Neurology Edited by Professor Emeritus Desire' Dubounet, IMUNE

After the individual values for loss of function due to sensorydeficit, pain, or discomfort, and loss of function due to loss of strengthhave been determined, the impairment to the part of the body or to thewhole person is calculated by combining the values using the CombinedValues Chart.Determination of impairment: The order in which permanentimpairment of the peripheral spinal nerves will be discussed is (1) thespinal nerve roots; (2) the lumbosacral plexus; and (3) the named spinalnerves.The Spinal Nerve RootsThe roots of the spinal nerves can be impaired by various diseases or byinjuries that produce partial or complete, and unilateral or bilateral, effects.The degree of permanent impairment resulting from a spinal nerve rootdysfunction would be reflected in the loss of function of the named spinalnerves having fibers from the specific nerve root. Since the named spinalnerves have fibers from more than one root, a dysfunction affecting twoor more roots that supply fibers to the same nerves usually will be moreimpairing than a combination of the individual root impairment values (seesection on lumbosacral plexus).Table 45 provides values for the spinal nerve roots that are mostfrequently involved in the permanent impairment of the lower extremity.The values given are for unilateral involvement only. Where there isbilateral involvement, the values should be combined, using the CombinedValues Chart at the end of the book.Values for impairment of a specific spinal nerve root that is not mentionedshould be determined by taking into consideration the values that aresuggested for a nerve having fibers from the specific nerve root. Thereader should refer to the "The Named Spinal Nerves'The Lumbosacral PlexusImpairment due to lumbosacral plexus injury or disease can be determinedby evaluating the various functions that are lost. The major nerves of thelower extremity and of the pelvic girdle are derived from the lumbosacralplexus (Figure 80). Thus, that plexus involves not only the lowerextremity, but also bowel, bladder, and reproductive functions and trunkstabilization. Percentages for unilateral lumbosacral impairments are givenin Table 46.The Named Spinal Nerves