| Namespace | MPheno.ontology | Obsolete | false |
| description | any structural anomaly of any of the four membranes that separate the branchial pouches from the corresponding branchial grooves in a developing embryo; each membrane is initially composed of an inner layer formed by the endodermal lining of a branchial pouch and an outer layer formed by the ectodermal lining of the branchial groove; later, these two layers become separated by a thin layer of mesoderm; only the first branchial membrane contributes to the formation of an adult structure, i.e. the tympanic membrane (aka eardrum); the second, third, and fourth membranes are obliterated |
