Why do your knuckles pop? - Eleanor Nelsen

Translator: Cristina Blanco Reviewer: Servizo de Normalización Lingüística

Que é ese son?

What's that sound?

Depending on whom you ask,

Segundo a quen lle preguntes,

the crackle of popping joints is either the sound of sweet relief

o ruído ao estalar as xogas é ou ben o son dun doce alivio

or the noxious tones of a stomach-turning habit.

ou algo desagradable digno dun costume nauseabundo.

Really, though. What's that sound?

Pero, en serio, que é ese son?

Quero dicir, porque ao dobrar as xogas de certa maneira producen ese son?

I mean, why does bending your joints in a certain way make them pop like that?

Scientists have offered several explanations,

Os científicos ofrecen varias explicacións,

including rapidly stretching ligaments,

coma a elongación repentina dos ligamentos

and in severe cases, actual bones grinding against each other.

e, en casos extremos, o fretado dos ósos un contra o outro.

But the most common explanation

Pero a explicación máis común

for why your stretched-out joints sound like bubbles popping

do porqué ao estirar as xogas se xera un son de burbullas estaladas

is that, well, there are bubbles in there.

é… iso, que hai burbullas.

The joints in your fingers are the easiest ones to crack,

As xogas dos dedos son as que estalan con máis facilidade,

but many people also crack the joints between vertebrae in their neck and back,

pero moitos tamén fan estalar as xogas entre as vértebras do pescozo e do lombo

and even their hips, wrists, shoulders and so on.

e ata as cadeiras, pulsos, ombreiros e demais.

All these joints are synovial joints,

Todas estas xogas son articulacións sinoviais,

e son as máis flexibles do corpo.

and they're the most flexible ones in your body.

The space between the two bones is filled with a viscous liquid,

O espazo entre os ósos está cheo dun líquido viscoso,

synovial fluid, which contains long, lubricating molecules,

o líquido sinovial, que contén largas moléculas lubricantes,

like hyaluronic acid and lubricin.

coma o ácido hialurónico e a lubricina.

Synovial fluid is more or less the texture of egg yolk

O líquido sinovial ten máis ou menos a textura dunha xema de ovo

and its primary purpose is to cushion the bones

e o seu propósito principal é acolchar os ósos

and help them glide past each other.

e axudarlles a escorregar un sobre o outro.

It also contains phagocytic cells

Tamén contén células fagocíticas

that help clean up any bone or cartilage debris that ends up in the joint.

que axudan a limpar os ósos e cartilaxes dos residuos presentes na xoga.

But the reason it's important for knuckle cracking

Pero a razón de ser importante ao estalar os cotobelos

is that, like other fluids in your body,

é que, igual ca outros fluídos corporais,

it contains lots of dissolved gas molecules.

contén unha gran cantidade de moléculas gasosas disoltas.

Os amantes de estalar xogas saben que, para conseguir un bo estalo,

Knuckle-crackers know that to get that satisfying pop,

you stretch the joint farther than it normally goes

teñen que estirar a xoga máis do habitual

estirando os dedos cara a atrás, por exemplo.

by bending your fingers backwards, for example.

Ao facer iso, os ósos afástanse os uns dos outros.

When you do that, the bones move away from each other.

O espazo entre eles agrándase,

The space between bones gets bigger,

but the amount of synovial fluid stays constant.

pero a cantidade de líquido sinovial queda constante.

That creates a low-pressure zone

Iso crea una zona de baixa presión

que inflúe sobre os gases disoltos do líquido sinovial,

that pulls dissolved gases out of the synovial fluid,

just like the carbon dioxide that fizzes out of soda

igual que o dióxido de carbono que burbulla nun refresco

when you twist open the cap.

cando se abre o tapón.

Inside the joint, the escaping gases form a bubble with a pop.

Dentro da xoga, os gases que escapan crean unha burbulla sonora.

But the bubble doesn't last long.

Pero a burbulla non dura moito tempo.

The surrounding fluid presses on it until it finally collapses.

O fluído que a rodea apértaa ata que finalmente a fai estalar.

The bubble's gases scatter throughout the synovial cavity

As burbullas de gas esparéxense no espazo sinovial

and slowly dissolve back into the fluid over the course of about twenty minutes,

e vólvense disolver lentamente no líquido, un proceso que dura 20 minutos,

which is why it can take a while before you can pop the same joint again.

motivo polo cal ten que pasar un tempo para poder estalar as xogas de novo.

Algúns científicos pensan que, en realidade, hai dous estalidos:

Some scientists think there may actually be two pops.

One when the bubble forms, and another when it bursts.

un cando se forma a burbulla e outro cando estala.

Ao estalar unha xoga, o seu tamaño aumenta nese intre,

Popping a joint temporarily enlarges it,

which may be why dedicated knuckle-, neck- and back-crackers

e esa pode ser a razón pola que os amantes do estalido articular

say the habit makes their joints feel looser and more flexible.

din que este hábito fai que as xogas se sintan máis soltas e flexibles.

Pero terás oído dalgún familiar preocupado ou dun compañeiro molesto

But you may have heard from a concerned relative or annoyed officemate

that cracking your joints will give you arthritis.

que estalar as xogas produce artrite.

A doctor named Donald Unger heard this, too.

Un médico chamado Donald Unger tamén o oíu,

así que decidiu rebater as advertencias da súa nai

So, determined to disprove his mother's warnings,

he cracked the knuckles of his left hand repeatedly for 50 years,

estalando os cotobelos da man esquerda en repetidas ocasións durante 50 anos,

while the right-hand knuckles went unpopped.

sen repetir a acción na man dereita.

36,500 cracks later, both hands were arthritis-free.

36 500 estalidos despois, ningunha das mans presentaba signos de artrite.

For this selfless act of devotion to science,

Por este acto desinteresado de devoción á ciencia,

Dr. Unger received an Ig Nobel Prize,

o Dr. Unger recibiu un Premio Ig Nobel,

a parody of the Nobel Prize that recognizes wacky,

unha parodia do Premio Nobel que premia logros científicos extravagantes,

but weirdly fascinating, scientific accomplishments.

pero fascinantes.

Unger wrote that his results should prompt investigation into other parental beliefs,

Unger escribiu que os seus resultados deberían motivar

a investigación doutras crenzas paternais,

coma a importancia de comer espinacas.

like the importance of eating spinach.

O xurado aínda non se pronunciou.

The jury's still out on that one.

As for knuckle-cracking,

En canto a estalar os cotobelos,

one study suggests that all that joint stretching

un estudo indica que, ao estirar as xogas

and bubble bursting can cause your hands to swell

e estalar as burbullas, podes facer que se inchen as mans

and weaken your grip.

e debilitar a forza de agarre.

But the biggest proven danger seems to be annoying those around you.

Pero o maior risco probado ata o momento é que molesta os que te rodean.