The pterygomandibular space is a fascial space of the head and neck (sometimes also termed

fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...

l spaces or tissue spaces). It is a

potential space In anatomy, a potential space is a space between two adjacent structures that are normally pressed together (directly apposed). Many anatomic spaces are potential spaces, which means that they are potential rather than realized (with their realiz ...

in the head and is paired on each side. It is located between the

lateral pterygoid muscle The lateral pterygoid muscle (or external pterygoid muscle) is a muscle of mastication. It has two heads. It lies superior to the medial pterygoid muscle. It is supplied by pterygoid branches of the maxillary artery, and the lateral pterygoid ner ...

and the medial surface of the

ramus of the mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

. The pterygomandibular space is one of the four

compartment Compartment may refer to: Biology * Compartment (anatomy), a space of connective tissue between muscles * Compartment (chemistry), in which different parts of the same protein serves different functions * Compartment (development), fields of cells ...

s of the

masticator space Fascial spaces (also termed fascial tissue spaces or tissue spaces) are potential spaces that exist between the fasciae and underlying organs and other tissues. In health, these spaces do not exist; they are only created by pathology, e.g. the spr ...

Location and structure

Anatomic boundaries

The boundaries of each pterygomandibular space are: * the posterior border of the

buccal space The buccal space (also termed the buccinator space) is a fascial space of the head and neck (sometimes also termed fascial tissue spaces or tissue spaces). It is a potential space in the cheek, and is paired on each side. The buccal space is supe ...

anteriorly * the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the man ...

posteriorly * the lateral pterygoid muscle superiorly * the inferior border of the mandible (lingual surface) inferiorly * the medial pterygoid muscle medially (the space is superficial to medial pterygoid) * the ascending ramus of the mandible laterally (the space is deep to the ramus of the mandible)

Communications

The communications of each pterygomandibular space are: * to the buccal space anteriorly * to the

lateral pharyngeal space 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. ...

and peritonsillar space medially (around the medial pterygoid muscle). * to the submasseteric space laterally (around the ramus of the mandible) * to the parotid space posteriorly * to the deep temporal/infratemporal space superiorly

In health, the space contains: * the

mandibular division of the trigeminal nerve In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only aff ...

, * the

inferior alveolar artery The inferior alveolar artery (inferior dental artery) is an artery of the face. It is a branch of the first portion of the maxillary artery. Structure It descends with the inferior alveolar nerve to the mandibular foramen on the medial surface of ...

and vein, * the

sphenomandibular ligament The sphenomandibular ligament (internal lateral ligament) is one of the three ligaments of the temporomandibular joint. It is situated medially to - and generally separate from - the articular capsule of the joint. Superiorly, it is attached to the ...

Clinical relevance

The pterygomandibular space is the area where

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...

solution is deposited during an inferior alveolar nerve block, a common procedure used to anesthetize the distribution of the inferior alveolar nerve. Rarely,

pathogenic In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

micro-organisms from the mouth may be seeded into the pterygomandibular space during this injection and cause a

needle tract infection An injection (often and usually referred to as a "shot" in US English, a "jab" in UK English, or a "jag" in Scottish English and Scots) is the act of administering a liquid, especially a drug, into a person's body using a needle (usually a hyp ...

of the space. It is also occasionally reported that the needle breaks off and is retained in the pterygomandibular space during this injection. Minor oral surgery is then required to remove the fractured needle. Due to its high vascularity, injections into the pterygomandibular space carry a high risk of

intravascular injection The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

(injecting into a blood vessel). Another possible complication of an inferior alveolar nerve block occurs when the needle is placed too deep, passing through the pterygomandibular space and into the parotid gland behind. Branches of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...

(which gives the motor supply to the

muscles of facial expression The facial muscles are a group of striated skeletal muscles supplied by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, al ...

) run through the substance of the parotid gland and so this is manifest as a transient

facial palsy Facial nerve paralysis is a common problem that involves the paralysis of any structures innervated by the facial nerve. The pathway of the facial nerve is long and relatively convoluted, so there are a number of causes that may result in facial ...

. The pterygomandibular space is one of the possible spaces into which a tooth may be displaced into during

dental extraction A dental extraction (also referred to as tooth extraction, exodontia, exodontics, or informally, tooth pulling) is the removal of teeth from the dental alveolus (socket) in the alveolar bone. Extractions are performed for a wide variety of reason ...

, e.g. of a maxillary

wisdom tooth A third molar, commonly called wisdom tooth, is one of the three molars per quadrant of the human dentition. It is the most posterior of the three. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs betwe ...

. A

mandibular fracture Mandibular fracture, also known as fracture of the jaw, is a break through the mandibular bone. In about 60% of cases the break occurs in two places. It may result in a decreased ability to fully open the mouth. Often the teeth will not feel pr ...

in the angle region may also be the cause of a pterygomandibular space infection. The signs and symptoms of an isolated pterygomandiublar infection may include

trismus Trismus, commonly called ''lockjaw'' as associated with tetanus, is a condition of limited jaw mobility. It may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than perma ...

(difficulty opening the mouth), however there is not usually any externally visible facial swelling. Intra-orally, there may be swelling and

erythema Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not assoc ...

(redness) of the anterior tonsillar pillar (the

Palatoglossal arch The palatoglossal arch (glossopalatine arch, anterior pillar of fauces) on either side runs downward, lateral (to the side), and forward to the side of the base of the tongue, and is formed by the projection of the glossopalatine muscle with its c ...

) and deviation of the

uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers. It also conta ...

to the unaffected side. The airway may be compressed. Treatment is by surgical

incision and drainage Incision and drainage (I&D), also known as clinical lancing, are minor surgical procedures to release pus or pressure built up under the skin, such as from an abscess, boil, or infected paranasal sinus. It is performed by treating the area with an ...

, and the incision may be placed inside the mouth or two incisions may be used, one inside the mouth and one outside.

Odontogenic infections

Odontogenic infection An odontogenic infection is an infection that originates within a tooth or in the closely surrounding tissues. The term is derived from '' odonto-'' (Ancient Greek: , – 'tooth') and '' -genic'' (Ancient Greek: , ; – 'birth'). The most common ...

s may spread to involve the pterygomandibular space, and the most common teeth responsible for this are the mandibular second and third molar teeth.

References