part of part of contributes to morphology of middle ear tympanic ring ectotympanic ring os tympanicum AAO:0000615 MA:0001225 tympanic annulus Gene notes: Gsc and Prx1 are essential for tympanic ring development A C-shaped membranous bone that provides physical support to the tympanic membrane. The tympanic ring develops sequentially from an initial primordium in the first branchial arch growing in a circumferential fashion around the first pharyngeal cleft into the second branchial arch (Mallo and Gridley, 1996). In most mammals, the tympanic ring exists only during embryonic life, when it coordinates proper development and positioning of the eardrum (see below), and then becomes integrated into the temporal bone[PMID]. tympanic membrane annulus tympanic anulus UBERON:0002218 EMAPA:19197 SCTID:95952001 intramembranous bone head bone