That little thing, where you whack just below the kneecap with a little hammer and their leg jumps…what’s the deal with that? Does the test have any medical value?
If your knee doesn’t jump, there’s probably something wrong with your nerves, so it cues the doctor to check into things.
Cecil did a column on this. Reflexes are an important part of the neurological exam. Hyperactive reflexes suggest upper motor neuron disorders (stroke, trauma, brain tumour or abcess, multiple sclerosis, etc.); weak reflexes lower motor neuron disorders (myopathies, spinal cord compression, etc.)
Here is Cecil’s column on reflexes.
I’ve got fairly sluggish reflexes, but my doctor (and neurologist and neurosurgeon) told me that’s okay as long as they’re the same bilaterally; that is, on both sides.
The knees aren’t the only place a doctor will tap. I’ve had my elbows, achilles’ tendons and wrists tapped. (I’ve got extensive spinal problems; my doc wants to make sure nothing’s getting pinched or compressed.)
Robin
Finally! The opportunity (no matter how forced) to share a rather useless factoid that has been wasting valuable space in my brain for over a decade:
The little hammer is called a plexor.
Thank you.