. Anatomy, descriptive and applied. Anatomy. 98 SPECIAL ANA TO MY OF THE SKELETON. Fig. 66.—Ethmoid bone. Inner surface of right lateral of the corresponding side. There are two lateral masses, one on each side. The ethmoidal cells are not present at birth, but appear during the fifth year. In the disarticulated bone many of these cells appear to be broken; but when the bones are articulated they are closed in at every part, except where they open into the nasal fossae. The upper surface of each lateral mass presents a number of apparently half-broken cellular spaces; these are closed in, when
. Anatomy, descriptive and applied. Anatomy. 98 SPECIAL ANA TO MY OF THE SKELETON. Fig. 66.—Ethmoid bone. Inner surface of right lateral of the corresponding side. There are two lateral masses, one on each side. The ethmoidal cells are not present at birth, but appear during the fifth year. In the disarticulated bone many of these cells appear to be broken; but when the bones are articulated they are closed in at every part, except where they open into the nasal fossae. The upper surface of each lateral mass presents a number of apparently half-broken cellular spaces; these are closed in, when articulated, by the edges of the ethmoidal notch of the frontal bone. Crossing this surface are two grooves on each side, converted into canals by articulation with the frontal; they are the anterior and posterior ethmoidal canals (canalis ethmoidale anterius et posterius), and open on the inner wall of the orbit. The anterior transmits the nasal nerve and the anterior ethmoidal vessels; the posterior transmits the posterior ethmoidal A' The posterior surface also presents large irregular cellular cavities, which are closed in by articulation with the sphenoidal turbinated processes and the orbi- tal process of the palate. The cells at the anterior surface are completed by the lacrimal bone and nasal process of the maxilla, and those below also by the maxilla. The outer surface of each lateral mass consists chiefly of a thin, smooth, oblong plate of bone, called the OS planum (lamina papyracea); it forms part of the inner wall of the orbit, and articulates, above, with the orbital plate of the frontal; helow, with the maxilla; in front, with the lacrimal; and behind, with the sphenoid .and orbital process of the palate. In front of the os planum are found the anterior ethmoidal cells, which are completed by the lacrimal bone and the nasal process of the maxilla. From the inferior part of each lateral mass, immediately beneath the os planum, there projects downward an
Size: 1977px × 1264px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
