11 medical devices that changed the world

Medical devices may sound like a modern invention, but they in fact have helped us manage and treat diseases for centuries

Here are our top ten picks of medical gadgets that play a significant role in our lives, many of them so ubiquitous that we sometimes take them for granted.



We have to credit a modest 19th-century Parisian doctor for having invented the stethoscope.

In 1816, while examining a female patient with heart disease, Dr René Laennec faced a conundrum: He needed to hear what was ailing her but was reluctant to press his ear to the woman’s chest.

So, the clever doctor improvised, rolling up a notebook into a tight cylinder. He put one end on his patient’s chest and the other to his ear.

And he heard, lub-dub, lub-dub, lub-dub, the sound of the heart,” says medical historian Dr Jacalyn Duffin.

“It’s one of the top inventions in medical history.”

The stethoscope changed the way doctors and nurses would treat patients. For the first time, they were able to listen and hear all of the noises from within the body. Besides listening to the sounds of the heart, the stethoscope is also used in diagnosing diseases of the lungs and bowels.

Clinical Thermometer


The word thermometer originated from the Greek words thermos (“warm”) and meter (“to measure”). It is unclear who the original inventor of the device was, but one instance of an instrument to measure temperature was the thermoscope, invented by Galileo in the late 1500s and based on the principle that the density of a liquid changes in proportion to its temperature.

In 1714, Daniel Gabriel Fahrenheit invented the first mercury thermometer, which is still in use today.

The digital thermometer, a modern invention, is now preferred over the mercury thermometer, which is being phased out for medical use due to the toxicity of mercury.

Hypodermic Needle


Ancient Greeks and Romans used thin, hollow tools to introduce fluids into the body, a precursor to the modern needle. In 1656, Christopher Wren used a goose quill as a crude needle to deliver intravenous injections into dogs.

The hypodermic needle as we know it was invented in the mid-1800s by Charles Pravaz and Alexander Wood. Hypodermic refers to anything just below the surface of the skin.

Today, the hypodermic needle is used together with a syringe to inject or extract fluids, medication and blood from our bodies with minimal pain and reduced risk of contamination.



We use spectacles for two main reasons: vision correction and eye protection. In historic times, monks and scholars who were using an early prototype of eyeglasses had to hold the lenses in front of their eyes or balance them on their noses to keep them from falling off.

As printed books became easily available in the 1900s, the number of cases of myopia increased, which led to eyeglasses being produced in greater quantities.

Modern spectacles can be used to correct both distant and near vision (bifocal glasses) and shield against ultraviolet light (sunglasses), the latter of which has taken on a new twist as a fashion statement.

X-Ray Imaging


Wilhelm Conrad Röntgen won the first ever Nobel Prize in Physics in 1901 for his discovery of electromagnetic radiation in a wavelength range known today as X-rays.

After accidentally discovering radiation that could pass through various substances that are opaque to ordinary light, Röntgen tested his invention by photographing his wife’s hand, which clearly revealed her wedding ring and the bones in her fingers.

Since then, X-rays have had many important uses in medicine: doctors use X-rays to study our bones while dentists use X-rays to detect diseases of the teeth. X-rays are also used in radiotherapy to stop cancer cells from growing and multiplying.

Cardiac Pacemaker


The pacemaker, a small implantable device that regulates the human heartbeat, has saved millions of lives since it was invented in 1926 by two Australian doctors.

The early pacemaker prototype was portable and consisted of two poles: one was connected to a skin pad soaked in salt solution while the other consisted of a needle that was inserted into the patient’s cardiac chamber.

Sounds dreadful, but, believe it or not, its inventors managed to revive a stillborn baby using the primitive device. Along with improvements in battery life, today’s pacemaker batteries can run for up to 20 years and even be recharged through the skin.

Hearing Aid


The hearing aid, also known as a hearing instrument, is a device designed to amplify sound. In 1899, Miller Reese Hutchinson invented the first electronic hearing aid made of a carbon microphone, battery and ear set.

The Akouphone, as it was called, was so large that it had to be placed on a table! Just over a decade later, the Hutchinson Acoustic Company created the first wearable hearing aid called the Acousticon. The device was smaller and portable, although early models were still cumbersome to carry around.

Newer hearing aids are now so small that they can be effectively concealed while in use, and some even contain features that reduce background noise.

Led Phototherapy


Affecting 60 percent of new-born’s, hyperbilirubinemia, more commonly known as jaundice, is caused by the build-up of bilirubin, a liver by-product that is often found in high levels in new-born’s.

If left untreated, bilirubin can spread into the brain, where it causes long-term damage.

The solution is surprisingly simple: Phototherapy, which involves shining blue LED light on a baby for approximately three days, converts bilirubin into a water-soluble form that can be excreted from the body.

Prosthetics and Implants


The invention of prosthetic (artificial) limbs has given amputees, who would otherwise be dependent on crutches or wheelchairs, a chance to regain their mobility. Likewise, knee and hip implants have helped the elderly and people with osteoarthritis achieve mobility again.

These days, carbon fibre is used instead of metal to make stronger, lighter and more realistic artificial limbs.

Futuristic prosthetic limbs even have inbuilt myoelectric sensors that process brain signals to automatically carry out tasks such as gripping and walking.

Drug-Eluting Stent


A stent is a metal scaffold inserted into a narrowed peripheral or coronary artery to improve blood flow to the heart. Interventional cardiologists deliver the stent into an artery using a balloon angioplasty procedure, which expands and locks the stent in place.

Drug-eluting stents can be coated with drugs that are slowly released into the arterial wall to prevent scar tissue formation during the healing process.

Although some controversy remains, they were approved by the US Food & Drug Administration after clinical trials showed that they were more effective than bare-metal stents in preventing repeat interventions, heart attacks and death.

Blood Glucose Monitor


To keep their blood sugar levels as close to normal as possible, diabetics need to monitor the level of glucose in their blood at least once a day.

Current technology to measure glucose in the blood includes the use of a portable testing meter called the blood glucose monitor. Using the device, a finger prick blood sample applied onto a chemical test-strip generates a simple numerical read-out within seconds.

More sophisticated blood glucose monitors in development include a non-invasive glucose breathalyser device and an implantable real-time glucose sensor that also releases insulin in a responsive manner.

Source: Asian Scientist