part of part of contributes to morphology of middle ear tympanic ring ectotympanic ring check amphibians in FMA, the tympanic ring is an anatomical line. Howevever http://www.ncbi.nlm.nih.gov/pubmed/11237469 states: 'the tympanic ring, which serves as support for the tympanic membrane, directs invagination of the first pharingeal cleft ectoderm to form the external acoustic meatus (EAM), which provides the outer layer of the membrane'. os tympanicum AAO:0000615 MA:0001225 tympanic annulus 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 relationship loss: part_of plectral apparatus (AAO:0000443)[AAO] SCTID:95952001 Gene notes: Gsc and Prx1 are essential for tympanic ring development tympanic anulus UBERON:0002218 Funnel-like ring structure located lateral to the ventral ramus of the squamosal, beneath the skin; it provides support to the tympanic membrane.[AAO] EMAPA:19197 in AAO 'Funnel-like ring structure located lateral to the ventral ramus of the squamosal, beneath the skin; it provides support to the tympanic membrane'. intramembranous bone head bone