PHARYNX
Dr. Shawky M. Tayel
- Professor of Anatomy, Embryology & Human Genetics
Anatomy Dep., Alexandria Faculty of Medicine,
- Genetics Consultant, Clinical Genomic Center
www.alexmedicine.com/alexgenomics.htm ,
- Genetics Consultant, Suzanne Mubarak Regional Centre for
Women's Health & Development www.smcalex.org ,
- Fellow, Medical College of Ohio, USA,
- Member, American Society of Human Genetics.
PHARYNX
Definition:
• It is a musculomembrenous tube lying
behind the nose, mouth
and larynx.
• It is about 12 cm long.
• It extends from the base
of the skull and ends
opposite 6th cervical
vertebra (level of lower
border of cricoid
cartilage)
Relations of the pharynx
Anteriorly:
• Nasal cavity, mouth and
larynx.
Posteriorly:
• Vertebral column,
prevertebral fascia and
muscles.
Superiorly:
• Sphenoid and basilar part
of occipital bones.
Inferiorly:
• It is continuous with
esophagus.
Divisions of the pharynx:
•
The pharynx is divided into 3 parts from
above downwards;
1. Nasopharynx
2. Oropharynx.
3. Laryngopharynx.
Oropharynx
• It is the middle part of
the pharynx.
• It extends from soft
palate to upper border
of epiglottis.
• It communicates with
the mouth through the
oropharyngeal
isthmus.
• Structures in the
oropharynx:
• Palatine tonsil
enclosed between
the palatoglossal
fold (ant.) and
palato-pharyngeal
fold (post.)
Palatine tonsil
• It is a collection of
lymphoid tissue on the
lateral wall of the
oropharynx on each
side.
• It lies in a triangular
depression called
tonsillar fossa.
• This fossa is bounded
by palatoglossal arch
(fold) anteriorly and
palatopharyngeal arch
(fold) posteriorly.
Relations of palatine tonsils
• Anteriorly: Palatoglossal
arch.
• Posteriorly:
Palatopharyngeal arch.
• Superiorly: Soft palate.
• Inferiorly: Posterior third
of the tongue.
• Medially: Cavity of the
oropharynx.
• Laterally (tonsillar bed):
Superior constrictor
muscle, paratonsillar vein
and tonsillar artery.
•
Arterial supply of
tonsil:
1. Tonsillar branch of
facial artrey.
2. Twigs from dorsalis
lingulae artery.
3. Twigs from ascending
pharyngeal artery (from
ECA).
4. Twigs from ascending
palatine artery (from facial).
• Venous drainage:
Paratonsillar vein to
pharyngeal plexus.
• Lymph drainage:
Upper deep cervical lymph nodes mainly
jugulodigastric lymph nodes.
• Nerve supply:
1. Tonsillar branch of glossopharyngeal
nerve.
2. Lesser palatine nerve.
Laryngopharynx:
• It is the lower division of
the pharynx.
• It extends from the lower
border of epiglottis to the
upper border of cricoid
cartilage.
• Inferiorly it is continuous
with the esophagus at level
of 6th cervical vertebra.
• It shows a depression on
each side of the laryngeal
inlet called piriform fossa.
Wall of the pharynx
•
1.
2.
3.
4.
From inside outwards, the wall of the
pharynx is formed by:
Mucosa.
Inner fibrous coat (pharyngobasilar
fascia). From base of skull to esophagus
Muscles.
Outer fibrous coat (buccopharyngeal
fascia)
Muscles of the pharynx:
•
1.
a.
b.
c.
2.
3.
4.
It consists of:
The 3 constrictors:
Superior constrictor.
Middle constrictor.
Inferior constrictor.
Stylopharyngeus muscle.
Palatopharyngeus muscle.
Salpingopharyngeus muscle.
Constrictor muscles of the pharynx
Origin:
• Superior constrictor; posterior
border of medial pterygoid plate.
• Pterygoid hamulus.
• Pterygomandibular raphe.
• Posterior end of mylohyoid line.
• Middle constrictor:
• Lower part of stylohyoid
ligament.
• Lesser and greater cornu of hyoid
bone.
• Inferior constrictor:
• Thyroid and cricoid cartilages.
Insertion:
Pharyngeal raphe:
A strong median
fibrous raphe that
receives the
insertion of all
constrictors on the
back of the pharynx.
Its upper end is
attached to the
pharyngeal tubercle.
• Nerve supply of constrictor
muscles:
Pharyngeal plexus
• Action of constrictor muscles:
• During swallowing, contraction of
the upper fibres of the superior
constrictor will pull the pharyngeal
wall forwards. This will help the
soft palate to close the
nasopharyngeal isthmus (between
the nasopharynx and oropharynx).
• The successive contractions of the
superior, middle and inferior
constrictor muscles propel the bolus
of food downwards to the
oesophagus.
•
•
•
•
•
Stylopharyngeus
muscle:
Origin: from styloid
process of the
temporal bone.
Insertion: into the
posterior border of
thyroid cartilage.
Nerve supply:
Glossopharyngeal
nerve (IX).
Action: Elevation of
the larynx and pharynx
during swallowing.
–
•
•
•
•
Salpingopharyngeus
muscle:
Origin: cartilaginous
part of auditory tube.
Insertion: It blends
with palatopharyngeus
muscle.
Nerve supply:
Pharyngeal plexus.
Action: It helps in
elevation of the
pharynx.
•
•
•
•
•
Palatopharyngeus
muscle:
Origin: Hard palate
and palatine
apponeurosis.
Insertion: The lamina
of thyroid cartilage.
Nerve supply: Cranial
part of accessory nerve
through the pharyngeal
plexus.
Action: Depression of
the palate and
narrowing the
nasopharyngeal isthmus
during deglutition.
• Motor:
• All muscles of pharynx are supplied by
cranial part of accessory nerve through
pharyngeal branch of vagus except
Stylopharyngeus m. (glossopharyngeal
nerve).
Pharyngeal plexus:
•
It is nerve plexus on the outer wall of the
pharynx.
• It is formed by:
1. Pharyngeal branch of vagus carrying the fibers of
cranial part of accessory nerve (motor
component).
2. Pharyngeal branch of glossopharyngeal (sensory
component).
3. Branches of superior cervical sympathetic
ganglion (sympathetic component).
Blood supply of the pharynx:
• Arterial:
1. Ascending pharyngeal artery.
2. Ascending palatine artery.
3. Facial artery.
4. Lingual artery.
5. Pharyngeal branch of maxillary artery.
• Venous drainage:
Pharyngeal plexus of veins into internal jugular vein.
Lymph drainage:
1.
2.
3.
4.
Upper deep cervical lymph nodes.
Lower deep cervical lymph nodes.
Retropharyngeal lymph nodes.
Para tracheal lymph nodes.
Gapes of the pharynx:
• 1. A gap between the upper
border of the superior
constrictor and the skull base
- It gives passage to levator
palati, ascending palatine
artery, and auditory tube.
• 2. A gap laterally between the
superior and middle
constrictors
- It gives passage to the
following:
a. Stylopharyngeus passing
down to the pharynx.
b. Glossopharyngeal nerve
passes forwards to the tongue.
•
3. A gap laterally between
the middle and inferior
constrictors
- The structures passing
through this gap are:
a. Internal layryngeal nerve.
b. Superior laryngeal artery.
• 4. A gap at the lower
border of the inferior
constrictor
- It is pierced by:
a. Inferior laryngeal artery.
b. Recurrent laryngeal
nerve.