Maxillary line

The maxillary line is a mucosal projection along the lateral nasal wall corresponding to lacrimomaxillary suture externally. The midportion of the line is called "M point". During endoscopic sinus and orbital procedures the maxillary line and M-point are very important and useful landmarks in particular during an endoscopic dacryocystorhinostomy.

The maxillary line is a curvilinear eminence along the lateral nasal wall that runs from the anterior attachment of the middle turbinate to the root of the inferior turbinate. This line bisects the lacrimal sac. As it mentioned earlier, it corresponds to the lacrimomaxillary suture, so endoscopist would know that posterior to the maxillary line would correspond to the thin lacrimal bone and posterior half of the lacrimal sac.

The M point is approximately 3.9 cm from the nasal sill in women and 4.8 cm in men.