REIDER PART 255

Chapter 8 Cervical and Thoracic Spine 315

respond to the dermatome associatcd with that ncrve root. A nonradicular sensory loss suggests a morę peripheral nerve injury; the involved area is morę diffuse and overlaps several dermatomes. A glove or stocking distribution of sensory dysfunction signifies a circumfer-ential sensory deficit in the entire portion of the involved limb distal to a certain point. Conditions that may be associated with a glove or stocking sensory deficit include diabetic peripheral neuropathy, retlex sympathetic dys-trophy, and nonorganic disordcrs.

Light Touch. AU sensory testing is carried out with the patients eyes closed. For screening purposes, light touch can be tested by lightly stroking the patients skin with a soft object, such as a smali paintbrush, a cotton wisp, or a tissue (Fig. 8-28A). The examiner strokes the area in ąuestion as well as adjacent areas and asks the patient to acknowledge each touch. In this manner, the examiner can gradually delineate an area that is anesthetic or hypoesthetic. The abnormal area can be marked on the patient and compared with diagrams of dermatomes and the sensory distribution of peripheral nerves. For morę precise testing, special filaments madę cxpressly for this purpose may be used.

Sharp-Dull Discrimination. Sharp-dull discrimination testing may be used to confirm the results of a light touch examination. In this case, the patient is asked to identify whether the area being examined is being touched with the sharp or duli end of a safety pin (Fig. 8-28B and C). This distinction should normally be an easy one for the patient to make; in an area of diminished sensation, the patient has difficulty distinguishing between sharp and duli. Vibration Sense. Vibration sense can be tested using a tuning fork of 256 Hz over bony prominences such as the humerał epicondyles or the radial styloid. The examincr

Figurę 8-28. Sensory testing. A, Light touch. B, Sharp. C, Duli.