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Posterior Superior Alveolar Nerve

nervus alveolaris superior posterior

The posterior superior alveolar nerve is a branch of the maxillary nerve (V2) that arises from the pterygopalatine fossa before the nerve enters the infraorbital groove. It descends on the posterior wall of the maxillary sinus and enters small foramina in the posterolateral maxillary wall to innervate the upper molar teeth and their buccal gingiva, the upper molar roots, and the posterior wall and floor of the maxillary sinus.

Region: Head & Skull

Clinical Relevance

Clinical Notes

The posterior superior alveolar nerve block is a common technique in dental anaesthesia for maxillary molar procedures, injected at the posterior maxillary tuberosity to anaesthetise the upper molars and posterior buccal gingiva. The nerve runs in a plexus within the posterior sinus wall, making it relevant during Caldwell-Luc procedures and in the treatment of recurrent upper molar infections that may spread to the maxillary sinus via periapical abscess disrupting the nerve's bony canal. The maxillary sinus wall surgery risks injury to this nerve.

Pathology

Common Injuries & Conditions

Posterior Superior Alveolar Nerve Block Haematoma

The posterior superior alveolar nerve block can lacerate the pterygoid venous plexus with the injecting needle, causing a rapid intraoral pterygomandibular haematoma that produces trismus and swelling, managed with ice, analgesics, and observation for infection.