Neurons are the individual cells that make up nerves.
Most motor neurons in your spinal cord are upper motor neurons. Lower motor neurons start in the front of your gray matter and leave your spinal cord in your spinal nerves.
Because your cauda equina is made of spinal nerves it has lower motor neurons.
Injuries to your spinal cord typically have upper motor neuron injuries or lesions. Injuries to your conus medullaris, the end of your spinal cord, can have a mix of upper and lower motor neuron lesions. Injuries to your cauda equina have lower motor neuron lesions.
Your upper motor neurons control your lower motor neurons. Your lower motor neurons control the reflexes of your bladder, bowel, sexual organs, and muscles. Whether your injury has damaged upper motor neurons, lower motor neurons, or both means a lot in the function of your bladder, bowel, and sexual organs.
For example, in an upper motor neuron lesion your bladder will likely have reflex contractions.
In a lower motor neuron lesion your bladder will have no tone, and will probably not be able to contract. Knowing what kind of lesion you have allows you to work with your doctor and find the best lifestyle changes for yourself.