. Nursing in diseases of the eye, ear, nose, and throat . cle or lobe of the ear isdevoid of cartilage and consists chiefly of connectivetissue and fat. The cartilage of the external ear is pro-longed inward in the shape of a tube from the concha toform the outer two-fifths of the external auditory adults this external auditory canal is about 1] incheslong and is narrowest at its middle, which is also thehighest point of its floor, for as it runs inward it is directed 1 The author is indebted to Dr. P. B. Barringers useful Ab-stract of Physiology for a large part of this O
. Nursing in diseases of the eye, ear, nose, and throat . cle or lobe of the ear isdevoid of cartilage and consists chiefly of connectivetissue and fat. The cartilage of the external ear is pro-longed inward in the shape of a tube from the concha toform the outer two-fifths of the external auditory adults this external auditory canal is about 1] incheslong and is narrowest at its middle, which is also thehighest point of its floor, for as it runs inward it is directed 1 The author is indebted to Dr. P. B. Barringers useful Ab-stract of Physiology for a large part of this OUTLINE OF ANATOMY AND PHYSIOLOGY OF EAR 177 first upward and forward and then downward and for-ward to the drum membrane. Therefore, in order tostraighten the canal to examine or irrigate it the auricleshould be drawn upward and backward. In infants atbirth and for some months following, the upper andlower walls of the external canal are in contact, owing tolack of development of the bony canal. Consequently, Helix Darwins tubercle Concha HelixA nthelix. Fig. 35.—Right auricle: Nomenclature after Spalteholz (Barnhill and Wales). up to two years of age the canal is best straightened forexamination or irrigation by pulling the auricle down-ward and backward. As the development of the canaltakes place in older children it is straightened by pullingbackward and then backward and upward, as in its entrance or meatus the canal expands a little in its vertical diameter ((|)), and at its inner end it12 178 EYE, EAR, NOSE, AND THROAT NURSING expands horizontally (-S-), in view of which most earspecula are made with oval tubes. The inner end isclosed by the drum membrane, which extends obliquelyacross it, making the anterior wall and floor of the canallonger than the roof and posterior wall. The nerve-supply of the canal, from Arnolds branch of the pneumo-gastric nerve and from a branch of the fifth nerve, is
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