Surgical anatomy and physiology of pharynx

Otorhinolaryngology Department of the First Affiliated Hospital of Sun Yat-Sen University

Otorhinolaryngology Institute of Sun Yat-Sen

University

Rui Xu

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Pharyngeal surgical anatomy

◆ is a musculofascial half-cylinder that links the oral and nasal cavities in the head to the larynx and esophagus in the neck.

◆ the pharyngeal cavity is a common pathway for ‘air ’and ‘food’. (common passages of respiratory systems and digestive systems)

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Pharyngeal surgical anatomy

Relationship:

◆ It is attached above to the base of skull and

continuous below, approximately at the level of the

sixth cervical vertebra, with the top of esophagus.

Anteriorly attached to the margin of nasal cavities,

oral cavities , and larynx. Posterior wall is adjacent to

the prevertebral fascia, and bilateral is close to the

cervical blood vessels and nerves.

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Pharyngeal surgical anatomy

♣ nasopharynx ♣ oropharynx ♣ laryngopharynx (hypopharynx)

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Nasopharynx

◆Position: behind the posterior apertures of the nasal cavities and above the level of the soft palate.

◆ Characteristics: the cavity of the nasopharynx is continuous below with the cavity of the oropharynx at the pharyngeal isthmus.

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Nasopharynx

Relationships of the nasopharynx are as follows: roof---part of sphenoid bone and occipital bone,

adenoids situated at the junction of roof and posterior wall of nasopharynx.

posterior--- first and second cervical vertebra anterior--- posterior naris. lateral---opening of Eustachian (pharyngotympanic)

tube, pharyngeal recesses, the fossae of rosenmuller. Inferior---oral cavity.

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Nasopharynx

There is a large collection of lympoid

tissue (the pharyngeal tonsil) in the

mucosa covering the roof of

nasopharynx.

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Oropharynx

● Position: posterior to the oral cavity, inferior to the level of the soft palate, and superior to the upper margin of the epiglottis.

● Posterior---second and third cervical vertebra

● Anterior--- isthmus oropharyngeus.

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Oropharynx

● Isthmus oropharyngeus ： uvula, free edge of soft palatine,palatoglossal arch, palatopharyngeal arch and dorsum of tongue*.

● Palatine tonsils: on the lateral wall of the oro-

-pharynx, and between the palatoglossal and palatopharyngeal arches **.

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Hypopharynx(Laryngopharynx)

☆ Position: extends from the supior margin of the epiglottis to the top of the esophagus at the level of cervical vertebral Ⅵ

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Hypopharynx(Laryngopharynx)

☆ Relationships of the hypopharynx are as follows:

superior---upper border of the epiglottis

inferior--- lower border of cricoid cartilage contiunes into

oesophagus.

anterior ---by the laryngeal inlet

posterior---the third to sixth cervical vertebra 。

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Hypopharynx(Laryngopharynx)

☆ valleculae: a pair of mucosal pouches, anteriorly to the cavity of laryngopharynx, one on each side, and between the base of tongue and epiglottis.

☆ piriform fossae: another pair of mucosal recess, between the central part of the larynx and more lateral lamina of the thyroid cartilage*.

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Pharyngeal wall*

★ mucosa ： pseudostratified ciliated columnar epithelia, stratified squamous epithelia.

★ fibrous layer: anterior by skull base ， pharyngeal suture formed at the midline of posterior wall.

★ muscular layer ： constrictor pharyngis,longitudinal , levator palati, tensor palati,palato-glossus,etc.**

★ External membrane layer ： fascia membrane.

Pharyngeal wall

muscle posterior att

achmentanterior attachment Innervation Function

superior constrictor

pharyngeal raphe

pterygomandibular raphe and adjent bone on the mandibular and pterygoid hamulus

Vagus nerve [ ]Ⅹ Constriction o

f pharynx

★ Constrictor muscles*:

middleconstrictor

pharyngeal raphe

Upper margin of greaterbhorn of hyoid bone and adjent margins of lesser horn and stylohyoid ligament

Vagus nerve [ ]Ⅹ

Constriction of pharynx

inferiorconstrictor

pharyngeal raphe

Cricoid cartilage,oblique line of thyroid crtilage, and a ligament that spans between these attachments and crosses the crocothyroid muscle

Vagus nerve [ ]Ⅹ Constriction

of pharynx

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Pharyngeal wall★ Longitudinal muscles:Muscle origin Insertion Innervation Function

stylopharyngeus middle side of base of styloid process

pharyngeal wall glossopharyngeal nerve [ ]Ⅸ Elevation of the

pharynx

Salpingppharyngeus inferior aspect of pharyn-geal end of pharyngo-tympanic tube

pharyngeal wall

vegus nerve [ ]ⅩElevation of pharynx

palatopharyngeus upper surface of palatine aponeurosis

pharyngeal wall vegus nerve [ ]Ⅹ Elevation of phary-nx, and closure of the oropharyngeal isthmus

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Fascia

The pharyngeal fascia is seperated into two layers*:

♣ buccopharyngeal fascia: a thin layer, coats the outside

of the muscular part of the wall.

♣ pharyngobasilar fascia: a much thicker layer, lines the i

nner surface

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Fascial spaces ♦ Retropharyngeal space ： ※ Between the buccopharyngeal fascia and prevertebra

l fascia, which extends from skull base to the upper part of

posterior mediastinum (T1,T2).

※ anteriorly by the posterior pharyngeal wall and buccopharyngeal fascia; posteriorly by the cervical vertebra ,their muscles and fascia. One on each side, and seperated from parapharyngeal space. It contains retropharyngeal lymph nodes and connective tissue.

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♦ parapharyngeal space ：

From the skull base above to the glossal bone below.

It’s occupied by the carotid vessels, internal jugular

vein, deep cervical lymph nodes, the last four cranial

nerves and cervical sympathetic trunk.

Fascial spaces

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Pharyngeal lymphoid tissue

Tonsil occur mainly in three areas: ▪ the pharyngeal tonsils, known as adenoids when enlarged,

is in the midline on the roof of the nasapharynx.

▪ the palatine tonsils are on each side of the oropharynx between the palatoglossal and palatopharyngeal arches

▪ the lingual tonsil refer collectively to numerous lymphoid nodules on the posterior one-third of the tongue.

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Palatine tonsils

♠ tortuous crypts

♠ Capsule: lateral two-third of each tonsil, a well

defined structure composed of fibrous tissue, elastic

tissue and muscle fibres.

♠ Blood supply ： A. palatina descendens, A. palatina

ascendens, A. pharyngea ascendens, A. facialis and

A. dorsales linguae

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Vessels supply of pharynx

♣ Arteries ◆ upper parts of pharynx: the ascending pharyn-

geal a.,the ascending palatine and tonsillar branches of the facial a.,numerous branches of the maxillary and the lingual a.

◆ lower parts of pharynx: pharyngeal branches from the inferior thyroid a.

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Vessels supply of pharynx

♣ Veins ◆ veins of the pharynx form a plexus, which

drains into: superiorly : pterygoid plexus in the infratemporal

fossa.

inferiorly : the facial and internal jugular veins

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Innervation of the pharynx

♣ pharyngeal plexus*: pharyngeal branch of

the vagus nerve[ ], superior laryngeal branch Ⅹof the vagus nerve[ ], and pharyngeal branch Ⅹof the glossopharyngeal nerve [ ]Ⅸ

♣ trigeminal nerve (tensor veli palatini,etc.)

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Lymphatic vessels from the pharynx

♣ deep cervical nodes and include retropharyngeal, paratracheal , and infrahyoid nodes.

♣ the palatin tonsils drain through jugulodigastric nodes

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Physiology of pharynx

1. Respiration

2. Swallowing

3. Language formation

4. Protective function

5. Modulate barometric pressure

6. Tonsil immunologic function (IgA, IgG and small amount of IgD. These are secreted into pharynx and increased when inflammation)

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Symptomatology of Pharynx

● pharyngeal pain

● pharyngeal abnormal sensation

● dysphagia

● heterophony

● drink back flowing