باسل

Pharynx

Dr. Basil M.N. Saeed
Assistant Professor
Department of Surgery
College of Medicine
Mosul University

Pharynx

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(( 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

-Communicates inferiorly 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 larynx BUT 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.

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 of 2 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 laterally connected 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

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, and the internal jugular vein.
Lymphatic Drainage
Deep cervical chain of lymph nodes.

Blood Supply of the Tonsil

Sensory Nerve Supply
Nasopharynx: Maxillary nerve, trigeminal
Oropharynx: Glossopharyngeal nerve, trigeminal
Laryngopharynx: vagus nerve, and glossopharyngeal.
Motor supply
All the muscles of pharynx, except the stylopharyngeus, supplied by the pharyngeal plexus.
Pharyngeal branches of the IX and X nerves, and sympathetic fibers from the superior cervical ganglion.
The stylopharyngeus is supplied by the glossopharyngeal nerve

Nerve Supply of the Pharynx

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.


Retropharyngeal Space (Space of Gillette

Contents:

Retropharyngeal lymph nodes of Rouviere.
Usually disappear spontaneously during the 3rd or 4th year of life.

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.
Parapharyngeal Space

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

• 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).
Physiology of the Pharynx

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


Symptoms of Pharyngeal Diseases

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.