fluid to well-localized lymph nodes. These nodes are often the first site at which pathologic processes manifest themselves. Because the nodes draining the face and dental arches are located near the mandible, they will be discussed in the mandibular anatomy section.

Nerves

Maxillary innervation derives from the maxillary nerve (1), one of the three major branches of the trigeminal, or fifth, cranial nerve (2). The maxillary nerve, whose pathways closely follow those of the maxillary artery, has three main primarily sensory branches : the pterygopalatine nerve (3), the infraorbital nerve (4), and the zygomatic nerve (5). Because the zygomatic nerve passes superiorly well out of involvement in most dental procedures, it will be ignored in this discussion.

Nerves serving potential maxillary implant sites derive from the pterygopalatine and infraorbital nerves. The dental arch itself is supplied by two or three major branches of the infraorbital nerve: the posterior superior alveolar nerve (6) , the middle superior alveolar nerve (7), and the anterior superior alveolar nerve (8).

The infraorbital nerve gives off the posterior superior alveolar artery (6) in the infratemporal fossa, behind the maxillary tuberosity. The nerve angles downward anteriorly, branching within the bone behind the sinus to form twigs that supply the posterior alveolar process.

The middle superior alveolar nerve (7) arises from the infra-orbital nerve in about 60% of the cases. When present, the middle superior alveolar nerve is given off in the infraorbital sulcus region and travels within the roof of the maxillary sinus, following the bony framework of the sinus vault as it curves downward to reach the alveolar process. If this nerve is absent, fibers from the posterior and anterior superior alveolar nerves extend into the region.

Prior to leaving the infraorbital canal and passing into the soft tissues of the upper face, the infraorbital nerve gives off with-in bone one or more branches the anterior superior alveolar nerve(s) (8) — which descend in front of the sinus and supply the teeth, their supporting tissues, and the labial surface of the gingiva from the midline to the canine region.

The palatal surface of the ridge, specifically the small area of mucosa behind the incisors, is supplied by the nasopalatine nerve

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