The maxilla (maxilla) or upper jaw is a paired bone. It takes part in the formation of the orbit, nose and septa between the cavities of the nose and mouth, and participates in the process of mastication. The maxilla consists  of a body and four processes (frontal, alveolar, palatine, and zygomatic).

The body of maxilla (corpus maxillae)has the maxillary sinus, and four surfaces (anterior, infratemporal, nasal, and orbital).

Maxillary sinus is an air space coverd by mucosal epithelium. It is the biggest sinus, which has a wide opening on the medial wall called the maxillary hiatus (hiatus maxillaris)which is enveloped by the:

  • Inferior nasal concha and uncinate process which covers from the inferior side
  • Ethmoid bulla which covers from the superior side
  • Palatine bone which covers from the posterior side.

The maxillary sinus communicates with the nasal cavity by the semilunar hiatus (hiatus semilunaris).

Anterior surface (facies anterior) has the:

  • Canine fossa (fossa canina) which lies above and lateral to the canine tooth. It is the depression in the anterior wall of the maxilla. The anterior superior alveolar vessels and nerves run between the fossa and maxillary sinus in the bony wall.
  • Infraorbital margin (margo infraorbitalis).
  • Infraorbital foramen (foramen infraorbitale) through which the infraorbital nerve and vessels leave the orbit.
  • Nasal notch (incisura nasalis) with the anterior nasal spine (spina nasalis anterior).

nfratemporal surface (facies infratemporalis) has the:

  • Maxillary tuberosity (tuber maxillae) with the:
  • Alveolar foramina (foramina alveolares) which continue as:
  • Alveolar canals (canales alveolares) which transmit nerves and vessels that pass through the thick maxillary wall.

Nasal surface (facies nasalis) has the:

  • Conchal crest (crista conchalis) which is seen on palatine process as well.
  • Lacrimal groove (sulcus lacrimalis) which empties into the nasolacrimal canal (canalis nasolacrimalis) which is found on the lacrimal bone and serves as the communication site between the orbit and the nasal cavity.

Orbital surface (facies orbitalis) is triangular. It has the infraorbital groove (sulcus infraorbitalis) which originates near the posterior border of the orbital surface and is converted anteriorly into the infraorbital canal (canalis infraorbitalis)which opens into the anterior surface of the maxilla.

Four processes are as follows:

Frontal process (processus frontalis) projects the:

  • Anterior lacrimal crest (crista lacrimalis anterior).
  • Ethmoidal crest (crista ethmoidalis) for attachment of the middle nasal concha.
  • Lacrimal notch (incisura lacrimalis).

Alveolar process (processus alveolaris) contains the:

  • Alveolar arch (arcus alveolaris) with the dental alveoli (alveoli dentales) which are separated by the interradicular septa (septa interra- dicularia)
  • Interalveolar septa (septa interalveolaria)
  • Alveolar yokes (juga alveolaria)

Palatine process (processus palatinus) forms the roof of the mouth and the floor of the nostril. It has the:

  • Incisive canal (canalis incisivus)
  • Nasal crest (crista nasalis)
  • Palatine grooves (sulci palatini)

Zygomatic process (processus zygomaticus) joins with the zygomatic bone.