middle ear morphology trait round window morphology trait morphology trait of the fenestra of the cochlea fenestra rotunda morphology trait Any measurable or observable characteristic related to the shape, structure, color or pattern of the opening on the medial wall of the middle ear leading into the cochlea, closed in life by the secondary tympanic membrane; serves to regulate fluid pressure in the inner ear. cochlear window morphology trait VT:0004480 Trait.ontology fenestra cochleae morphology trait