Sensory Changes Due to Involvement of Nerve Roots (Radiculopathy) (Figs 9-1 to in Microsoft Office

Paint QR Code ISO/IEC18004 in Microsoft Office Sensory Changes Due to Involvement of Nerve Roots (Radiculopathy) (Figs 9-1 to

9-3 and Table 9-2) The surface innervation of the sensory nerve roots serves as one of the most useful and dependable guides to localization in neurology, and the several main dermatomes are known to all physicians Because of considerable overlap from adjacent roots, division of a single sensory root does not produce complete loss of sensation in

in the lower extremities, but loss or impairment of super cial or deep pain sense or of touch may be added in severe cases The feet and legs are most affected, much less often the arms and trunk The Romberg sign is prominent Frequently, atonicity of the bladder with retention of urine and trophic joint changes (Charcot joints) and crises of gastric pains are associated Also mentioned here are rare cases of congenital absence of all cutaneous sensation resulting from the lack of develpment of small sensory ganglion cells A similar but partial defect may be found in the Riley-Day syndrome (pages 464 and 1159) There are also forms of hereditary polyneuropathy that cause universal insensitivity Our colleague RD Adams has commented on an adolescent brother and sister that he observed with such a disorder

crepancy between the level of the lesion and that of the sensory loss, the latter ascending as the lesion progresses This can be understood if one conceives of a lesion as evolving from the periphery to the center of the cord, affecting rst the outermost bers carrying pain and temperature sensation from the legs Conversely, a lesion advancing from the center of the cord will affect these modalities in the reverse order, with so-called sacral sparing Hemisection of the Spinal Cord (Brown-Sequard Syndrome) In rare instances, disease is con ned to or predominates on one side of the spinal cord; pain and thermal sensation are affected on the opposite side of the body, and proprioceptive sensation is affected on the same side as the lesion The loss of pain and temperature sensation begins one or two segments below the lesion An associated spastic motor paralysis on the side of the lesion completes the syndrome (Fig 9-5) Tactile sensation is not greatly affected, since the bers from one side of the body are distributed in tracts (posterior columns, anterior and lateral spinothalamic) on both sides of the cord Syringomyelic Syndrome (Lesion of the Central Gray Matter) Since bers conducting pain and temperature sensation cross the cord in the anterior commissure, a lesion of considerable vertical extent in this location will characteristically abolish these modalities on one or both sides over several segments (dermatomes) but will spare tactile sensation (Fig 9-5) This type of dissociated sensory loss usually occurs in a segmental distribution, and since the lesion frequently involves other parts of the gray matter, varying degrees of segmental amyotrophy and re ex loss are usually present as well If the lesion has spread to the white matter, corticospinal, spinothalamic, and posterior column signs will be conjoined The most common cause of such a lesion in the cervical region is the centrally situated developmental syringomyelia; less common causes are intramedullary tumor, trauma, and hemorrhage

(Fig 9-5) See also Chap 44 Complete Spinal Sensory Syndrome With a complete transverse disruption of the spinal cord, the most striking loss is of motor power; most characteristic, however, is a loss of all forms of sensation below a level that corresponds to the lesion There may be a narrow zone of hyperesthesia at the upper margin of the anesthetic zone Loss of pain, temperature, and touch sensation begins one or two segments below the level of the lesion; vibratory and position senses have less discrete levels The sensory (and motor) loss in spinal cord lesions that involve both gray and white matter is expressed in patterns corresponding to bodily segments or dermatomes These are shown in Figs 9-2 and 9-3 and are most obvious on the trunk, where each intercostal nerve has a transverse distribution Also, it is important to remember that during the subacute evolution of a transverse spinal cord lesion, there may be a dis-