nasalpharynx.txt

• 15 cm long half-cylinder located posterior to:
• • the nasal and oral cavities in the head and to
• • the larynx in the neck.
• The pharynx is continuous with the esophagus and it conducts food to it. The pharynx also conducts air to the larynx, trachea, and lungs.
• It extends from the base of the skull to the C6 vertebral level.
• 

• The posterior apertures of the nasal cavity open into the nasopharynx;
• superior to soft palate

• The posterior opening of the oral cavity opens into the oropharynx;
• soft palate superior, epiglottis inferior

• The superior opening of the larynx opens into the laryngopharynx.
• inferior to epiglottis

• (a) skeletal muscles
• (b) fascia (lined by mucosa and submucosa).
• Gaps between the muscles are reinforced by the fascia and provide routes for structures to pass through the wall.

• • the superior, middle, and inferior pharyngeal constrictor muscles which have their fibers oriented in a circular direction, and
• • the longitudinal muscles which have their fibers oriented vertically.

• separated into two layers which sandwich the muscles between them:
• • the pharyngobasilar fascia is a thicker layer that lines the inner surface of the pharynx. This fascia is covered by a layer of mucosa and a layer of submucosa.
• • the buccopharyngeal fascia is a thin layer surrounding the outside of the
• muscular part of the wall.

thicker layer that lines the inner surface of the pharynx. This fascia is covered by a layer of mucosa and a layer of submucosa.

thin layer surrounding the outside of the muscular part of the wall.

• from internal to external:
• 1. The mucosa, which lines the pharynx
• 2. The submucosa
• 3. The pharyngobasilar fascia, which attaches superiorly to the skull
• 4. The muscularis, which includes the two layers of muscles previously mentioned
• 5. The buccopharyngeal fascia, which contains the pharyngeal plexus of nerves and veins
• 6. The retropharyngeal space, which lies between the buccopharyngeal fascia and the fascia that covers the vertebrae anteriorly (called the prevertebral fascia) **
• 7. The prevertebral fascia, which covers the vertebrae anteriorly.

• of considerable surgical interest because of the structures related to it.
• An infection with pus located posterior to the prevertebral fascia may perforate this layer and enter the retropharyngeal space.
• This produces a retropharyngeal abscess, which causes difficulty in swallowing and speaking.
• Infections in this space may also extend inferiorly into the superior mediastinum.

• The pharyngeal constrictor muscles have these characteristics:
• 1- They attach anteriorly to bones and ligaments related to the oral and nasal cavities and to the larynx.
• 2- Posteriorly the paired muscles are joined by the pharyngeal raphe (see figure 2 below).
• 3- They overlap each other.
• 4- They constrict the pharyngeal cavity. They contract voluntarily.
• 5- In swallowing they contract sequentially.
• 6- They are innervated by branchial motor fibers of XI via X. These are fibers of CN XI but they course with vagus (CN X).
• 

pterygomandibular raphe

the hyoid bone and the stylohyoid ligament

the thyroid and cricoid cartilages

• The longitudinal muscles are named according to their attachments:
• •Stylopharyngeus (attaches to the styloid process),
• •Palatopharyngeal (attaches to the soft palate),
• •Salpingopharyngeus ( attaches to the auditory tube- “salpinx” in Greek means tube ).
• They descend from their sites of origin and attach into the pharyngeal wall.
• The function of the longitudinal muscles is to elevate the pharyngeal wall during the swallowing process.
• Innervation:
• Palatopharyngeus and salpingopharyngeus by branchial motor fibers of XI coursing with the vagus nerve (CN X)
• The stylopharyngeus by glossopharyngeal nerve (IX)
• The muscles of the pharynx act together during the process of deglutition-
• 

• supplied by branches of the external carotid artery, specifically by:
• 1.The ascending pharyngeal a.,
• 2.Branches of facial a. and
• 3.Branches of lingual a.

branches originating in the thyrocervical trunk (a branch of subclavian a.).

• posterior to the apertures of the nasal cavities and above the soft palate. Most superiorly is the pharyngeal tonsil: a large collection of lymphoid tissue. **
• The following structures are found on each lateral wall:
• •Opening of the auditory tube;
• •Torus tubarius: bulge on the pharyngeal wall formed by the rim of the auditory tube opening;
• •Salpingopharyngeal fold: mucosal elevations and folds post. to the opening of the tube;
• •Pharyngeal recess: a deep area post. to torus tubarius and the salpingopharyngeal fold.
• 

a large collection of lymphoid tissue

bulge on the pharyngeal wall formed by the rim of the auditory tube opening;

mucosal elevations and folds post. to the opening of the tube;

deep area post. to torus tubarius and the salpingopharyngeal fold.

Enlargement of the pharyngeal tonsils, also referred to as the adenoids, can obstruct airflow through the nasopharynx as well as obstruct air exchange between the nasopharynx and middle ear cavity by blocking the opening of the auditory tube.

Infection spreading from the nasopharynx to the middle ear or tympanic cavity causes otitis media (middle ear infection) which may result in temporary or permanent hearing loss.

• posterior to the oral cavity, inferior to the soft palate and above the epiglottis. The anterior wall is the posterior third of the tongue, containing the lingual tonsil: a large collection of lymphoid tissue.
• The following structures are found on each lateral wall:
• •Palatoglossal arch: boundary between the oral cavity and the oropharynx;
• •Palatopharyngeal arch: posterior and medial to the palatoglossal arch;
• •Palatine tonsil: a large collection of lymphoid tissue in the tonsillar fossa or bed.
• The palatine tonsils are visible through the oral cavity
• .

• posterior to the larynx, extending from the epiglottis to the cricoid cartilage where it becomes continuous with the esophagus.
• The laryngopharynx is at the C4-C6 level.
• It communicates with the larynx through the auditus or inlet of the larynx.
• 

• small depression of the laryngopharyngeal cavity on each side of the inlet of the larynx.
• The branches of the internal laryngeal and recurrent laryngeal nerves lie deep to the mucous of the piriform recess.
• ** CLINICAL NOTE: Foreign bodies (chicken bones, safety pins etc.) entering the pharynx may become lodged in the piriform recess. If sharp, they may pierce the mucous membrane and injure the internal laryngeal nerve. This may result in anesthesia of the laryngeal mucous membrane as far inferiorly as the vocal cords. Similarly, the nerve may be injured if the instrument used to remove the foreign object accidentally pierces through the mucous membrane.

• The palatine, lingual and pharyngeal tonsils form an incomplete circular band of lymphoid tissue around the superior part of the pharynx that is called the tonsillar ring or Waldeyer’s ring.
• Some textbooks describe another tonsil called the “tubal tonsil” which is a collection of lymphoid tissue next to the opening of the auditory tube.
• It is also considered part of the tonsillar ring.

• CN V2 (SA) (nasopharynx)
• CN IX (VA) (oropharynx)
• CN X (VA) laryngopharynx).

• VE para-post from V2 (nasopharynx)
• VE para-pre from CN X (oropharynx)
• VE para-pre from CN X (laryngopharynx).

• pterygopalatine ganglion
• pharyngeal plexus
• VE para-post from V2 (nasopharynx)
• VE para-pre from CN X (oropharynx)
• VE para-pre from CN X (laryngopharynx).
• CN V2 (SA) (nasopharynx)
• CN IX (VA) (oropharynx)
• CN X (VA) laryngopharynx).

• supplies the internal aspect of the superior nasopharynx:
• VE para-post fibers to mucosal glands
• SA fibers to mucosa
• VE symp-post fibers to the blood vessels.

• formed by fibers from CN IX, X, XI-via X and sympathetic fibers. Specifically:
• • CN IX supplies VA fibers to the nasopharynx and oropharynx;
• • CN X supplies VA fibers to the laryngopharynx and VE fibers (para/pre) to mucosal glands;
• • CN XI - via X supplies branchial motor (SVE) fibers to all pharyngeal muscles (except stylopharyngeus which is supplied by IX;
• • VE Symp/post fibers supply blood vessels.

• • VA fibers from CN IX to nasopharynx and oropharynx;
• • VA fibers from X to laryngopharynx;
• • VE fibers from X (para/pre) to mucosal glands;
• • VE fibers symp/post to blood vessels;
• • SVE fibers from XI via X to pharyngeal muscles (except stylopharyngeus).
• Note that the SVE fibers from IX to stylopharyngeus are not considered part of the plexus.

• two uppermost parts of the respiratory tract and contain olfactory receptors.
• The anterior apertures of the nasal cavities are the nares, which open to the outside.
• The posterior apertures are the choanae, which open into the nasopharynx.

anterior apertures of nasal cavity

posterior apertures of nasal cavity that opens into nasopharynx

separates nasal cavities from oral cavity

parts of the frontal, ethmoid and sphenoid bones.

• separate nasal cavities
• The medial wall of each nasal cavity is the mucosa-covered surface of the nasal septum.
• The nasal septum consists of:
• •The septal cartilage
• •The vomer
• •The perpendicular plate of the ethmoid bone.
• The nasal septum has relationships with:
• •the palatine and maxillary bones,
• •the nasal and frontal bones and
• •the sphenoid bone.

• branches of the maxillary a. (a branch of the ECA) and the ophthalmic a. (a branch of the ICA).
• The septal branch of the anterior ethmoidal a. and the septal branch of the posterior ethmoidal a. are branches of the ophthalmic a.
• The terminal part of the greater palatine a. and the septal branch of the sphenopalatine a. are branches of the maxillary a.
• These vessels anastomose extensively, specially in the anterior region of the septum.
• 

• (nosebleed) is relatively common because of the richness of blood supply to the nasal mucosa.
• In most cases the cause is trauma and the bleeding is located in the anterior third of the nose, and results from the rupture of arteries particularly at the site of anastomosis of the sphenopalatine and greater palatine arteries.
• Epistaxis can also be associated with infection and hypertension.

• •The olfactory nerve for olfaction;
• •Branches of V1 and V2 for sensation;
• •VE-Para/post fibers from the pterygopalatine ganglion for secretomotor innervation of mucous glands.
• •VE-Symp/post fibers for regulation of blood flow.
• 

• The superior, middle and inferior conchae form the lateral wall of each of the nasal cavities.
• They separate each cavity into four air channels: an spheno-ethmoidal recess and a superior, middle and inferior meatus.
• 

• The following structures open and drain into the nasal cavities:
• •frontal sinuses
• •maxillary sinuses
• •ethmoidal sinuses
• •sphenoidal sinuses
• •frontonasal ducts
• •nasolacrimal ducts
• Since paranasal sinuses drain into the nasal cavities, here is a brief description of the sinuses and related relevant information.

• There are four pairs of paranasal sinuses, each named according to the bone where it is found
• They share the following characteristics:
• •They all open into the nasal cavities,
• •They are all innervated by the trigeminal nerve,
• •They are all lined by respiratory mucosa which secretes mucus.
• Except for the ethmoidal cells, each paranasal sinus is, in most cases, one single cavity.
• 

• three clusters (with a variable number) of small cavities.
• They are named: anterior, middle and posterior ethmoid cells based on the location of their aperture into the lateral wall of the nasal cavities.
• The paranasal sinuses vary in size and form in different people.
• Most of the sinuses are rudimentary absent in the newborn.
• The sinuses enlarge during childhood.

• most involved in infection probably because its aperture is located superior to the floor of the sinus, a poor location for its natural drainage.
• In addition when the mucous membrane of the sinus is congested, the aperture of the sinus may be blocked.

• Infection may spread from the nasal cavities to the paranasal sinuses, producing inflammation and swelling of the mucosa in the sinuses (sinusitis) and local pain.
• Sometimes several sinuses are inflamed (pansinusitis) and the swelling of the mucosa may result in blockage of one or more openings of the sinuses into the nasal cavities.

(branches of V2) supply both the maxillary teeth and the mucous membrane of the maxillary sinus, inflammation of the mucosa of the sinus is often accompanied by the sensation of toothache.

• The posterior ethmoidal air cells open into the lateral wall of the superior meatus
• The sphenoid sinus opens onto the posterior roof of the nasal cavity, into an area called the sphenoethmoidal recess (indicated by a rod in this figure).
• 

• These structures are found in the middle ematus area:
• 1. The ethmoidal bulla is an elevation of the lateral wall of the middle meatus. This is formed by the underlying middle ethmoidal cells.
• 2. The hiatus semilunaris is a curved gutter inferior to the ethmoidal bulla.
• 3. The anterior end of the hiatus forms a channel called the ethmoidal infundibulum.
• 

• elevation of the lateral wall of the middle meatus.
• This is formed by the underlying middle ethmoidal cells.
• The middle ethmoidal air cells open into the ethmoidal bulla

• curved gutter inferior to the ethmoidal bulla.
• maxillary sinus opens into the hiatus semilunaris

• The anterior end of the hiatus forms a channel called the ethmoidal infundibulum.
• anterior ethmoidal air cells and the frontal sinus open into the ethmoidal infundibulum. A rod indicates the opening.

• opens into the inferior meatus.
• It drains tears from the eyes into the nasal cavity.

opening for the sphenoid sinus

opening for the posterior ethmoidal air cells

opening for the middle ethmoidal air cells

opening for the anterior ethmoidal air cells and the frontal sinus

opening for the maxillary sinus

opening for the nasolacrimal duct (or canal)

• supplied by branches of the ICA and branches of the ECA.
• 

• Like the septum, the nasal wall is innervated by:
• •The olfactory nerve for olfaction;
• •Branches of V1 and V2 for sensation;
• •VE-Para/post fibers from the pterygopalatine ganglion for secretomotor innervation of mucous glands.
• •VE-Symp/post fibers for regulation of blood flow.
• 

• Deglutition (swallowing) occurs in three stages:
• 1.The first stage is voluntary. Food is pushed from the mouth into the oropharynx by movements of the muscles of the tongue and soft palate.
• 2.The second stage is involuntary. The soft palate is elevated sealing off the nasopharynx. The oropharynx and laryngopharynx receive the food as the suprahyoid muscles and the longitudinal pharyngeal muscles contract, elevating the pharynx.
• 3.The third stage is also involuntary. Sequential contraction of all three pharyngeal constrictor muscles forces the food inferiorly into the esophagus.