Anatomy, Abdomen and Pelvis, Spleen

The spleen is the largest organ of the lymphatic system positioned between the fundus of the stomach and the diaphragm in the left hypochondriac region of the abdominal cavity, relatively below the left costal margin between the ninth and 11th ribs. The spleen is spongy and appears reddish purple on account of it being densely vascularized. A healthy spleen is usually not palpable in most individuals. It is encased in a weak outer connective tissue capsule which allows for protection and also the expansion of the organ and is subdivided into many smaller internal sections termed lobules. The spleen has an anterior and posterior segment and rests on the upper pole of the left kidney and tail of the pancreas. The spleen has 3 distinct borders: superior, inferior, and intermediate. The superior border of the spleen has a notch on the anterior end. The spleen has 2 surfaces, the visceral and diaphragmatic. The latter surface is convex and smooth, whereas the former surface is concave and irregular with several imprints. The most concave imprint on the spleen is a resultant of the fundus of the stomach. The left kidney leaves an imprint on the intermediate and inferior borders. The colic imprint is from the splenic flexure of the colon. The tail of the pancreas leaves an impression between the hilum and colic impression sites. The splenic hilum is found on the inferomedial aspect of the gastric imprint. The splenic hilum contains nerves, splenic vessels, and also contains attachments for the splenorenal and gastrosplenic ligaments. It is roughly the size of an individual’s fist, measuring about 10 cm to 12 cm (about 3.94 to 4.72 in) and weighing about 150 g to 200 g (about 5.29 oz to 7.05 oz).