Is the area soft or hard? Heat present? Flinching when palpated? So this is sudden and was not present prior? How long have you owned her and what type of work are you doing with her?
Heave line is where abdominal muscles are. Flank back towards pecs but not pecs. 22 on the photo in OP is where the heave line shows. It shows where muscle 22 meets the white portion also labeled 22.
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