When the implant is inserted from the armpit (Transaxial incision) a pocket is made underneath the muscle to accept the implant. There are no seams or foreign objects which can be felt through the skin. back in the 80s and early 90s when surgeons switched from silicone to saline water, there was a minimally invasive procedure where the incision was made in the belly button and a tube was snaked under the skin to the desired location then the deflated implant was deployed and filled to the desired size and firmness. They looked fake, but they were cheaper and quicker healing time and saline was safe but many of them ripped and or leaked with physical trauma, exercise, issues with the inflation valve failing. So the procedure changed and the implants were improved. back to a sealed gel implant now heavily protected by the muscle. the woman could do aerobics, strength training, freeweights, body sculpting and any vigorous activity without worrying that she might bust her balloons. Yes I work for a cosmetic surgeon and I have learned a few things over the years.
In the words of My dear old friend Connie Reshey put it " They may not be real, but theyre real nice and cost real money."