knee-jerk reflex,also called patellar reflex is a
sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which lies just below the kneecap. One of the several positions that a subject may take for the test is to sit with knees bent and with one leg crossed over the other so that the upper foot hangs clear of the floor. The sharp tap on the tendon slightly stretches the quadriceps, the complex of muscles at the front of the upper leg. In reaction these muscles contract, and the contraction tends to straighten the leg in a kicking motion. Exaggeration or absence of the reaction suggests that there may be damage to the central nervous system. The knee jerk can also be helpful in recognizing thyroid disease.
So, basically, it's a nerve reflex, you can't control it, it's just like when you put your hand on a hot kettle it pulls away, you can't help it.
When a doctor taps the knee with a small hammer he or she is testing a person's reflexes (sensory receptors, sensory neurons, spinal chord, interneurons, motor neurons, brain). If a person's leg instantly jerks upwards his/her reflexes are fine. His/her sensory receptors are affected by the stimulus (tap on the knee), which causes an action potential that travels along the sensory neurons and reaches the interneurons in the spinal chord, where it splits to either brain or motor neurons, and finally travels through motor neurons causing the muscle to flex (upward jerk).
A doctor taps the patellar ligament with a rubber reflex hammer. This is invoking the patellar, or knee jerk, reflex.
To see if your nerve cells are working correctly.
Without going into detail, the reason the knee "jumps" when the doctor hits it is because of a reflex.
reflexes
Reflex hammer.
The instrument used by a doctor to test knee reflex is a reflex hammer. The doctor will tap the patellar tendon just below the kneecap with the reflex hammer to elicit a reflex response, which helps assess the function of the nerves and spinal cord.
The proper name for the hammer a doctor uses to test your reflex is just "reflex hammer". It is a medical instrument used by physicians to test deep tendon reflexes and is an important part of a neurological physical examination.
The test that makes use of a special hammer is the reflex hammer test. It is used to check the reflexes in various parts of the body by tapping the tendon with the hammer to observe the muscle's response.
It has a few names but is basically known as a reflex hammer.
The test that makes use of a special hammer is the neurological examination test known as the reflex hammer test. This test is used to assess deep tendon reflexes by tapping on specific areas on the body with the hammer.
A person can purchase a reflex hammer by checking their local department store, second hand shops, Lowes, Walmart, or Sears. You may also ask your doctor where they would be available.
The knee reflex is also called the knee-jerk reflex by tapping the patellar tendon with a reflex hammer. This sends sensory information to the spinal cord at L4 and motor information back to the Quadriceps in the thigh (relaxing the hamstrings). This is reflex requires only two neurons. No interneuron. And so is very rapid. It is important in balance and posture.
someone tapping your knee and you kick
The modern reflex hammer is referred to as a Tomahawk or Taylor reflex hammer and was designed by John Taylor in 1888. That is the most well known one in the US. There is also the Babinski reflex hammer and it was developed in 1912 by Joseph Babinski and it is often seen in neurological settings.
Stethoscope Pen Torch Reflex Hammer Pen Tourniquet Spare venflons
It is a tomahawk-shaped rubber instrument used to test reflexes in order to determine if an individual's nerve reflexes are functioning properly. There is no specialized name for this instrument, though it is commonly referred to as a mallet.