Nerve · Head

Middle superior alveolar nerve

Nervus alveolaris superior medius

The smallest and least reliable of the three nerves serving the upper teeth, supplying the premolars and often the front root of the first molar. It leaves the infraorbital nerve in the groove or canal in the orbital floor and descends in the outer wall of the maxillary sinus to join the superior dental plexus. What sets it apart is that it frequently does not exist: in many people no separate middle branch forms, and the premolars are covered instead by the anterior and posterior alveolar nerves extending to meet one another. That variability is ordinary anatomy rather than an abnormality, and it is the reason the dental supply is better pictured as one shared network than as three fixed territories.