. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Lagena. f â outturns/ - Malleus â Pharynx" Laaena' Eustachian Tube ^V^^/vMalleu Cochlea Fig. 691. Diagrams of stages in the development of the ear. (After Brandt.) Across the inner end of the auditory canal and separating it from the middle ear is the "ear drum," or external tympanic membrane, which is attached in a groove, the tympanic sulcus. In man it is about 1 mm thick and 10 mm in diameter, being slightly thicker in the center than aro
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Lagena. f â outturns/ - Malleus â Pharynx" Laaena' Eustachian Tube ^V^^/vMalleu Cochlea Fig. 691. Diagrams of stages in the development of the ear. (After Brandt.) Across the inner end of the auditory canal and separating it from the middle ear is the "ear drum," or external tympanic membrane, which is attached in a groove, the tympanic sulcus. In man it is about 1 mm thick and 10 mm in diameter, being slightly thicker in the center than around the margin. It is set obliquely across the passage-way, and thus a larger ear drum with a greater expanse of surface is exposed to the impact of vibrations than would be possible if it extended squarely across at right angles to the auditory canal. The ear drum is relatively nearer the surface in a child than in an adult, while a newly born infant is temporarily deaf until the collapsed tympanic cavities are filled with air by way of the Eustachian tubes, follow- ing the effort that accompanies the first protesting cries with which it greets the world. These "first cries" of the newly born have been called the most joyful sounds in all nature, for they assure the anxious listeners that the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
