. The anatomy of the human body. Human anatomy; Anatomy. 56 OSTEOLOGY. Connexions.—The two bones are articulated together : they unite also with the frontal, the ethmoid, and the superior maxilla, and likewise with the lateral cartilages of the nose : they afford passage to the vessels which establish a communication between the skin of the nose, and the mucous membrane of the nasal fossae. hiternal Structure.—The nasal bones are thick and cellular in their upper parts, thin and entirely compact in their lower, and are traversed by nervous and vascular grooves. Development.—The nasal bone is d
. The anatomy of the human body. Human anatomy; Anatomy. 56 OSTEOLOGY. Connexions.—The two bones are articulated together : they unite also with the frontal, the ethmoid, and the superior maxilla, and likewise with the lateral cartilages of the nose : they afford passage to the vessels which establish a communication between the skin of the nose, and the mucous membrane of the nasal fossae. hiternal Structure.—The nasal bones are thick and cellular in their upper parts, thin and entirely compact in their lower, and are traversed by nervous and vascular grooves. Development.—The nasal bone is developed from one single osseous point, which ap- pears before the end of the second month. Ossa Unguis, or Lachrymal Bones {Jigs. 31, 32). These are the smallest bones of the face: they are thin, like paper, and have the trans- Fig. 31. Fig. 32. parence, tenuity, and even the shape of a nail, from which circvim- stance one of their names has been derived. They are situated at the internal and anterior part of the orbit: their figure is irregularly quadrilateral: they are two in number, and, therefore, asymmetri- cal. They have two surfaces and four edges. The external or orbital surface {fig. 32) is divided into two unequal parts by a vertical ridge {a b), which terminates below in a sort of hook. The portion anterior to the ridge is narrow, and marked by a porous groove (c), which, when joined to the channel on the ascending process of the superior maxilla, forms the lachrymal groove (hence the name of lachrymal bone).* The portion (d) of the os unguis, which is posterior to the ridge, completes the inner wall of the orbit. The internal or ethmoidal surface {fig. 31) presents a furrow {a' b), which corresponds to the external ridge; the portion (c') in front of the furrow forms part of the middle meatus ; behind is a rough surface {d'), which covers the anterior cells of the ethmoid. Of the four borders, the superior{a a') is rough, and articulates with the internal ang
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