Topography and Adjacent Structures
The maxillary tuberosity contributes to the boundaries of several facial skull regions:
- Maxillary sinus (sinus maxillaris): the tuberosity forms its posterolateral wall. Superiorly, this wall is bounded by the inferior orbital fissure; posteriorly, it extends to the pterygopalatine fossa, and its posterosuperior angle lies in close proximity to the ethmoidal air cells and the sphenoid sinus.
- Infratemporal fossa (fossa infratemporalis): the tuberosity forms its anterior boundary.
- Intermaxillary fascial space: the tuberosity forms the anterior border of this deep facial space. The body and greater wing of the sphenoid bone lie superiorly, the pterygoid process medially, the ramus of the mandible laterally, and the medial pterygoid muscle inferiorly.
Structure and Muscular Attachments
The surface of the maxillary tuberosity features 3 to 4 alveolar foramina (foramina alveolaria). These lead into intraosseous alveolar canals (canales alveolares), which travel toward the roots of the molar and premolar teeth.
The head of the lateral pterygoid muscle (m. pterygoideus lateralis) attaches to the tuberosity.
Blood Supply and Innervation
The foramina on the maxillary tuberosity transmit neurovascular structures supplying the posterior superior teeth:
- Posterior superior alveolar arteries (aa. alveolares superiores posteriores): branches of the third (pterygopalatine) part of the maxillary artery. They enter the tuberosity and give off dental (rr. dentales) and peridental branches (rr. peridentales) to the large molar teeth, accompanied by corresponding veins.
- Posterior superior alveolar nerves (nn. alveolares superiores posteriores): branches of the maxillary nerve (CN V2) originating in the pterygopalatine fossa.
In the region of the tuberosity, the fibers of the posterior superior alveolar nerves divide into two groups:
- Extraosseous branch — remains outside the bone, descending along the external surface of the tuberosity toward the alveolar process. It innervates the periosteum of the maxilla, the buccal mucosa, and the vestibular gingiva at the level of the premolars and molars.
- Intraosseous branches — enter the posterior superior alveolar canals piercing the tuberosity. They innervate the Schneiderian membrane of the maxillary sinus, dental alveoli, periodontal ligaments, and pulp tissues of all three maxillary molars. In some individuals, these nerves may not supply the mesiobuccal root of the first molar.
Clinical Significance
The maxillary second and third molars are primary odontogenic sources of inflammatory processes.
- Diagnosis of abscesses and phlegmons: In infratemporal fossa phlegmon, inflammatory infiltration is palpable directly posterior to the maxillary tuberosity. During intraoral examination, pressure applied to the tuber maxillae sharply exacerbates pain.
- Differential diagnosis: In isolated pathology of the pterygopalatine fossa, external facial asymmetry may not be apparent. Conversely, infratemporal fossa phlegmons (bounded anteriorly by the tuberosity) present with collateral edema extending to the buccal and infraorbital regions, along with an hourglass-shaped swelling of the temporal soft tissues. Inflammation can easily spread from the infratemporal fossa into the temporal region.