Growth pattern of the middle ear in the gray short-tailed opossum, Monodelphis domestica

We studied the mass growth trajectories of middle ear ossicles and tympanic membrane oval window area in 19 specimens postnatal ages 30–180 days gray short-tailed opossum Monodelphis domestica . weighed skull three with appropriate balances. Using a binocular microscope provided grid, we measured length malleus incus, as well longest axis one perpendicular to it on both stapes footplate. The size variation was least squares regression analyses between various measurements. incus change little after 40 life, while does, reaching maximum at around 100 PND (postnatal days). This modularity trajectory is contrast shared evolutionary origin from branchial arch 1. maturation – indicated by previous work, that inner coupled improvement hearing sensitivity low high frequencies initial onset 29 PND.