The pharynx is a conical tube that extends from the base of the skull to the lower border of the cricoid cartilage. It is divided into three parts: the nasopharynx, oropharynx, and hypopharynx. The pharynx acts as a passageway for air and food and plays an important role in swallowing, speech, and drainage of the middle ear. It contains important structures like the tonsils and adenoids that help protect the respiratory and digestive tracts from infection. Blood supply comes from branches of the external carotid artery and it is innervated by nerves from the pharyngeal plexus including the vagus and glossopharyngeal nerves.

1. Anatomy and
Physiology of Pharynx
Dr. Vijay Kumar
Dr. Vijay Kumar

2. Pharynx
Pharynx is a conical fibromuscular tube
forming upper part of aero-digestive tract
12-14 cms, extends from base of skull to
lower border of cricoid cartilage (C6).
Width is 3.5 cms at base & 1.5 cms at
pharyyngo-oesophageal junction, which is
the narrowest part in GIT.

3.  Mucous membrane
 Pharyngeal aponeurosis / Pharyngobasilar
fascia
 Muscular coat
 Buccopharyngeal fascia
 Ciliated columnar in nasopharynx & stratified
squamous in rest of pharynx

4. Killian’s dehiscence
 Inferior constrictor muscle-
thyropharyngeus –oblique fibres
cricopharyngeus – transverse fibres
 Potential gap- Killian’s Dehiscence
 “Gateway of tears” – perforation can occur at
this site during oesophagoscopy.
 Pharyngeal pouch- herniation of pharyngeal
mucosa

5. Waldeyer’s Ring
Subepithelial layer of lymphoid tissue
 Nasopharyngeal tonsil/adenoids
 Palatine tonsil
 Tubal tonsil
 Lateral pharyngeal bands
 Nodules-posterior pharyngeal wall

6. Pharyngeal Spaces
 Retropharyngeal space- from base of skull
to bifurcation of trachea between
buccopharyngeal fascia & prevertebral fascia.
Divided by median raphe into two (space of
Gillette)
 Prevertebral space - between vertebral
bodies & prevertebral fascia, extends from
base of skull to coccyx

7. Parapharyngeal space
 Medial: buccopharyngeal fascia covering
constrictors
 Posterior: prevertebral fascia
 Lateral: medial pterygoid muscle, mandible.
 Styloid complex- divides into anterior &
posterior compartment.
Antr- tonsillar fossa medially & pterygoid
muscle laterally
Postr- pharyngeal wall med & parotid
laterally. Carotid art, jugular vein, IX, X, XI,
XII CN, & nodes

8. Pharynx
 Nasopharynx, Oropharynx & Hypopharynx
Nasopharynx
 Epipharynx: from base of skull to plane
passing through hard palate
 Roof: basisphenoid & basiocciput
 Posterior wall: atlas vertebra with muscles
 Floor: anteriorly soft palate & posteriorly
communicates with the oropharynx through
nasopharyngeal isthmus

10. Lateral wall: E.tube 1.25cms behind IT
Torus tubaris- elevation behind tubal opening
Fossa of Rosenmuller- site for origin of
Nasopharyngeal Carcinoma
Salpingopharyngeal fold
Tubal tonsil: part of Waldeyer’s ring
Adenoids-Nasopharyngeal tonsil
upto12 years, later atrophies

11. Nasopharyngeal bursa
Epithelial lined median recess within
adenoids
Extends from pharyngeal mucosa to
basiocciput
Represents attachment of notochord to
pharyngeal entoderm during embryonic
life
Infection – persistent postnasal discharge
Thornwaldt’s disease- abscess

12.  Rathke’s pouch: remniscent of buccal
mucosal invagination,forming antr lobe of
pituitary. Craniopharyngioma may arise from
this site
 Sinus of Morgagni: space between base of
skull & upper free border of superior
constrictor . E.tube, tensor veli palatine,
levator veli paltine enters along with ascending
palatine artery br of facial artery
 Passavant’s ridge: mucosa ridge raised by
palatopharyngeus. Deglutition, cuts off NP
from OP

13.  Lined by pseudostratified ciliated columnar
epithelium
 Lymphatics drain into upper deep cervical nodes
either directly or thro’ retro/parapharyngeal nodes
Functions
 Conduit of humidified air into larynx/trachea
 Ventilates ME thro’ E.tube, equalizes air pressure.
 Cuts off oropahrynx during deglutition, vomiting,
speech
 Resonating chamber
 Drainage channel for mucous secreted by nasal
glands

14. Oropharynx
 Extends from plane of hard palate above to plane of
hyoid bone below
 Communicates with oral cavity thro’ oropharyngeal
isthmus.
 Posterior wall: related to retropharyngeal space, C2-C3
 Anterior wall: above opens into oral cavity, & below
related to base of tongue, lingual tonsil, valleculae
 Lateral wall: anterior & posterior pillars, faucial tonsil
 Lower limit is by upper border of epiglottis &
pharyngoepiglottic folds

15.  Lymphatics drain into upper jugular chain-JD
nodes, also to retro & para pharyngeal nodes.
Functions
 Conduit for passage of air & food
 Pharyngeal phase of deglutition
 Vocal tract for certain speech sounds
 Taste sensation-BOT, soft palate, pillars, PP
wall
 Local defence & immunity at entrance of
aerodigestive tract- Waldeyer’s ring

16. Hypopharynx (Laryngopharynx)
It lies behind & sides of larynx
Extends from plane passing from hyoid
bone to lower border of cricoid cartilage,
(C3-C6).
Three regions: Pyriform sinus, post cricoid
region & posterior pharyngeal wall.
Pyriform fossa: either side of larynx.
Internal laryngeal nerve runs submucosally
in lat wall, cause referred pain in carcinoma

18.  Post-cricoid region: cricoid lamina, site for
carcinoma in pt’s with Plummer-Vinson syndrome
 Posterior pharyngeal wall: from level of hyoid bone
to crcoarytenoid joint.
 Lymphatic drainage: upper jugular chain,
parapharyngeal nodes, supraclavicular.
Functions:
 Conduit for air & food, Vocal tract resonance
 Takes part in deglutition
Failure of cricopharyngeal sphincter to relax when
pharyngeal muscles contract- hypopharyngeal
diverticulum

19. Structures passing through
Above superior constrictor
 E.tube, tensor palati, levator palati muscles
 Palatine br ascending pharyngeal artery
Between superior & middle constrictor
 Stylopharyngeus muscle, glossopharyngeal n
Between middle & inferior constrictor
 Internal laryngeal n, superior laryngeal vessels.
Below inferior constrictor
 Recurrent laryngeal nerve, inferior laryngeal art

20. Blood supply: branches of external carotid art
 Ascending pharyngeal, Dorsal lingual artery
 Ascending palatine & tonsillar artery
 Branches of internal maxillary artery
Nerve supply: pharyngeal plexus formed by
 Pharyngeal br of vagus & glossopharyngeal
 Pharyngeal br of superior cervical
sympathetic ganglion
 Vagal fibres are motor, glossopharyngeal is
sensory & sympathetic is vasomotor

21. Functions of Pharynx
 Deglutition
 Protection from aspiration
 Part of respiratory & food passage
 Speech adds resonance to the voice
 Waldeyer’s ring is involved
 Taste sensation
 Mucous from respiratory tract is swallowed
 E.tube ventilates & drains the middle ear cleft

22. Thank You..