Pharynx Dr. Basil M.N. Saeed Assistant Professor Department of Surgery
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Transcript of Pharynx Dr. Basil M.N. Saeed Assistant Professor Department of Surgery
Pharynx Dr. Basil M.N. Saeed Assistant Professor Department of
Surgery
College of Medicine Mosul University Pharynx Oropharynx
Laryngopharynx (( Hypopharynx))
Is a funnel-shaped fibromuscular tube, 10-12 cm in length in
adults. Extends from the base of the skull to the level of C6. The
pharynx is divided anatomically into 3 parts;Nasopharynx Oropharynx
Laryngopharynx (( Hypopharynx)) Behind : The Nose The Mouth The
larynx Nasopharynx Oropharynx Laryngopharynx (Hypopharynx)
Seen from behind Nasopharynx Oropharynx Laryngopharynx
(Hypopharynx) Nasopharynx(( Postnasal Space))
This extends from the base of the skull to the hard palate. At the
junction of the roof and posterior wall lies a small mass of
lymphoid tissue called adenoids (nasopharyngeal tonsil). On the
lateral wall, there are the openings of the Eustachian tubes.
Behind which are hollows called the fossa of Rosenmuller, which is
the site of nasopharyngeal malignancy -Communicatesinferiorly with
the oropharynx through the velo-pharyngeal sphincter Oropharynx
Extends from the level of hard palate to the level of hyoid bone
and opens anteriorly into the oral cavity. Behind the oral cavity
(in front of 2nd&3rd Cervical vertebra) The palatine tonsils
are situated in it's lateral wall Between the ant. and post
tonsillar pillars. From the soft palate superiorly to tip of
epiglottis inferiorly Communicates: Anteriorly with the oral cavity
Superiorly with the nasopharynx Inferiorly with the hypopharynx
Hypopharynx Behind the Larynx (in front of 3rd to 6th Cervical
vertebra) From the tip of epiglottis superiorly to the lower border
of cricoid cartilage inferiorly Communicates: Anteriorly with the
Larynx Superiorly with the oropharynx Inferiorly with the esophagus
The hypopharynx does not only
lie behind the larynxBUT also Projects laterally on each side of
the larynx and is formed of : Postcricoid region ( behind the
larynx) Two pyriform fossae (on each side of the larynx Pharyngeal
Wall Histology Wall Histology The pharyngeal wall consists of 4
layers:
1. Mucous membrane. 2. Pharyngobasilar fascia. 3. Muscle layer. 4.
Buccopharyngeal fascia. 1- Mucus Membrane The lining epithelium is
stratified squamous except in the nasopharynx, where columnar
epithelium is found. 3- Muscular Layer 2- Pharyngobasilar
fascia
This fascia is strengthened posteriorly by a strong band called the
median raphae. 3- Muscular Layer I- Circular (outer): which consist
of 3 constrictor muscles overlapping one another from below
upwards. 1. Superior constrictor. 2. Middle constrictor. 3.
Inferior constrictor. The inferior constrictor muscle is composed
of2 parts:
a. Thyropharyngeus (oblique): arises from the thyroid cartilage. b.
Cricopharyngeus (transverse): arises from the cricoid cartilage and
passes transversely backwards forming the upper oesophageal
sphincter. All the constrictor muscles are inserted posteriorly
into the median pharyngeal raphae. Functions The constrictor
muscles propel the bolus of food down into the esophagus The
Cricopharygeus (lower fibers of the inferior constrictor) act as a
sphincter, preventing the entry of air into the esophagus between
the acts of swallowing Killian dehiscence: this is a potential gap
between the fibers of the thyropharyngeus and cricopharyngeus. The
mucous membrane may bulge between these two muscles when there is
incoordination of the pharyngeal peristaltic waves. Pharyngael
Pouch II- Longitudinal (internal): these muscles elevate the larynx
and shorten the pharynx during deglutition: 1. Stylopharyngeus. 2.
Salpingopharyngeus. 3. Palatopharyngeus Buccopharyngeal
Fascia
This fascia is loosely attached posteriorly to the prevertebral
fascia and laterallyconnected to the styloid process and to the
carotid sheath Subepithelial lymphoid tissue of the pharynx
(Waldeyer's ring)
Is a collection of sub-epithelial lymphoid tissue around the
entrance of the respiratory and alimentary tracts. Waldeyer's ring
is formed by
1. Nasopharyngeal tonsil (adenoid). 2. Tubal tonsils: lie behind
the openings of the Eustachian tubes. 3. Palatine tonsils. 4.
Lingual tonsils: which is embedded in the posterior 1/3 of the
tongue. 5. Lateral pharyngeal bands behind the posterior tonsillar
pillar. 6. Lymphoid nodules scattered on the posterior pharyngeal
wall Hypertrophy of the lymphoid tissue of Waldeyer's ring occurs
in the earlier years of childhood. Maximum bulk is obtained at the
age of 3- 6 years, and in old age it atrophies Waldeyer's ring is
characterized by:
1. Sub-epithelial lymphoid tissue. 2. Lack a definite capsule. 3.
They have efferent lymph vessels, but no afferent vessels. 4.
Function as one unit: when a member of it is removed, the others
parts undergo compensatory hypertrophy. Palatine Tonsils Two masses
of lymphoid tissue situated on each side of the oropharynx. The
medial surface is exposed in the pharynx and is pitted by a number
of crypts. The tonsil is related anteriorly and posteriorly to the
palatoglossus and palatopharyngeus muscles. Laterally the tonsil is
enclosed by a dense fibrous capsule separating the tonsil from the
superior constrictor muscle (tonsillar bed). This capsule provide a
convenient plane of separation of the tonsil during tonsillectomy
Palatine tonsil Blood Supply of the Tonsil
The main supply is the tonsillar branch of the facial artery, and
decsending palatine artery. The venous drainage is to the
paratonsillar vein which drains to the pharyngeal plexus, andthe
internal jugular vein. Lymphatic Drainage Deep cervical chain of
lymph nodes. Nerve Supply of the Pharynx
Sensory Nerve Supply Nasopharynx: Maxillary nerve, trigeminal
Oropharynx: Glossopharyngeal nerve, trigeminal Laryngopharynx:vagus
nerve, and glossopharyngeal. Motor supply All the muscles of
pharynx, except thestylopharyngeus, supplied by the
pharyngealplexus. Pharyngeal branches of the IX and X nerves,
andsympathetic fibers from the superior cervicalganglion. The
stylopharyngeus is supplied by theglossopharyngeal nerve
Retropharyngeal Space (Space of Gillette
This space lies behind the pharynx and extends from the base of the
skull to the superior mediastinum. The anterior wall is formed by
the posterior pharyngeal wall and it's covering buccopharyngeal
fascia. The posterior wall is formed by the cervical vertebrae and
their covering muscles and fascia. Contents: Retropharyngeal lymph
nodes of Rouviere. Usually disappear spontaneously during the 3rd
or 4th year of life. Parapharyngeal Space This potential space lies
lateral to the pharynx and connects posteriorly with the
retropharyngeal space. It extends from the base of the skull to the
hyoid bone. It's bounded medially by the superior constrictor
muscle. Laterally lies the medial pterygoid muscle, the mandible
and the parotid gland. It's posterior wall is the prevertebral
muscles and fascia. Contents 1. Deep cervical lymphnodes. 2. The
last 4 cranial nerves and the cervical sympathetic trunk. 3. Great
vessels of the neck: carotid and internal jugular vein.
Parapharyngeal space Physiology of the Pharynx
1. Food and air inlet. 2. Play an important role in speech through
vocal resonance and articulation. 3.The protective function of
Waldeyer's ring. 4. Deglutition: it's divided into 3 stages: a.
Oral stage (voluntary). b. Pharyngeal stage (involuntary). c.
Oesophageal stage (involuntary). Symptoms of Pharyngeal
Diseases
1- Sore throat (pain) a. Inflammatory. b. Neoplastic. c.
Neurological: IX neuralgia. d. Blood dyscrasia: agranulocytosis and
leukaemia. 2- Dysphagia: is difficulty in swallowing whereas
odynophagia is painful swallowing. Dysphagia: Intraluminal,Luminal
Extraluminal 3- Difficulty in breathing like stridor in Ludwig's
angina. 4- Difficulty in speech: Paralysis of the soft
palate(hypernasalily). 5- Neck mass Cervical lymphadenopathy
Examination Nasopharynx: This can be done with postnasal mirror and
tongue depressor (posterior rhinoscopy), and it can be thoroughly
examined by rigid and flexible endoscopes. Oropharynx: It is simple
with tongue depressor; palpation may be needed for the tongue.
Hypopharynx: It can be done with the use of laryngeal mirror to
examine the larynx too. It can be done thoroughly with the use of
endoscope. Neck examination: for cervical lymphadenopathy. Other
areas : ears are examined for secretory otitis media in cases of
nasopharyngeal tumours Investigations of pharyngeal diseases
Radiography: Plain films like lateral X-Ray of the skull, is needed
in nasopharyngeal mass like adenoids, and can demonstrate bone
erosion in cases of nasopharyngeal cancer. Contrast films: barium
swallow is needed in the diagnosis of pharyngeal pouch, esophageal
web and hypopharyngeal mass. CT scan MRI scan. Laboratory
investigations: CBC, ESR, serum iron and iron binding capacity,
monospot test, serology for toxoplasma, brucella, CMV and HIV.
Biopsy for suspected lesions in the pharynx may be needed.