My three year old got up from kneeling the other day and started to wiggle and jiggle a little, when I asked him if he was OK he said…
…”Mummy, I’ve got sparkly toes!”
“Mummy I’ve got sparkly toes”
That has to be the cutest description of pins and needles I have ever heard. He looked at me a little confused and wanted to know why his toes were sparkling… I gave him a simple explanation but even as I was talking… I could feel a blog coming on!
So what are pins and needles and why do we get them?
Parasthesia is the medical term for pins and needles. The pins and needles that most of us experience, just as my son did, are a result of pressure on a nerve, restricting its blood supply. This pressure is usually a temporary pressure caused by us leaning on a limb or part of the body in an awkward way.
This pressure on the nerve restricts its supply of blood and therefore prevents it from “charging up” and “firing off” in the usual manner. The signalling pathway gets interrupted resulting in the nerve firing off incorrectly or at a modified rate… and we feel this as a fuzzy, tingling, spiking sensation. If the nerve is suppressed for too long its signalling function stops all together and the area becomes numb. These sensations can usually be quickly and easily reversed by simply changing position and moving the area that is affected, thereby returning blood supply to the nerves.
A closer look
So now we have a general understanding we need to know how nerves operate to explain the phenomenon a little further. Nerves carry messages around the body; these messages can be transferred from one part of the body to another or from a part of the body to the brain, or vica versa. Nerves are made up of bundles of cells called neurons.
Unlike most cells in the body, neurons do not regenerate, this makes them among the oldest cells of the body
The longest cells in the body are neurons
Neurons are very specialised cells: they transmit electrical signals (nerve impulses)
Nerve impulses travel at a speed of approximately 25 metres per second
Neurons have a very high metabolic rate
When the sensation is a little more serious
It is this high metabolic rate that causes the nerves to start to shut down their process. If the blood supply to the nerve is cut off or reduced (as is the case when we are sitting on a limb) they cannot produce enough energy to keep recharging themselves so the smallest neurons start to operate more erratically. These small neurons are the ones that transmit signals of pain, hence the first sensation of pins and needles.
Certain medical conditions are associated with prolonged or chronic pins and needles. The sensation may be due to a trapped nerve or nerve damage or infection. It may also be due to exposure to certain toxins or medical drug treatments or alcohol. Chronic parasthsia can be a side effect of diabetes, hyperventilation, vitamin B 12 deficiency or malnutrition.
The sensation of pins and needles usually goes very quickly once the blood supply is re introduced to the area affected, however if the symptoms persist or reoccur it is best to seek medical advice.
Hope you enjoyed the blog, if you have a question, a comment or an idea for a topic you would like me to cover in a future blog please leave a comment!
nao
Science blogger and writer; Owner of Dr. How's Science Wows; Mother of three junior scientists who have taught me that to be a great scientist you need to look at life through the eyes of a child!
