Internal organ massage, also known as visceral massage or visceral manipulation, releases tension that can cause abdominal pain, back pain, hip-or-leg pain, migraine, from the internal organs. The muscular organs include the small intestine, large intestine, stomach, bladder, gall bladder, heart, spleen and uterus. When the visceral muscles are relaxed, tension is released, posture improves, the abdomen and low back flattens, the pelvis lifts forward, the body lengthens, the chest lifts and breathing deepens.
(Source: Berkeley Massage Therapy for Pain Relief, bodytechnician.com)