Final answer:
During an otoscopic examination on an infant, the pinna should be pulled downward and back to allow for a clear view of the ear's inner structures. The ear is divided into three main sections and the middle ear contains the ossicles that transmit sound to the inner ear.
Step-by-step explanation:
During an otoscopic examination on an infant, the pinna is pulled downward and back. This maneuver is performed to straighten the ear canal, allowing for better visualization of the eustachian tube, middle ear, and inner ear structures, such as the cochlea. The otoscope provides a view into the ear to check for signs of infection, blockage, or other abnormalities. In the inner ear, when the oval window is forced inward, a pressure wave travels through the perilymph, stimulating nerves at the base of cilia in the organ of Corti, which is the sensory organ responsible for hearing.
The human ear consists of three main sections: the outer ear, middle ear, which houses the three ossicles known as the malleus, incus, and stapes, and the inner ear. These structures are crucial for transmitting vibrations from the eardrum to the inner ear. Without the malleus and incus, the vibrations captured by the pinna would not reach the stapes and then be sent to the cochlea.