Henry Gray (18251861). Anatomy of the Human Body. 1918.
process, which is directed backward and lateralward from the junction of the two parts, and the orbital and sphenoidal processes, which surmount the vertical part, and are separated by a deep notch, the sphenopalatine notch.
The Horizontal Part (pars horizontalis; horizontal plate) (Figs. 168,169).The horizontal part is quadrilateral, and has two surfaces and four borders.
Surfaces.The superior surface, concave from side to side, forms the back part of the floor of the nasal cavity. The inferior surface, slightly concave and rough, forms, with the corresponding surface of the opposite bone, the posterior fourth of the hard palate. Near its posterior margin may be seen a more or less marked transverse ridge for the attachment of part of the aponeurosis of the Tensor veli palatini.
Borders.The anterior border is serrated, and articulates with the palatine process of the maxilla. The posterior border is concave, free, and serves for the attachment of the soft palate. Its medial end is sharp and pointed, and, when united with that of the opposite bone, forms a projecting process, the posterior nasal spine for the attachment of the Musculus uvulæ. The lateral border is united with the lower margin of the perpendicular part, and is grooved by the lower end of the pterygopalatine canal. The medial border, the thickest, is serrated for articulation with its fellow of the opposite side; its superior edge is raised into a ridge, which, united with the ridge of the opposite bone, forms the nasal crest for articulation with the posterior part of the lower edge of the vomer.
The Vertical Part (pars perpendicularis; perpendicular plate) (Figs. 168,169).The vertical part is thin, of an oblong form, and presents two surfaces and four borders.
Surfaces.The nasal surface exhibits at its lower part a broad, shallow depression, which forms part of the inferior meatus of the nose. Immediately above this is a well-marked horizontal ridge, the conchal crest, for articulation with the inferior nasal concha; still higher is a second broad, shallow depression, which forms part of the middle meatus, and is limited above by a horizontal crest less prominent than the inferior, the ethmoidal crest, for articulation with the middle nasal concha. Above the ethmoidal crest is a narrow, horizontal groove, which forms part of the superior meatus.