Please note that the spinal roots for L2 through S5 all descend in the cauda equina and injury to these roots would disrupt sensory and motor fibers from these segments. Strictly speaking, the spinal roots are part of the peripheral nervous system as opposed to the spinal cord. Peripheral nerves are supposed to be able to regenerate to some extent.
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same quantity. Any other value of that quantity can be expressed as a simple multiple of the unit of measurement. For example, length is a physical quantity. The metre is a unit of length that represents a definite predetermined length. When we say 10 metres (or 10 m), we actually mean 10 times the definite predetermined length called metre.
We can measure how big things are, how warm they are, how heavy they are, and lots of other features as well. Units of Measurement provide standards for our comparisons, so that the numbers from our measurements refer to the same thing. For example, the metre is a standard unit to measure length.he property of the thing being measured is given as a number of units of measure. The number only has sense when the unit of measurement is also given. For example, The Eiffel Tower in Paris, France is 300 meters tall. That is, the distance from the top to the bottom of the Eiffel Tower is 300 meters.