Bridled (Long-Tailed) Weasel (Mustela frenata)
More medieval medicine:
- For deafness or headache: Take one weasel heart, coat in wax, and place in ear canal. Leave in place for at least one day. (The Subtleties of Diverse Creatures. Hildegard of Bingen, ca. 1160.)
Popular Science Monthly, Vol. 87. Edited by J. McKeen Cattell, 1915.
Image: Viviparous Quadrupeds of North America. John James Audubon, 1848.
Pathway of Sound
The auricle of the ear serves to “capture” sound waves, which travel down the auditory canal and hit the tympanic membrane (ear drum), causing it to vibrate and send vibrations through the small bones of the middle ear: the malleus, incus, and the stapes. The stapes connects to the oval window, which is the “window” (duh) between the middle and inner ear. The vibrations pass through the oval window and into the perilymph of the boney labyrinth of the inner ear, and eventually to the cochlea. The cochlea is filled with endolymph and houses the Organ of Corti. The vibrations carried through the perilymph causes the endolymph within the Organ of Corti to begin vibrating. The tectorial membrane is disturbed by these vibrations and “tickles” the microvilli of the hair cells between the basiliar and the tectorial membranes. The microvilli bend in response, triggering an actional potential and an impulse that is carried by the cochlear nerve to the temporal cortex where, alas, the impulse is interpreted as sound!
The inner ear and labyrinth, in situ and isolated. Innervation and vasculature displayed in situ.
Arterial and venous circulation of the tympanum (eardrum).
You can see how the inner ear sits within the temporal bone in these illustrations, and can get more of an idea how it fits into the skull. The vestibulocochlear nerve is shown clearly as the white chord-like structure entering from the bottom of the center illustration. This nerve carries signals to the brain regarding both hearing and balance.
Traité complet de l’anatomie de l’homme comprenant la medecine operatoire, par le docteur Marc Jean Bourgery. Illustrated by Nicolas Henri Jacob, 1831.
Partial Cross-Section of Adult Skull
Displaying the divisions of the ear and naso-pharyngeal cavity. As you can see, even though the skull has some pretty well-defined zones and areas, everything is a lot more inter-connected than most of us learn about in grade school. The close connection between the ear canal and throat is why, when you have a sore throat, many times earaches come along with it, and why when you have a sinus headache, the ears often feel “plugged up”.
A Practical Treatise on the Diseases of the Ear Including a Sketch of Aural Anatomy and Physiology. D. B. St. John Roosa, 1884.