The combination of the clinical data, MRI imagery combined with the knowledge of localization, and pathophysiological mechanisms leads to the diagnosis of syringomyelia. The loss of pain and temperature sensation with preservation of sensation of vibration and proprioception is due to the destruction of the fibers from the spinothalamic tract which cross in the anterior commissure. This dissociated sensory loss combined with lower motor neuron signs at the level of the lesion and upper motor signs below the lesion is characteristic of syringomyelia.