Reference > Anatomy of the Human Body > Page 995
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Henry Gray (1825–1861).  Anatomy of the Human Body.  1918.
 
the lateral wall of this meatus is fully displayed. On it is a rounded elevation, the bulla ethmoidalis, and below and in front of this is a curved cleft, the hiatus semilunaris.
  The bulla ethmoidalis is caused by the bulging of the middle ethmoidal cells which open on or immediately above it, and the size of the bulla varies with that of its contained cells.


FIG. 856– Lateral wall of nasal cavity; the three nasal conchæ have been removed. (See enlarged image)

  The hiatus semilunaris is bounded inferiorly by the sharp concave margin of the uncinate process of the ethmoid bone, and leads into a curved channel, the infundibulum, bounded above by the bulla ethmoidalis and below by the lateral surface of the uncinate process of the ethmoid. The anterior ethmoidal cells open into the front part of the infundibulum, and this in slightly over 50 per cent. of subjects is directly continuous with the frontonasal duct or passage leading from the frontal air sinus; but when the anterior end of the uncinate process fuses with the front part of the bulla, this continuity is interrupted and the frontonasal duct then opens directly into the anterior end of the middle meatus.
  Below the bulla ethmoidalis, and partly hidden by the inferior end of the uncinate process, is the ostium maxillare, or opening from the maxillary sinus; in a frontal section this opening is seen to be placed near the roof of the sinus. An accessory opening from the sinus is frequently present below the posterior end of the middle nasal concha. The inferior meatus is below and lateral to the inferior nasal concha; the nasolacrimal duct opens into this meatus under cover of the anterior part of the inferior concha.

Medial Wall (Fig. 854).—The medial wall or septum is frequently more or less deflected from the median plane, thus lessening the size of one nasal cavity

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