The pterygomandibular space is a narrow, fascial space of the head and neck located within the infratemporal fossa. It is of significant clinical importance in dentistry and oral surgery, particularly as the target site for the administration of the inferior alveolar nerve block.
Boundaries
The pterygomandibular space is defined by the following anatomical structures:
- Lateral boundary: The medial surface of the ramus of the mandible.
- Medial boundary: The lateral surface of the medial pterygoid muscle.
- Superior boundary: The lateral pterygoid muscle.
- Anterior boundary: The pterygomandibular raphe and the buccinator muscle.
- Posterior boundary: The parotid gland (specifically the deep lobe) and the stylomandibular ligament.
- Inferior boundary: The lower border of the mandible, where the medial pterygoid muscle attaches to the pterygoid tuberosity.
Contents
The space contains several vital neurovascular structures and connective tissues:
- Inferior alveolar nerve: A branch of the mandibular nerve (V3) that provides sensation to the mandibular teeth.
- Inferior alveolar artery and vein: Vessels that accompany the nerve through the mandibular foramen.
- Lingual nerve: Provides sensory innervation to the anterior two-thirds of the tongue and the lingual gingiva.
- Sphenomandibular ligament: A flat, thin band that attaches the spine of the sphenoid bone to the lingula of the mandible.
- Adipose tissue: Loose connective tissue and fat that fill the remainder of the space.
Clinical Significance
The pterygomandibular space is the primary anatomical landmark for performing an inferior alveolar nerve block (IANB), the most common local anesthetic technique used for dental procedures on the mandibular teeth. The needle is inserted through the buccinator muscle into this space to deposit anesthetic solution near the mandibular foramen.
Additionally, the space is a potential site for the spread of odontogenic infections. Infections originating from the mandibular second or third molars can penetrate the thin lingual cortical plate below the mylohyoid line, potentially leading to a pterygomandibular space abscess. Because this space communicates with other fascial compartments, such as the submandibular, parapharyngeal, and infratemporal spaces, infections can spread rapidly throughout the deep neck structures.
