoglossus muscle) & posterior pillar
(palatopharyngeus muscle)
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20.  Conduit for passage of air & food
 Helps in pharyngeal phase of deglutition
 Forms part of vocal tract for certain sounds
 Helps in appreciation of taste
 Provides local defence & immunity
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21.  Lies opposite to C3 to C6 vertebrae
 Subdivided into three regions
- Pyriform sinus (fossa): It forms the lateral
channel for food. Foreign bodies may lodge
here. Internal laryngeal nerve runs
submucosally in the lateral wall of sinus & is
easily accessible for LA. In CA of pyriform
sinus pain is referred to ear through this
nerve
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22. - Post cricoid region: Between upper & lower
borders of cricoid lamina. It is common site
for CA in females with PV syndrome
- Posterior pharyngeal wall
 Functions of Hypopharynx
- Common pathway for air and food
- Forms part of vocal tract for certain sounds
- Helps in deglutition
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