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Throbbing of blood vessels in the abdomen or sometimes palpable pulse could be a sign of an underlying aneurysm
or it's branches. A block or stenosis of arteries could also cause throbbing sensation . Though rarely such finding can be seen in very thin individuals , it's advisable to get an ultrasound
abdomen done to rule out any blood vessel disorders. In early stages there could be no symptoms or pain but still at least a clinical evaluation by your doctor is mandatory.Many times a small or insignificant abnormality might not require any treatment but exact treatment and prognosis can only be commented after confirmed diagnosis.
Hope I have answered your query.
Wishing you good health.