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| Figure 1 |
The voice box, a spectacular organ…well, depending on the circumstances
and your point of view. Known as the larynx in medical jargon, it’s the organ
vital for human communication, and a source of beautiful melodies and rhythms
able to tame even the most savage of beasts--think of the late Freddie Mercury of
Queen. On the other hand, it can have
the opposite effect--annoy, inflame, and lead to counter-actions from the
receivers of its hideous effects. Case
in point: one of my college dormmates sang nightly while showering (let’s call
him Earl) and so loud and terrible that a few others recorded his obnoxious
warbling, which was then aired by another dormmate (let’s call him Tony), a
D.J. at the college radio station. Earl
had his 15 minutes of fame, though the natural response from those listening to
the radio was to cover the ears. Such is
the life of the larynx. Needless to say,
Earl never made it to the big-time--he was no Freddie Mercury.
The larynx is located in your neck. OK, stupid first-start, but I’ll assume
nothing since some people believe it’s actually in the mouth or throat and not
related to the neck. So we’ll start with
fundamentals. First of all, take a feel
of the front part of your neck. You’’ll
notice a hard lump, known as the Adam’s Apple.
This is part of the larynx known as the thyroid cartilage. Thyroid
means shield, an in this case the
thyroid cartilage can be viewed as a folded shield forming most of the front
and sides of the larynx. The uppermost
part of the larynx is the hyoid bone, a horseshoe shaped structure that
attaches to the thyroid cartilage via the thyrohyoid membrane
(thyroid-to-hyoid; see the logic with medical terminology?) and also serves as
an attachment for some of the muscles of the tongue.
By the way, when we mention
throat, this is a general term meaning the area behind the tongue and above the
larynx. More specific medical lingo
names this the oropharynx, which includes nifty things as the palatine tonsils,
the uvula and soft palate, the back wall of the oropharynx and the tongue base
(back portion of the tongue). Check out
the post Sore Throat 101: Anatomy and Preliminary Stuff for a more thorough description of this anatomy.
The upper drawing of Figure
1 at the beginning of this article is a view from above. This is the type of view we obtain using a laryngeal
mirror to look down at the back of the throat, or with a fiberoptic scope
through the nose (see Nasopharyngoscopy),
or the view an anesthesiologist has when about to intubate a patient (place a
breathing tube).
Figure 2 is a sagittal section of the larynx. Imagine
slicing the neck and larynx vertical down the middle, not unlike filleting a
fish down along its spine. This figure
is then a side-view showing various structures as labeled.
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| Figure 2 |
The true vocal cords and the space between is also called
the glottis or glottic airspace. The structures of the larynx above the
glottis is known as the supraglottis,
and the structures below up to the first tracheal ring is called the subglottis.
The larynx serves two functions. Naturally it creates one’s voice. This is accomplished mainly when the true vocal
cords open and close, or in medical lingo, abduct and adduct. This allows air to pass through the glottic airspace between the vocal cords to generate sound. Other muscles within and outside of the
larynx are also involved with this process.
The larynx serves two functions. Naturally it creates one’s voice. This is accomplished by movement of the true vocal cords. The true vocal cords move outward and away from one another (abduct in medical lingo) to open the glottic airspace, or move inward towards one another (adduct) to close the glottic space. Air travels through a partially closed glottic space between the vocal cords to generate sound. Other muscles within and outside of the larynx are also involved with this process.
The larynx serves two functions. Naturally it creates one’s voice. This is accomplished by movement of the true vocal cords. The true vocal cords move outward and away from one another (abduct in medical lingo) to open the glottic airspace, or move inward towards one another (adduct) to close the glottic space. Air travels through a partially closed glottic space between the vocal cords to generate sound. Other muscles within and outside of the larynx are also involved with this process.
The second function is to protect the airway. The epiglottis
is a flap of tissue at the top of the larynx which closes the larynx while
swallowing. More importantly, the true
vocal cords adduct (move inward) to close the glottic space, preventing spillage
down into the trachea and lungs. The
false vocal cords also do the same.
The production of the voice and unique vocal qualities arise
not simply from adduction and abduction of the true vocal cords. In fact, if you visualized the vocal cords of
different singers, orators or anyone else for that matter, you couldn’t
distinguish one from the other based purely on anatomy since they’d virtually
look alike. Voice production involves a
complex array of vocal cord movement, use of the neck, chest, oral and
oropharyngeal muscles, nasal resonance, proper breathing techniques, to mention
just a few components. It’s all in the
way sound waves are shaped as air travels from the lungs, to the trachea, through
the larynx and through all the other structures of the throat (oropharynx), mouth
and nose and ultimately to the ear of the receiver; merely viewing the larynx
in action would give no clue as to the identity of the speaker, whether it be
Freddie Mercury or Earl The-Shower-Crooner.
Sorry Earl.
©Randall S. Fong, M.D.
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