Knee-jerk reflex
Knee-jerk reflex (also known as the patellar reflex) is a type of reflex that is elicited by a sharp tap on the patellar tendon, which lies just below the knee. The reflex is caused by the stretch reflex mechanism to prevent the muscle from stretching too far.
Mechanism[edit | edit source]
The knee-jerk reflex is a monosynaptic reflex that involves a single synapse in the spinal cord. When the patellar tendon is tapped, the quadriceps muscle is stretched, which stimulates the muscle spindles. These sensory receptors send a signal to the spinal cord, which in turn sends a signal back to the quadriceps muscle, causing it to contract and the lower leg to kick forward.
Clinical significance[edit | edit source]
The knee-jerk reflex is used in neurological examinations to test the function of the nervous system. An absent or decreased knee-jerk reflex may indicate damage to the peripheral nerves, spinal cord, or muscle disease. An exaggerated knee-jerk reflex may indicate damage to the brain or spinal cord.
See also[edit | edit source]
References[edit | edit source]
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