Hanging from the back edge of your soft palate, the palatine uvula seems to serve several
functions, none of which are particularly necessary for most people, which is why it
can generally be removed with few, if any, noticeable side effects.
In fact, in the West, the “uvula” (name deriving from the Latin “uvola,” meaning
“small bunch of grapes”) is often cut out as part
of uvulopalatopharyngoplasty to help patients who suffer from sleep apnea.
Other cultures have long removed the uvula, sometimes as part of a ritual, to treat all
manner of “throat conditions,” as well as cure everything from vomiting and diarrhea
to rejecting breast feeding, growth retardation and even anorexia.
Today the surgery is still occasionally practiced among various ethnic groups in Eritrea, Ethiopia,
Kenya, Niger, Nigeria, Sierra Leone and Zarma.
So if you probably wouldn’t notice anything particularly different when it’s removed,
what does the uvula actually do and why do we still have one?
Beyond that it is necessary for producing important sounds, sometimes called uvular
consonants, in several languages, including French and Arabic, perhaps the most noticeable
role of the uvula is helping to keep the throat moist.
You see, the uvula is packed with serous and seromucous glands.
When muscle fibers in the uvula (musculus uvulae) contract, it results in these glands
excreting significant amounts of a thin form of saliva that gets splattered and dripped
around the throat as we speak and swallow.
In fact, one of the potential side effects of having your uvula removed is occasional
problems with a dry throat.
With the help of its internal muscular fibers, the uvula also aids the soft palate in sealing
off the passageway between your throat and your nose (called the nasopharynx) when you
swallow and speak, helping to make sure bits of food or liquid don’t go up your nose
and that the air and vocal vibrations are directed out of your mouth and not your nasal
cavity.
The partial role the uvula has in this has led some to speculate that it assists with
keeping the tone of our voices in a pleasing range, as it could help control both resonance
and subdue the nasal tone of the voice.
However, the soft palate alone is usually perfectly capable of sealing the nasopharynx,
and thus, in most cases the uvula is not necessary to put an end to a nasally sounding voice.
In rare cases, some individuals do have a problem with this, a condition called velopharyngeal
insufficiency, which, beyond potential issues like nasal regurgitation (bits of food and
the like going up your nose when swallowing), results in the individual having difficulty
saying consonants like “b”.
Given these primary functions of the uvula, it has been proposed that the reason humans
have a uvula is because it aids somewhat in speech, making it an accessory speech organ.
This theory is loosely supported by the fact that, outside of humans, only a few animals,
and this is individual animals, not species, have been found to even have one:
In 1992, researchers searched the mouth cavities in a number of animals . . . [including] dogs
and horses and cows and apes and sheep . . . . Of all animals in the study, a small underdeveloped
uvula was found only in two baboons.
Another function of the uvula relates to its role in the gag reflex, as it is one of only
five parts of the body that will potentially trigger it (the others being the roof of the
mouth, the backs of the tongue and throat, and the tonsils).
Having something the dangles down over the throat opening that can trigger this is obviously
beneficial over just the tissue around said opening performing this function.
However, as with the other stuff the uvula does for you, it isn’t really necessary
in this case either and, for most people, its removal would not likely inconvenience
them in the slightest, or even necessarily be noticed at all other than potentially visually.
Despite the uvula playing a role in the gag reflex, and despite other drawbacks, uvula
piercing is a thing.
A fascinating vestigial trait in humans is the palmar grasp reflex that newborn infants
(and even pre-born fetuses) display: studies of this reflex have revealed that newborn
humans can support their own weight by hanging from their hands for at least 10 seconds.
This activity mimics that of newborn monkeys, who must be able to grasp and hang onto their
mothers for significantly longer periods of time.
Human infants start to lose this reflex at about three months.
Of course, most have seen ultrasound pictures of human embryos with tails (this happens
in the sixth week).
Within a few weeks of development, however, for most the tail’s vertebrae fuse together
to form the coccyx and the tail, itself, disappears long before birth (although occasionally a
baby is born with a bit of the structure, see: Are Some People Really Born with Tails?).
Interestingly, not everyone is born with wisdom teeth anymore, as the evolution of the human
diet has led to their obsolescence.
Likewise, a thin strip of muscle thought to be important for hanging, the palmaris longus,
is believed to be missing in about 10% of the population.
If you’ve ever known someone who can wiggle their ears, this is due to auricular muscles
around the outside of the human ear.
Although most of us never use them, it is said that “through repeated effort . . . humans
can recover some ability to wiggle their ears.”