Sensory thresholds at different sites of the foot: a valuable reference for neurologic examinations

STUDY DESIGN: Prospective healthy volunteer study for sensory thresholds. OBJECTIVES: The aim of this study was to test sensory thresholds at different sites of the foot to provide a reference for diagnosis and neurologic classification. SETTING: A university hospital for the research and clinical practice of rehabilitation. METHODS: Thirty healthy volunteers were recruited, and quantitative sensory testing was performed on three sites of the foot (medial malleolus (for the L4 dermatome), dorsum of the foot at the third metatarsal phalangeal joint (for the L5 dermatome) and lateral heel (for the S1 dermatome)). First, cold sense, warm sense, cold pain and hot pain were tested. Second, a monofilament tactility test was performed. Finally, a physical examination for sensation was performed. RESULTS: All of the thresholds for the medial malleolus were significantly different from those for the dorsum of the foot at the third metatarsal phalangeal joint and lateral heel, whereas no significant difference existed between the values for the dorsum of the foot at the third metatarsal phalangeal joint and lateral heel. CONCLUSION: The sensory threshold of the human medial malleolus may be significantly different from those of adjacent sites of the foot. Thus, the results obtained from physical examination of sensory thresholds of the medial malleolus should be used modestly as a reference, but should not be used for diagnostic or classification purposes.