Anatomy of the spleen

The spleen is an supramesocolic organ located in the left hypochondrium . The spleen is a lymphoid organ whith two roles:

* Regulating the formation and destruction of the formed elements of the blood.
* Immunity of the body.

Description of the spleen

The spleen is compared to a wholesale coffee bean which presents two faces, two sides, two poles.

The dorso-lateral face of the spleen is highly convex, and is in contact with the right diaphragmatic dome.

The ventro-medial portion surface of the spleen is almost flat and oriented in ventral, medial and caudal. The spleen has a depression in its middle part, the hilum of the spleen (where all Splenic vessels end). In the back of the depression is a small dimple, the dimple kidney. In front there is a different dimple, the gastric dimple.

The dorsal edge of the spleen is regular and very curvy. The ventral edge of the spleen is erratic (important indented clinic aspect). The skull pole of the spleen is rounded.

The caudal pole of the spleen is often triangular and is called colic surface.

The rate measuring 12 cm long, 8 cm wide, 4 cm thick, weighs 200g (adult). There may be some incidental or supernumerary rates of 1 cm in diameter, located in the épiploon gastrosplenic or in the large ommentum.

It can be partially splénectomized in anemic people; if a supernumerary spleen is forgotten, it will hypertrophy and pathology will resume. The spleen is frequently injured during trauma, it is fragile.

Relations of the spleen

Relations of the spleen with the peritoneum

The spleen is surrounded by the visceral peritoneum.
The hilum presents two omentums : the lienorenal ligament and the gastrosplenic ligament.

Relations of the spleen with the surrounding organs

The dorso-lateral surfaceface is related to the diaphragm and with the forward ribs.

The spleen is projected at the height of the 10th rib.

The spleen ventro-medial surface is related to:

* Vessels and sometimes the tail of the pancreas at the hilum.
* Kidney and suprarenal gland left behind the hilum
* The fundus and body of the stomach in front of the hilum
* The higher pole is in relation to the left edge of the esophagus and the fundus.
* The lower pole is related to the colon. (The left colic corner).

At the left corner of the colon there is a ligament relatively thick , the phreno-colic ligament. It is considered as a suspensor element of the spleen.

The ventral edge of a normal spleen does not reach beyond the costal edge, it is not palpable but percutable up to the 10th rib. It will become palpable when there is a splenomegaly: its belly edge feature can be felt.

Vascularisation of the spleen

The arteries

The splenic artery comes from the celiac artery up to T12. Its course winds supra-pancreatic then retro-pancreatic and pre-pancreatic. It is divided into two main branches in the hilum of the spleen. It provides collaterals:

short vessels of the stomach
artery for the body and tail of the pancreas
left epiploic artery

Veins

There are two splenic arteries therefore two streaks that will merge at the exit of the hilum to form the splenic vein. It is retro pancreatic and anastomoses with inferior mesenteric vein to form the spleno-mesaraic trunk.