The middle superior alveolar nerve
is a nerve
that drops from the infraorbital portion
of the maxillary nerve
to supply the sinus mucosa
, the roots of the maxillary premolars
, and the mesiobuccal root
of the first maxillary molar.
Approximately 28% of people do not have a middle superior alveolar nerve. In such cases, the anterior superior alveolar nerve innervates the maxillary premolars and the mesiobuccal root of the first maxillary molar.