**3. Detection of allodynia and expansion**

To detect allodynia, a cotton-tipped applicator is slowly drawn down from the midclavicular line toward the pubic region along the imagined border of the rectus abdominus muscle. It is necessary to start the test outside the area of allodynia. Starting within will not detect the necessary changes. As the applicator is positioned, the woman is asked to note if there is any sudden change in sensation or the onset of a sharp pain. When this is announced, the level is marked off with a body marker. An example of two small areas of allodynia containing trigger points associated with the T12 anterior cutaneous nerves is shown in **Figure 3**.

An extreme example of severe chronic pelvic pain demonstrates how large the area of allodynia can become—this degree is unusual (**Figure 4**). The delineation of allodynia that is marked off with a pen can stimulate spinal activity such that there is an almost immediate shift in the borders of allodynia (**Figure 4**). These shifts in the levels of sensation correspond to "jumps" taking place in the spinal cord, segment by segment.

**Figure 4.**

*An example of allodynia expansion upward by dermatome with each test for allodynia in a woman with severe pelvic pain.*
