3. Anatomy of the pharynx.
The pharynx extends from the nasal cavity to the larynx and is arbitrarily
divided into three compartments. The nasopharynx extends from the skull
base to the soft palate. Its function is entirely respiratory, and the
nasopharynx is not considered further in this chapter. The oropharynx is
posterior to the oral cavity and extends from the soft palate to the hyoid
bone. The hypopharynx (laryngopharynx) extends from the hyoid bone to
the cricopharyngeus muscle. The base of the tongue forms the anterior
boundary of the oropharynx. The outline of the surface of the tongue is
nodular because of the presence of lymphoid tissue forming the lingual
tonsils and the circumvallate papillae, which contain taste buds. The
lingual tonsils may hypertrophy and mimic a neoplasm. The epiglottis and
aryepiglottic folds separate the larynx from the oropharynx and the
hypopharynx. The valleculae are two symmetrical pouches formed in the
recess between the base of the tongue and the epiglottis. They are divided
medially by the median glossoepiglottic fold and bounded laterally by the
lateral glossoepiglottic folds. The piriform sinuses are deep, symmetrical,
lateral recesses formed by the protrusion of the larynx into the
hypopharynx.
4. The nasopharynx
The nasopharynx is that part of the pharynx between the posterior
choanae and the lower limit of the soft palate. It communicates anteriorly
with the nasal cavity and inferiorly with the oropharynx. The roof of the
nasopharynx is bound to the inferior surface of the sphenoid and clivus by
the pharyngobasilar fascia. It has the parapharyngeal space and the deep
soft tissues of the infratemporal space laterally. Posteriorly it lies on the
upper cervical vertebrae and longus collis and capitus, and
posterolaterally the styloid muscles separate it from the carotid sheath.
The eustachian tube opens on to the lateral wall of the nasopharynx on
either side, piercing the pharyngobasilar fascia. This opening has a
posterior ridge formed by the cartilaginous end of the tube known as the
torus tubarius. Behind these ridges are the paired lateral pharyngeal
recesses, also known as the fossae of Rosenmüller. The muscular layer of
the nasopharynx is formed by the superior pharyngeal constrictor. The
palatal muscles arise from the base of the skull on either side of the
eustachian tube. The levator veli palatini accompanies the eustachian
tube, piercing the pharyngobasilar fascia before inserting into the
posterior part of the soft palate.
5. The tensor veli palatini runs around the nasopharynx and hooks around the
pterygoid hamulus before inserting into the membranous part of the soft
palate. These muscles, along with those in the palatopharyngeal arch,
elevate the soft palate, closing it against a muscular ridge in the superior
constrictor muscle (known as the Passavant ridge) during deglutition,
thereby isolating the nasopharynx from the oropharynx.
Lymphoid tissue lines the nasopharynx, and this is prominent superiorly
where it forms the adenoids.
The lymphatic drainage of the nasopharynx and related spaces is to the
jugular chain of lymph nodes, especially the jugulodigastric node, which lies
at the angle of the mandible. Spaces related to the nasopharynx
The parapharyngeal space is a slit-like space just lateral to the nasopharynx
extending down from the base of the skull. The space is bounded by the
buccopharyngeal fascia. This fascial plane separates the pharyngeal muscles
from the muscles of mastication (the pterygoids and the deep part of the
temporalis muscle). It is loosely applied to allow movement and contains
branches of the external carotid artery, pharyngeal veins and mandibular
nerve. Posteriorly, it is separated from the carotid sheath by the styloid
process and its muscles, and the deep part of the parotid gland lies laterally.
6. The infratemporal space lies lateral to the nasopharynx and
paranasopharyngeal space behind the posterior wall of the maxilla. It
extends from the base of the skull to the hyoid bone, and contains the
pterygoid muscles. It is continuous superiorly with the temporal fossa
through the gap between the zygomatic arch and the side of the skull.
Medial to this, the roof is formed by the inferior surface of the middle
cranial fossa and is pierced by the foramen ovale and foramen spinosum.
Laterally, the space is bounded by the zygomatic arch, temporalis muscle,
ascending ramus of mandible and its coronoid process. Medially, the
space is limited by the lateral pterygoid plate and nasopharynx. The
space lies anterior to the deep part of the parotid, the styloid process and
its muscles, and the carotid artery and jugular vein. The anteromedial
limit of the infratemporal space is formed by the junction of the lateral
pterygoid plate with the posteromedial limit of the maxilla superiorly and
the posterior border of the perpendicular plate of the palate inferiorly.
The anterior and medial walls of the space meet inferiorly but are
separated superiorly by the pterygomaxillary fissure, where the
pterygoid plates diverge from the posterior wall of the maxilla.
7. The pterygopalatine fossa is a medial depression of the
pterygomaxillary fissure lying just below the apex of the orbit between
the pterygoid process and the posterior maxilla. Its medial margin is the
perpendicular plate of the palatine bone. It is important as it connects
several spaces and may facilitate the spread of pathology between
them. It communicates superiorly with the orbit through the posterior
part of the inferior orbital fissure. The foramen rotundum opens into it
superiorly, connecting it with the middle cranial fossa. Laterally it
communicates freely with the infratemporal fossa. Medially the space
communicates with the nasal cavity via the sphenopalatine foramen in
the perpendicular plate of the palatine bone, and with the oral cavity
through the greater palatine canal, which runs inferiorly between the
palatine bone and the maxilla. The fossa contains the maxillary division
of the fifth cranial nerve, which runs through the foramen rotundum
and into the orbit via the inferior orbital fissure. It also contains the
pterygopalatine segment of the maxillary artery, which makes a
characteristic loop and gives off branches to the middle cranial and
infratemporal fossae and to the nasal cavity, palate and pharynx.
12. 1 – Nasopharynx.
2 - Tensor veli palatini.
3 - Levator veli palatini.
4 - Temporalis muscle
Medial / deep head.
5 - Temporalis muscle
lateral / superficial head.
6 - Coronoid process of mandible.
7 - Lateral pterygoid muscle.
8 - Condylar process of mandible.
11 - Pterygomaxillary fissure.
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65. The oropharynx and laryngopharynx
The oropharynx is the part of the pharynx that extends from the
lower part of the soft palate to the epiglottis. It is continuous
through the posterior fauces with the oral cavity and with the
laryngopharynx below. It is lined by mucosa which is continuous
with that of the oral cavity and nasopharynx. Its submucosal layer
is continuous with the pharyngobasilar fascia above, and its
muscular layer has contributions from the superior constrictor,
some of the tongue muscles, and levator and tensor veli palatini.
The laryngopharynx is the part of the pharynx that lies behind the
larynx. It extends from the level of the epiglottis to the level of C6,
where it continues as the oesophagus. The upper laryngopharynx is
moulded around the proximal part of the larynx, forming two deep
recesses on either side known as the piriform fossae. During
deglutition the epiglottis helps conduct fluid and solid boluses
along the piriform fossae from the oropharynx to the oesophagus,
avoiding the entrance to the larynx.
66. Oropharynx:
The oropharynx lies behind the oral cavity, extending from the uvula to
the level of the hyoid bone. It opens anteriorly, through the isthmus
faucium, into the mouth, while in its lateral wall, between the
Palatoglossal arch and the Palatopharyngeal arch, is the palatine tonsil.[2]
The anterior wall consists of the base of the tongue and the epiglottic
vallecula; the lateral wall is made up of the tonsil, tonsillar fossa, and
tonsillar (faucial) pillars; the superior wall consists of the inferior surface
of the soft palate and the uvula. Because both food and air pass through
the pharynx, a flap of connective tissue called the epiglottis closes over
the glottis when food is swallowed to prevent aspiration. The oropharynx
is lined by non-keratinised squamous stratified epithelium.
The HACEK organisms (Haemophilus, Actinobacillus
actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens,
Kingella) are part of the normal oropharyngeal flora, which grow slowly,
prefer a carbon dioxide-enriched atmosphere, and share an enhanced
capacity to produce endocardial infections, especially in young children.
Fusobacterium is a pathogen.
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103. (Hypopharynx )Laryngopharynx:
The laryngopharynx, (Latin: pars laryngea pharyngis), is the caudal part of the
pharynx; it is the part of the throat that connects to the esophagus. It lies inferior
to the epiglottis and extends to the location where this common pathway diverges
into the respiratory (larynx) and digestive (esophagus) pathways. At that point,
the laryngopharynx is continuous with the esophagus posteriorly. The esophagus
conducts food and fluids to the stomach; air enters the larynx anteriorly. During
swallowing, food has the "right of way", and air passage temporarily stops.
Corresponding roughly to the area located between the 4th and 6th cervical
vertebrae, the superior boundary of the laryngopharynx is at the level of the hyoid
bone. The laryngopharynx includes three major sites: the pyriform sinus,
postcricoid area, and the posterior pharyngeal wall. Like the oropharynx above it,
the laryngopharynx serves as a passageway for food and air and is lined with a
stratified squamous epithelium. It is innervated by the pharyngeal plexus.
The vascular supply to the hypopharynx includes the superior thyroid artery, the
lingual artery and the ascending pharyngeal artery. The primary neural supply is
from both the vagus and glossopharyngeal nerves. The vagus nerve provides a
branch termed "Arnolds Nerve" which also supplies the external auditory canal,
thus hypophayrngeal cancer can result in referred otalgia. This nerve is also
responsible for the ear-cough reflex in which stimulation of the ear canal results in
a person coughing.
108. AP and lateral views of the barium-coated pharynx and
hypopharynx obtained during phonation demonstrates normal
anatomy but also aspiration of barium into the larynx and trachea.