The spleen is a reddish and soft largest single mass of lymphatic tissue that occupies the left upper part of the abdomen between the stomach and the diaphragm. It is oval shaped and has a notched anterior border. It lies just beneath the left half of the diaphragm close to the 9th, 10th, and 11th ribs. The long axis lies along the shaft of the 10th rib, and its lower pole extends forward only as far as the midaxillary line and cannot be palpated on clinical examination.
The spleen is surrounded by peritoneum which passes from it at the hilum as the gastrosplenic omentum (ligament) to the greater curvature of the stomach (carrying the short gastric and left gastroepiploic vessels). The peritoneum also passes to the left kidney as the splenicorenal ligament (carrying the splenic vessels and the tail of the pancreas).