Anatomy of respiratory system

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Anatomy of pharynx
Dr. Mohammad Mahmoud Mosaed

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Pharynx
• Musculomembranous tube which is deficient anteriorly
extends From the base of the skull to the level of the 6th
cervical vertebra
• It connects to the
• Nasal cavity, mouth and Larynx
• Function:
• Passage way for food, air, water
• Resonating chamber
• Immune function, tonsils
• It connects to the esophagus at the level of the 6th
cervical vertebra.

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Parts of the pharynx
• The pharynx divided
into 3 parts
• Nasopharynx behind
the nose
• Oropharynx behind
the oral cavity
• Laryngopharynx
behind the larynx

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Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
(b) Regions of the pharynx

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Nasopharynx
• Air passageway posterior to the nasal cavity extends from the base of the
skull to the level of the soft patate.
• It communicates with the nose through the posterior nasal aperatures
• It communicates with the oropharynx through the pharyngeal isthmus.
• On each side (the lateral walls) it present the medial or pharyngeal opening
of the auditory (Pharyngotympanic) tube which connects the nasopharynx
with the tympanic cavity.
• The elevation of the opening of the tube in the nasopharynx called tubal
elevation caused by cartilagenous part of the auditory tube
• Around the tubal elevation there is a salpingopharyngeal fold caused by
salpingopharyngeal muscle and behind the fold there is a salpingopharyngeal
recess
• Soft palate and uvula close nasopharynx during swallowing
• In the submucosa of the roof is a collection of lymphoid tissue called the
pharyngeal tonsil (adenoids)

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Sphenoid sinus Frontal sinus
Nasal meatuses
(superior, middle,
and inferior)
Nasopharynx
Uvula
Palatine tonsil
Isthmus of the
fauces
Posterior nasal
aperture
Opening of
pharyngotympanic
tube
Pharyngeal tonsil
Oropharynx
Laryngopharynx
Vocal fold
Esophagus
(c) Illustration
Nasal conchae
(superior, middle
and inferior)
Nasal vestibule
Nostril
Nasal cavity
Hard palate
Soft palate
Tongue
Lingual tonsil
Epiglottis
Hyoid bone
Larynx
Thyroid cartilage
Vestibular fold
Cricoid cartilage
Thyroid gland
Trachea
Cribriform plate
of ethmoid bone

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Clinical Notes
1. The nasal part of the pharynx may be viewed clinically by
a mirror passed through the mouth
2. Adenoids
• Definition: Excessive hypertrophy of the lymphoid tissue
associated with infection, causes the pharyngeal tonsils to
become enlarged.
• Symptoms: The patient snore loudly at night and to
breathe through the open mouth due to blocks of the
posterior nasal openings by enlarged pharyngeal tonsils
• Complications: The close relationship of the infected
lymphoid tissue to the auditory tube may be the cause of
deafness and recurrent otitis media.
• Treatment: Adenoidectomy.

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Oropharynx
• Passageway for food and air, it lies behind the oral
cavity.
• It extends from the level of the soft palate to the
upper border of the epiglottis.
• Isthmus of the fauces (oropharyngeal isthmus): is
the opening of the oral cavity into the oropharynx.
• The pharyngeal part of the tongue is connected to
the epiglottis by the 2 lateral glossoepiglottic folds
and one median glossoepiglottic folds.The
depression on each side of the median
glossoepiglottic fold is called the vallecula

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Laryngopharynx
• It extends from the level of the tip of the epiglottis to
the termination of the pharynx in the oesophagus at
the level of the 6th
cervical vertebra.
• On each side of the laryngeal inlet there is a
depression called piriform fossa bounded medially
by the aryepiglottic fold and laterally by lamina of
the thyroid cartilage. Clinically, it is important because it
is a common site for the lodging of sharp ingested bodies
such as fish bones. The presence of such a foreign body
immediately causes the patient to gag violently. Once the
object has become jammed, it is difficult for the patient to
remove it without a physician's assistance.

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Blood supply
• Arteries
Arteries that supply upper parts of the pharynx include:
• the ascending pharyngeal artery;
• the ascending palatine and tonsillar branches of the facial artery;
• numerous branches of the maxillary and the lingual arteries
All these vessels are from the external carotid artery.
Arteries that supply the lower parts of the pharynx include;
• pharyngeal branches from the inferior thyroid artery, which
originates from the thyrocervical trunk of the subclavian artery.
• Veins
• Veins of the pharynx form a plexus, which drains superiorly into
the pterygoid plexus in the infratemporal fossa, and inferiorly into
the facial and internal jugular veins

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Lymphatics
•Lymphatic vessels from the pharynx
drain into the deep cervical nodes and
include retropharyngeal (between
nasopharynx and vertebral column),
paratracheal, and infrahyoid

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•All muscles of the pharynx are
innervated by the vagus nerve mainly
through the pharyngeal plexus, except
for the stylopharyngeus, which is
innervated by a branch of the
glossopharyngeal nerve .
Motor innervation

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Sensory innervation
• Each subdivision of the pharynx has a different
sensory innervation:
• The nasopharynx is innervated by a pharyngeal
branch of the maxillary nerve
• The oropharynx is innervated by the
glossopharyngeal nerve via the pharyngeal plexus;
• The laryngopharynx is innervated by the vagus
nerve via the pharyngeal plexus.