The parapharyngeal space (also termed the lateral pharyngeal space), is a
potential space in the head and the neck. It has clinical importance in
otolaryngology due to parapharyngeal space tumours and
parapharyngeal abscess developing in this area. It is also a key anatomic landmark for localizing disease processes in the surrounding spaces of the neck; the direction of its displacement indirectly reflects the site of origin for masses or infection in adjacent areas, and consequently their appropriate differential diagnosis.
Anatomical boundaries
The parapharyngeal space is shaped like an inverted pyramid. Lateral and inferior to the parapharyngeal space is the
carotid sheath
The carotid sheath is a condensation of the deep cervical fascia enveloping multiple vital neurovascular structures of the neck, including the common and internal carotid arteries, the internal jugular vein, the vagus nerve (CN X), and ansa c ...
, containing the
internal carotid artery
The internal carotid artery is an artery in the neck which supplies the anterior cerebral artery, anterior and middle cerebral artery, middle cerebral circulation.
In human anatomy, the internal and external carotid artery, external carotid ari ...
and
cranial nerves
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...
IX,
X and
XI. Behind both the parapharyngeal space and carotid space lies the
retropharyngeal space, and deep to this a potential space known as the
danger space. The danger space serves as an important pathway for complicated infections of the posterior pharynx to enter the chest and spinal column. Anterior to the parapharyngeal space is the
masticator space which contains the lower dental row, muscles of mastication, the
inferior alveolar nerve as well as branches of
cranial nerve V. Lateral to the parapharyngeal space lies the
parotid space, which contains the parotid gland, the
external carotid artery and
cranial nerve VII.
Although initial evaluation is typically by physical exam and
endoscopy
An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are insert ...
, follow up with
CT and
MRI usually is needed if surgical intervention is planned.
Bony anatomy around the space includes the skull base superiorly, and the
greater cornu (or greater horns) of the hyoid bone the apex, inferiorly. The superior aspect is the
base of skull, namely the
sphenoid and
temporal bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...
s. This area includes the
jugular and
hypoglossal canal and the
foramen lacerum (through which the internal carotid artery passes superiorly across).
The medial aspect is made up of the
pharynx
The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...
. Anteriorly it is bordered by the
pterygomandibular raphe. Posteriorly it is bordered by carotid sheath posteriolaterally and the retropharyngeal space posteriomedially. The lateral aspect is more involved, and is bordered by the ramus of the mandible, the deep lobe of the
parotid gland, the
medial pterygoid muscle, and below the level of the mandible, the lateral aspect is bordered by the fascia of the posterior belly of
digastric muscle. These anatomical boundaries make it continuous with the
retropharyngeal space. It also communicates with other cervical and cranial fascial spaces, as well as the
mediastinum
The mediastinum (from ;: mediastina) is the central compartment of the thoracic cavity. Surrounded by loose connective tissue, it is a region that contains vital organs and structures within the thorax, mainly the heart and its vessels, the eso ...
.
Divisions
The parapharyngeal space is divided into 2 parts by the fascial condensation called the aponeurosis of Zuckerkandl and Testut (stylopharyngeal fascia - see diagram),
[ joining the styloid process to the tensor veli palatini. These two compartments are named the pre-styloid and post-styloid (retrostyloid) compartments or spaces. However, some classification schemes call the pre-styloid compartment the parapharyngeal space and the post-styloid compartment the carotid space, which can be a source of confusion.
]
Contents
It includes the maxillary artery
The maxillary artery (eg, internal maxillary artery) supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible.
Structure
The maxillary artery, the larger of the two terminal branches ...
and ascending pharyngeal artery.
Clinical significance
First bite syndrome is a rare complication of a surgery involving the parapharyngeal space, especially removal of the deep lobe of the parotid gland. It is characterized by facial pain after the first bite of each meal, and is thought to be caused by autonomic dysfunction of salivary myoepithelial cells.
References
Bibliography
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{{Authority control
Fascial spaces of the head and neck
Human throat