Knuckle Cracking !

Ever wonder where the ‘snap, crackle and pop’ sound comes from when you crack your knuckles?

The answer may surprise you.

What actually does the ‘popping’ is not the bones or the joints themselves, but the little capsules of liquid that lie in between the bones.  It’s called “synovial fluid”. 

When we pull or bend our fingers beyond their natural limits, the bones and joints pull apart.  The ‘synovial capsule’ is then stretched.  Because of its expansion, the pressure in the synovial fluid decreases. With that bubbles quickly form, expand and then burst. 

The “burst of the bubble” is what we are hearing during a knuckle crack.

The ultimate question you are probably asking…

“Does cracking knuckles cause arthritis like my mom once told me?”

 Well, your mother was probably making assumptions…either that or she was a bit grossed-out by the whole thing and just wanted it to stop.

After many tests, there is no clear evidence that cracking knuckles causes arthritis.   There is however some evidence suggesting that grip-strength may slightly decrease for habitual knuckle-crackers. 

What the popping does seem to do is increase mobility in joints. 

It is of course possible to crack many other joints other than our knuckles – Eg. back, neck, hips, wrists, shoulders, toes, ankles, etc.

I suppose this is why we have chiropractors – The true masters of “synovial bubble popping”.

Appendix...Useless?

Eyes are made for seeing and feet are made for walking…

But did you know that certain parts of our bodies are virtually useless? Some of these apparently‘lost their function’ over time. 

So, while our ancestors may have had a use for them many moons ago, in today’s world they really don’t add much value.  Similar to the way cassette tape players in cars are losing their function as we’ve evolved to CDs and MP3 files. Today, few (if any) cars are built with a tape-deck – our bodies seem to change with the times as well.

An example in Humans…

The Appendix

The appendix does about as much for a human as wings do for an ostrich (Hint: Ostriches don’t fly…).

Evolutionary theorists believe that our appendix may have been important to our early ancestors who were big time plant-eaters. 

Today the appendix is a small pouch that doesn’t directly assist us with digestion.  So, perhaps the appendix lost its power as a result of our increased consumption of meat. 

With a bit of humour, Paleontologist Alfred Sherwood Romer once remarked that the major purpose of the appendix was probably to give financial support to the surgical profession.  (The Vertebrate Body, 1949). 

Each year, there are hundreds of deaths from appendicitis and hundreds of thousands of appendectomies performed.

The vast majority of people who have their appendix removed, don’t miss it at all – perhaps the greatest bit of proof that it is of no real importance.

Tonsils & Adenoids...Useless parts ?

Tonsils & Adenoids – seems they are about as useful as ashtrays on a motorbikes.

It is sometimes argued that tonsils and adenoids could be considered part of our immune system – protecting us from viruses and infections – particularly in children.

However their design is not effective in dealing with the variety of viral infections that people encounter in today’s society.

Tonsils and adenoids are apparently the product of an immune system that was developed in a time when children didn’t have exposure to many other people andtheir germs – These days, all the toxins in our environment and food, the large population and the variety of germs being passed around at daycares, schools etc. is far greater than it would have been back then.

The bottom line is – we can very easily live without them…especially as adults.

In fact many people do.

Tonsils and adenoids sometimes cause more harm than good.  They get infected quite often in children, causing frequent illness.

In these cases, they are surgically removed with no ill-effects.

Wisdom Teeth ...Useless Body part ?

Wisdom teeth – they’re about as useful as a fifth wheel on a car!

These teeth grow way in the back of our mouths.  As you know, dentists often remove wisdom teeth, sometimes before there are even any problems with them. 

Wisdom teeth often grow-in crooked or are ‘impacted’ and can eventually cause pain.  Theearlier in life they are removed the easier they are removed – as the roots haven’t developed much.

Our early ancestors may have needed these teeth more than us.  Having more teeth would not only help in the chewing of tough animal flesh, but some people believe it also aided in the chewing of plants – something that helped compensate for an inability to easily digest cellulose (found in plants).  Over time, as our diets changed, our jaws became smaller…but wisdom teeth still tend to appear.

Some scientists in Japan have actually harvested stem cells from extracted wisdom teeth.  In some cases patients getting their wisdom teeth pulled have an option to have the stem cells gathered and saved in case they might ever be needed in the future.

So, not only don’t we need our wisdom teeth, they may actually be more useful out of our mouths than in.

Untold Powers of the eyes....

It’s old news that our eyes make us see…But have you considered how our eyes speak? 

As the saying goes, “The eyes are the windows to the soul”.  

Eye contact is a crucial part of our non-verbal communication.

Our eyes can tell others we’re listening, interested or not paying attention. 

They can also communicate a whole range of emotions – happiness, anger, boredom, surprise, etc.

In North America – eye contact is often associated with trust. 

People who avoid eye contact can sometimes come across as deceitful. On the other hand, it can also indicate shyness or intimidation.   

Looked at differently, someone who nevertakes their eyes off of you may come across as a bit ‘creepy’ or aggressive.

So if you’re intentionally trying to communicate your trustworthiness, be sure you glance away now and then…or at the very least, blink.

Cultural Differences…

In some East Asian, African and Native North American cultures it is considered disrespectful to look a more senior or dominant person in the eye.

And as a sign of respect, some Middle Eastern cultures also feel there should be limits to the amount of eye contact made between members of the opposite sex (with the exception of spouses and family). 

Animal Alert!!

If ever caught face to face with a bear, giving it the ‘evil eye’ may not help you…

Many mammals including bears, dogs and chimpanzees, instinctively interpret direct eye contact as a threat. 

Spinning Dancer and the Optical Illusion.....

It is estimated that about 75% of the information we receive from our surroundings comes through our sense of sight.

But can we always trust what we are seeing?

If you’ve been on the internet enough, you’ve probably come across the image of the “spinning ballerina”. 

It asks the question:  Is she turning clockwise or counter-clockwise?

Depending on what direction you see her turning, they suggest it can be determined if you are “right or left-brained”.

What do the experts say?

Well, many experts think this is hog-wash and unlikely to be true! But leaving “brain-sidedness” to the side…

The spinning dancer is a great example of anoptical illusion. Stare at her long enough and you’re likely to see her spin both ways.

Optical illusions fool our brains into ‘seeing’ things that are not actually a good representation of reality.

One of the main reasons optical illusions work is because many of the eyes’ receptors perceive images and colours at different rates of speed.

So, depending on how an image is put together using colour, brightness, depth, movement etc. the receptors might be sending false images to the brain.

A Practical Use For Optical Illusions…

Interior decorators are sometimes known for creating optical illusions.

With the right colour combinations or contrast in a tiny downtown apartment, we can create the ‘perception’ of space. 

Sometimes getting tricked is a good thing.

Mystery Eye Twitching...

Has your eye ever twitched uncontrollably? 

This can last a day or two or sometimes as many as 2 or 3 weeks.

What’s actually twitching is the bottom eyelid.  It is a type of muscle spasm.

Officially called blepharospasm, it is completely harmless…but really, quite annoying. 

Why does this happen, anyway?

The exact reason our eyes twitch is not known, but the experts do have a few ideas.

Check out this list:

Eyelid twitching tends to occur when…

• We are under stress
• We consume too much caffeine
• We don’t get enough sleep
• We stare at a computer screen too long