File:Anson1948 fig12.jpg

Fig. 12. Drawings of a reconstruction of the stapes in the 180 mm Fetus

Drawings of a reconstruction of the stapes in the 180 mm. (21 week) fetus (Wisconsin series 45 B); X 7: (a) the entire stapes, in superolateral view; (1)) segment 1 (see inset), viewed from below (that is, here inverted) ; (c) segments 2, 3 and 4 in superomedial view; (d) segment 3, from below (reconstruction inverted), with segment 4 removed; inset, reconstruction with segments lettered and with arrows recording the direction of View in the correspondingly lettered figures.

The drawings show the extent to which periosteal bone has been removed on the obturator surface of the base (a and b), crura and neck (c and d) and the degree to which the stapes throughout has been hollowed (I) to d). Cartilage now remains only on the articular surface of the head and on the vestibular surface and fenestral margin of the base of the ossicle (b and c). The addition of endochondral bone has converted the base into a thinned bilaminar plate ((2 and c). Such bone appears in limited amount as spicules in the area where the crura join the neck of the stapes (d).

Reference

Anson BJ. and Cauldwell EW. Stapes, fissula ante fenestram and associated structures in man: V . From the fetus of 160 mm to term. (1948) 48(3): 263-300.

Cite this page: Hill, M.A. (2024, April 25) Embryology Anson1948 fig12.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Anson1948_fig12.jpg

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G