Constant features of the adult maxillary bone in the site of the premaxillary suture: the sutura notha, Macalister's foramina, Parinaud's canal, and the second angle of the canalis sinuosus of Wood Jones.

Developmental theories regarding the premaxillary (incisive) suture commonly overlook it separates the premaxillary and maxillary parts of the frontal process of maxilla. Thus, one would expect that neurovascular structures within this transitory mesenchymal zone to appear embedded within the adult frontal process of maxilla. The sutura notha (false suture, Weber's sutura longitudinalis imperfecta) is a poorly described, although constantly present, shallow groove in front of the anterior lacrimal crest, being perforated by a row of holes first described, to our knowledge, by Macalister, in 1884. Macalister's foramina should be discriminated anatomically from the accessory infraorbital foramina. Macalister's foramina lead into canals, usually described as vascular, within the frontal process. We demonstrate in cone-beam computed tomography that these canals, which correspond topographically to Parinaud's vascular canal, are connected, usually through a delicate intraosseous network, with Wood Jones' canalis sinuosus (i.e., the ampullar angle of this canal located above the upper canine tooth). As this later carries the anterior superior alveolar nerve and artery, it is reasonable to consider that the canalar network within the frontal process of maxilla could serve for an accessory distribution of that nerve to the nasolacrimal duct, the atrium of the middle nasal meatus, the agger nasi cell, as well as to the infraorbital (prelacrimal) recess of the maxillary sinus.