It is located between the 9th and 11th ribs. “The spleen . . . acts as a blood filter; it controls the amount of red blood cells and blood storage in the body, and helps to fight infection,” said Jordan Knowlton, an advanced registered nurse practitioner at the University of Florida Health Shands Hospital.
The incision is made on the left side of the abdomen, right under the rib area. Before removing the spleen, it is disconnected first from the blood supply and from the pancreas. After it is removed, the incision is closed using sutures and stitches. 
Aside from the left side of the abdomen, spleen pain may radiate towards other parts of the body, such as the shoulders, left side of the chest, back, and umbilicus. The pain rarely reaches the right side of the abdomen .This diagram with labels depicts and explains the details of Where Is Spleen.