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Continue to remove the floor of the middle cranial fossae laterally in order to unroof the external ear canal. After the bone is removed, use forceps to remove the mucosal roof of the external ear canal. Identify the orientation of the external auditory canal in relation to the middle and inner ear.
With the external ear canal unroofed, observe the tympanic membrane (eardrum), with ossicles present and ossicles removed. The tympanic membrane separates the external ear canal from the middle ear cavity.Links and References:
Grant's: 7.150
Netter: 92