The perpendicular or nasal portion ([Fig. 33], b) of the palatine is thin and irregularly quadrilateral in form. It is attached by its cranial two-thirds to the dorsal surface of the horizontal portion. The outer surface is concave and looks into the orbital fossa. The inner surface is convex and looks into the nasal cavity.
The perpendicular portion is marked by two foramina just craniad of the middle. The larger dorsal oval foramen is the sphenopalatine foramen (e). The smaller ventral foramen is the caudal opening of the posterior palatine canal (f). From this opening the canal passes craniomediad, lying in the substance of the palatine bone; it opens on the ventral surface of the horizontal portion at the small openings previously described ([Fig. 41], q).
By its cranial margin it articulates with the lachrymal bone. By its dorsal margin it articulates craniad with the orbital plate of the frontal: with the lamina papyracea at its middle, and with the body of the presphenoid caudad. The caudal half of the dorsal margin is partially divided into two lamellæ with a rough surface between them: this rough surface lies against the ventral surface of the presphenoid. The caudal margin articulates with the pterygoid portion of the sphenoid.
Lachrymal Bone. Os lachrymale
([Fig. 34]; [Fig. 39], 10).—The lachrymal bone is a thin pentagonal scale of bone filling the interval between the horizontal plate of the palatine, the maxillary, and the orbital plate of the frontal. Its outer surface looks into the orbit, its inner surface into the nasal cavity.
Fig. 34.—Lachrymal Bone of Left Side, External Surface.
[Fig. 35].—Malar Bone of Right Side, Lateral Surface.
![[Fig. 35]](#3418956513767812439_illo046blg.jpg.id-1223687055967560918.wrap-0.html.html){kind=link}
Fig. 34.—a, notch forming the beginning of the lachrymal canal.