Skip to main content
Go to homepage

Print Page

What Are Reflexes?

Have you ever wondered why your leg kicks when the doctor taps your knee with that little rubber hammer? It's because of your reflex.

What's a Reflex?

A reflex is an involuntary (say: in-VAHL-un-ter-ee), or automatic, action that your body does in response to something — without you even having to think about it. You don't decide to kick your leg, it just kicks. There are many types of reflexes and every healthy person has them. In fact, we're born with most of them.

Protective Reflexes

Reflexes protect your body from things that can harm it. For example, if you put your hand on a hot stove, a reflex causes you to immediately remove your hand before a "Hey, this is hot!" message even gets to your brain.

Other protective reflexes are blinking when something flies toward your eyes or raising your arm if a ball is thrown your way. Even coughing and sneezing are reflexes. They clear the airways of irritating things.

What's a DTR?

The reflex that the doctor checks by tapping your knee is called the patellar, or knee-jerk, reflex. It is also known as a deep tendon reflex (DTR) because the doctor is actually tapping on a tendon called the patellar (say: puh-TEL-ur) tendon. This tap stretches the tendon and the muscle in the thigh that connects to it. A message then gets sent to the spinal cord that the muscle has been stretched.

The spinal cord very quickly sends a message back to the muscle telling it to contract. The contraction of the muscle causes your lower leg to kick out. You might wonder why such a reflex exists. This type of reflex is important in keeping your balance. When you're standing up, gravity might cause your knee to bend slightly, and this could make you fall if you didn't have the protective DTR to straighten that knee and keep you standing upright.

A doctor often checks for DTRs to make sure that the nervous system is working properly. Aside from the knee, they also can be checked along the outside of the elbows, in the crooks of the arms, and at the wrists and ankles.

So the next time your doctor taps you with that little rubber hammer, say, "Hey doc, how are my DTRs?"

Reviewed by: KidsHealth Medical Experts

Lea este articulo en Español

What next?

By using this site, you consent to our use of cookies. To learn more, read our privacy policy.

Summit Mall Play Area
Answer Key:
Click to expand
There are 10 nurses in the picture.

And we have many more pediatric primary care providers in Northeast Ohio. You can meet some of them here.
Summit Mall Play Area
Answer Key:
Click to expand
The five differences are:
– Phone color
– Coat pocket
– Stethoscope earpiece color
– Stethoscope bell dot
– Clipboard paper color

Need help finding a doctor, choosing a location or getting a general question about Akron Children's answered? Call us or fill out the form and we'll help in any way we can.
Summit Mall Play Area
Answer Key:
Click to expand
The two matching doctors are 9 and 14.

With virtual visits, you can see our pediatric experts from the comfort of home or wherever you are.
Summit Mall Play Area
Answer Key:
Click to expand
The correct path:
The Correct Path
We offer many ways to get pediatric care all over Northeast Ohio. Use this page to find the right kind of care and the most convenient location for you.