Talk:Paper - Stapes, fissula ante fenestram and associated structures in man 2

From Embryology

3. Bast, T. H.: Development of the Otic Capsule: II. The Origin, Development and Significance of the fissula Ante Fenestram and Its Relation to Otosclerotic Foci, Arch. Otolaryng. 18:1-20 (July) 1933.

4. Anson, B. 1., and Martin, 1.: fissula Ante Fenestram: Its Form and Contents in Early Life, Arch. Otolaryng. 21:30.3-323 (March) 1935.

5. Wilson, J. G.: fissula Ante Fenestram and the Adjacent Tissue in the Human Otic Capsule, Acta oto-laryng. 22:382-392, 1935.

6. Bast, T. H.: Development of the Otic Capsule: III. Fetal and Infantile Changes in the fissular Region and Their Probable Relationship to the Formation of Otosclerotic Foci, Arch. Otolaryng. 23:509-525 (May) 1936.

Bast TH. Development of otic capsule III. Fetal and infantile changes in fissular region and their probable relationship to formation of otosclerotic foci. (1936) Arch. Otolaryng. 23: 509-525.

7. Bast, T. H.: Development of the Otic Capsule: IV. Fossula Post Fenestram, Arch. Otolaryng. 27:402-412 (April) 1938.

Bast TH. Development of otic capsule IV. Fossula Post Fenestram. (1938) Arch. Otolaryng. 27: 402-412.

8. Martin, J., and Anson, B. J.: Otic Capsule and Membranous Labyrinth of the Twenty-Nine Mm. (Crown-Rump) Human Embryo, Arch. Otolaryng. 27: 279-303 (March) 1938.

9. All reconstructions were prepared by the wax plate method from tracings made with an Edinger projection apparatus at a magnification of 125- diameters. The drawings of the reconstructions (figs. 1 to 12) were prepared at one-half the size of the reconstructions; those of the sections (figs. 31 to 59) at a magnification of 50 diameters, with the aid of an Edinger projection apparatus. sThe photographs of the reconstructions (figs. 13 to 17, 22 to 30 and 60 to 64) were taken at approximately one-fifth the size of the reconstructions; those of the cartilage and bone of the base (figs. 18 to 21) at approximately one-fourth the original dimensions. The reconstructions include sections as follows: 17 weeks (fig. 60), and 63), 155 sections; 3 years (figs. 3, 4, 22 and 23), 77 sections; 18 years (figs. 9, 10, 24 and 25), 116 sections; 57 years (figs. ll, 12 and 26 to 28), 121 sections, and 70 years (figs. 5, 6, 29, 30 and 64), I00 sections. Most of the sections are 20 to 25 microns in thickness. In magnifying the anatomic features in the reconstructions to the extent of 125 diameters all important details are brought to gross dimensions; e. g., the whole reconstruction may be 3 feet (90 cm.) in length. The reconstructions from the fetus (figs. 13 to 15), the infant (figs. 16 and 17), the child (figs. 22 and 23) and the 2 older adults (figs. 26 to 30) were made in segments in order that, by removing one portion, the form of the stapes and the course and relations of the fissula could be more effectively demonstrated; in the case of the child, the reconstruction was fabricated in three segments. (The upper piece is removed in figure 22 and the lower in figure 23.) The gray color indicates cartilage, while black marks a “cut surface” as represented by a transverse section in the series. Areas in the reconstructions marked out by white lines (figs. 24, fen. cartz'l., and fig. 29, 12.0. fiss.) are composed of cartilage in the section. Only cartilage and bone are separately indicated and not intrachondrial bone (cartilage islands). In figures 18 to 21 these two elements are reconstructed separately. Except for those of the fissula (figs. 60 and 64) the reconstructions represent solid tissues, namely, bone and cartilage. The fissular models, on the contrary, represent space (of the tympanic cavity, the vestibule and the fissular channel) ; they are essentially “casts” of the spaces enlarged to gross dimensions; they are employed as the only device by which the intraosseous space of the fissula could be adequately shown.

In the sections (figs. 31 to 59) haversian bone and hyaline cartilage are shown (not the modified cartilage, or intrachondrial bone) ; merely free margins of mucous membrane and perichondrium are shown, in order to render the figures somewhat diagrammatic. In the specimens from which figures 34 and 36 were prepared the mucous membrane is edematous and the layer therefore thickened. In otitis media, it may be recorded, edema of the submucosal tissue is sufficient to obliterate the space around the stapes. That this was actually the case was shown by preparing a reconstruction (not illustrated) of the mucous membrane.

In obtaining the measurements presented in the table, the length of the stapedial crus was taken as the distance (in a straight line) between the point of continuity of the crus with the tympanic surface of the base and the line of fusion of the crura to form the neck. In describing the head and neck it is difficult to find dependable limits for these subdivisions of the stapes; the authors have chosen to regard the head as substantially equivalent to the area of articulation, including not only the cartilaginous cap but the osseous lamina internal to the latter; the neck, then, is the portion of the ossicle intervening between the head and the conjoined crura. Since the crura usually meet earlier on the inferior than on the superior surface, the length of the neck will differ slightly on the two aspects. These morphologic features will be more fully discussed in a paper now in preparation (Beaton and Anson 13).

Table 3

Age Length of Stapes mm Length of Base mm Length of Anterior Crus mm Length of Posterior Crus mm Width of Base (anterior) mm Width of Base (posterior) mm
Fetus at term 3.048 2.488 2.304 2.523 0.840 0.936
3 months 3.424 2.712 2.952 2.536 1.008 1.264
3 years 3.216 2.600 2.840 2.688 0.784 0.960
18 years 3.144 2.544 2.416 2.136 1.024 1.130
57 years 2.272 2.592 2.456 2.256 1.264 1.024
70 years 2.696 2.536 2.496 2.328 1.376 1.168