Doctors will sometimes test the patellar reflex by striking…

Doctors will sometimes test the patellar reflex by striking the patellar tendon with a reflex hammer.  This causes the tendon to stretch, which sends an impulse along a sensory neuron to the spinal cord.  Within the spinal cord, the sensory neuron synapses directly on a motor neuron.  The motor neuron sends a signal back to the quadriceps muscle attached to the tendon that was struck, causing it to contract.  This shortens the patellar tendon. Based on this description, select ALL options that describe this reflex: