Maxillary tuberosity

Topography and adjacent structures

The maxillary tuberosity participates in forming the boundaries of several regions of the facial skeleton:

• Maxillary sinus (sinus maxillaris): the tuberosity forms its posterolateral wall. Superiorly, this wall is bounded by the inferior orbital fissure, posteriorly it reaches the pterygopalatine fossa, and its posterosuperior angle closely approaches the ethmoidal air cells and the sphenoid sinus.
• Infratemporal fossa (fossa infratemporalis): the tuberosity serves as its anterior boundary.
• Intermaxillary fascial space (according to N.I. Pirogov): the tuberosity bounds this deep facial region anteriorly. Superiorly are the body and greater wing of the sphenoid bone, medially is the pterygoid process, laterally is the ramus of the mandible, and inferiorly is the medial pterygoid muscle.

Structure and muscular apparatus

On the surface of the maxillary tuberosity are 3–4 alveolar foramina (foramina alveolaria). They lead into intraosseous alveolar canals (canales alveolares) directed toward the roots of the molars and premolars.

The head of the lateral pterygoid muscle (m. pterygoideus lateralis) attaches to the tuberosity.

Blood supply and innervation

Structures supplying blood and innervation to the upper posterior teeth pass through the foramina on the maxillary tuberosity:

• Posterior superior alveolar arteries (aa. alveolares superiores posteriores): arise from 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 molars. They are accompanied by veins of the same name.
• Posterior superior alveolar nerves (nn. alveolares superiores posteriores): branch off from the maxillary nerve, the V2 division of the trigeminal nerve, in the pterygopalatine fossa.

In the region of the tuberosity, the fibers of the posterior superior alveolar nerves divide into two groups:

1. Extraosseous part — does not enter the bone, but descends along the outer 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.
2. Intraosseous part — enters the posterior superior alveolar canals piercing the tuberosity. It innervates the mucous membrane of the maxillary sinus, the tooth sockets, the periodontal ligaments, and the pulp tissue of all three maxillary molars. In some patients, the posterior superior alveolar nerves do not innervate the mesiobuccal root of the first molar.

Clinical significance

The maxillary second and third molars are the primary odontogenic sources of inflammatory processes.

• Diagnosis of abscesses and phlegmons: in infratemporal fossa phlegmon, the infiltrate is palpated directly posterior to the maxillary tuberosity. Upon intraoral examination, pain increases sharply when pressure is applied to the tuber maxillae region.
• Differential diagnosis: lesions of the pterygopalatine fossa do not present with facial asymmetry. In infratemporal fossa phlegmon, whose anterior boundary is the tuberosity, collateral edema in the buccal and infraorbital regions and a hourglass-shaped swelling of the soft tissues of the temporal region are observed. Inflammation easily spreads from the infratemporal fossa to the temporal region.

Class and exam questions

What else to study on this topic

• Maxillary bone (Maxilla) and its surfaces
• Infratemporal fossa (Fossa infratemporalis)
• Maxillary nerve (n. maxillaris) and its branches
• Maxillary artery (a. maxillaris)
• Odontogenic phlegmons of the maxillofacial region

Other topics in the "Anatomical Structures" section

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