Tuning Fork Macro

Posted by Yonatan (New York, United States) on 11 December 2009 in Miscellaneous.

I will apologize ahead of time for the upcoming nerdiness. I find this stuff interesting and I think some of you might too.


Pictured above is a macro of my tuning fork. I don't play a musical instrument, so you are probably wondering why I have a tuning fork, and why I think it's interesting enough to share with you all. Well, this piece of equipment is in my medical bag and is an excellent tool that allows physicians to assess mainly two things: hearing problems and vibratory sensation problems. Here I will focus just on hearing.

If you do not know what a tuning fork looks like, here is typical example.


If a patient comes into the office and complains of difficulty hearing out of his right ear, I will make sure to use this tool during my physical examination. There are two tests that we use to assess a patient's hearing, the Weber test and the Rinne test. I'll briefly explain what on earth they are and hopefully you'll agree that they are pretty cool.


Let's assume that a patient comes into my office and is suffering from a middle ear infection. First I will perform the Weber test: I hit one side of the top of the fork to make it vibrate and then I place the bottom end of the fork in the middle of the patient's forehead, equidistant between the patient's ears. A person without any problem would hear the vibratory sounds emitted from the fork equally in both ears. This is not the case in our patient who has a right-side middle ear infection. Our patient will hear the sound greatest in the affected (right) ear. Why is? Think of it this way, this patient has what we call unilateral conductive hearing loss. Sound waves are not being properly conducted through the right ear canal because it's all clogged up with infected fluid. When the tuning fork vibrates and emits its sound, the right ear still hears it because our bones also conduct sound. What the right ear doesn't hear is the outside ambient sound. The right ear perceives the tuning forks sound to be louder in the right ear than the left because the right ear doesn't hear ambient noise, but the left does. The result is perceived amplification of the sound in the right ear compared to the left.


If you are still with me, I'll now explain the second part of this ear exam, the Rinne test. This test is necessary to establish whether our patient is suffering from conductive hearing loss (from an ear infection) or sensorineural hearing loss (a nerve/brain related problem). To perform this test I make the tuning fork vibrate and then I place the end of the fork on a bone just behind the ear, the patient's mastoid process. I ask the patient to tell me when he no longer hears the fork vibrating. When the patient indicates so, I then move the fork to the ear and ask if he can hear the fork vibrating. This test is repeated on the other side/ear. In a normal person, air conduction is greater than bone conduction. Meaning that normally after you stop hearing the tuning fork that was placed on your mastoid process bone (your bones no longer transmit the forks vibrations), you can still hear it when it's placed by your ear canal opening. In our patient, bone conduction was greater than air conduction on the right side (abnormal) and on the left side air conduction was greater than bone conduction (normal).


What does this all tell us. These are the findings that are expected in somebody with a middle ear infection. In our patient, the Weber test lateralized to the affected right side and the Rinne test established that the right side was suffering conductive hearing loss, not sensorineural hearing loss.


Pretty cool stuff! If you actually read this, I applaud you.

If you enjoy my work you may visit my permanent website where you can view my photos.

www.yonatangreenstein.com


Thank you for taking some time to take a look at my photographs. I hope you enjoy your stop at my blog.


I invite you all to visit frequently and leave comments and feedback. I would really appreciate constructive criticism that will help me improve. You don't need to be a photographer to help me, tell me what you like and don't like. If you have any suggestions of interesting things to shoot or fun techniques to try I'd also love to know.


Best wishes,

Yonatan

Olympus E-510
1/4 second
F/8.0
ISO 400
50 mm

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