The spleen (Read more!) is positioned in the left upper quadrant (left hypochondriac region) of the abdomen, lying posterolateral to the stomach (gaster). It is located between the fundus of the stomach (fundus gastris) and the left hemidiaphragm (hemidiaphragma sinistrum) at the level of ribs nine to eleven (costae IX - XI).

• Medial and posterior to the spleen lies the left kidney (ren sinister) (Read more!) and left adrenal gland (glandula suprarenalis sinistra) (Read more!).
• In addition, the tail of the pancreas (cauda pancreatis) is found adjacent to the medial aspect of the spleen.
• Lateral to the spleen are the rib cage (cavea thoracis), phrenicocolic ligament (lig. phrenicocolicum), and the anterolateral abdominal wall muscles (mm. abdominis anterolaterales).
• The diaphragm (diaphragma) (Read more!) is superior to it, while the left colic flexure (flexura sinistra coli) (Read more!) is positioned inferior. Hence, the left colic flexure is also called the splenic flexure (flexura splenica coli).

Usually, the spleen does not extend beyond the left costal arch (arcus costalis sinister), and it is not palpable in a healthy individual during physical examination. It can only be palpable if it extends beyond the left costal arch. In that case, an enlarged spleen is called splenomegaly (splenomegalia).

Note: 10 to 30% of the population have an accessory spleen (splen accessorius). An accessory or supernumerary spleen is a benign condition in which splenic tissue is found outside and separately from the spleen. Usually, a person has one to six accessory spleens. Their size can vary, but most often, they do not exceed 0.4 inches (1 centimeter). In most cases, the accessory spleen is found in the splenic hilum (hilum splenis) or near the tail of the pancreas (cauda pancreatis). However, it can also be positioned within the gastrosplenic (lig. gastrosplenicum) or splenorenal (lig. splenorenale) ligaments or the stomach wall, intestinal wall, greater omentum (omentum majus), mesentery (mesenterium), pelvis (pelvis) or even scrotum (scrotum).