Underneath our skin is a much tougher layer called the fascia. This fascia is responsible for keeping our insides inside us. After an operation on your belly (open surgery or key-hole) your surgeon will have stitched or sutured closed the fascia layer before stitching the skin closed. If the fascia layer doesn't heal completely, a hole can develop allowing the contents of your belly to bulge through. This is called an incisional hernia.