Inferior Nasal Concha
The inferior nasal conchae are curved laminae which lie horizontally in the lateral walls of the nasal cavity (fig. 370). Each bone has two surfaces, two borders, and two ends.
The medial surface (fig. 372) is convex, perforated by numerous apertures, and traversed by longitudinal grooves for the lodgment of vessels. The lateral surface is concave (fig. 373), and forms part of the inferior meatus of the nasal cavity. The superior border is thin and irregular, and may be divided into three portions : of these, the anterior articulates with the conchal crest of the maxilla, and the posterior with the conchal crest of the palatine bone. The middle portion presents three processes, which vary in size and form. Of these, the lacrimal process is small and pointed and is situated at the junction of the anterior one-fourth with the posterior three-fourths of the bone: it articulates, by its apex, with a descending process from the lacrimal bone (fig. 371) and, by its margins, with the edges of the nasolacrimal groove on the medial surface of the body of the maxilla, and thus assists in forming the canal for the nasolacrimal duct. Behind this process a thin plate, named the ethmoidal process, ascends to join the uncinate process of the ethmoid (fig. 371). From the middle part of the superior border a thin lamella, termed the maxillary process, curves downwards and laterally; it articulates with the maxilla and the maxillary process of the palatine bone, and forms a part of the medial wall of the maxillary sinus (Fig. 386). The inferior border is free, thick, and spongy in structure, more especially in the middle of the bone. Both ends are more or less pointed, the posterior being the more tapered.
Figure 371
Ossification.-The inferior nasal concha is ossified from one centre; this appears about the fifth month of fetal life in the incurved lower border of the lateral wall of the cartilaginous nasal capsule. It is detached from the remainder of the nasal capsule during ossification.
Figures 372 - 373
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Vertebral Column