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

fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. ...

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 medial pterygoid muscle and the medial surface of the

ramus of the mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

. The pterygomandibular space is one of the four compartments of the masticator space.

Location and structure

Anatomic boundaries

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

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 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 a ...

, * the inferior alveolar artery 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 th ...

Clinical relevance

The pterygomandibular space is the area where

local anesthetic A local anesthetic (LA) is a medication that causes absence of all sensation (including pain) in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sensati ...

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 (, "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. The term ...

micro-organisms from the mouth may be seeded into the pterygomandibular space during this injection and cause a needle tract infection 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 (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 ta ...

(which gives the motor supply to the muscles of facial expression) run through the substance of the parotid gland and so this is manifest as a transient facial palsy. 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 reas ...

, e.g. of a maxillary

wisdom tooth The third molar, commonly called wisdom tooth, is the most posterior of the three molars in each quadrant of the human dentition. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs between late teens a ...

. 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 ...

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

erythema Erythema (, ) 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 associated with pathology inc ...

(redness) of the anterior tonsillar pillar (the Palatoglossal arch) and deviation of the

uvula The uvula (: uvulas or uvulae), also known as the palatine uvula or staphyle, 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 fi ...

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 wit ...

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

References