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Portrait of Spleen

Anatomy · Organs & viscera

Spleen

Largest lymphoid organ

Left upper abdomen · lymphatic system

The spleen is a soft, purplish, fist-sized organ tucked under the left ribs in the left hypochondrium, against the diaphragm. It lies at about the level of the 9th to 11th ribs, with the stomach in front, the left kidney behind and below, and the tail of the pancreas at its hilum. It filters blood, removes old red cells and mounts immune responses, but it can be removed with survivable consequences.

How to spot them

  • ▸A wedge- or crescent-shaped organ with a notched upper border, lying against the diaphragm beneath ribs 9 to 11 on the left
  • ▸Its long axis follows the 10th rib; it is normally hidden under the ribs and cannot be felt unless enlarged
  • ▸Its concave visceral surface has impressions from the stomach, left kidney, splenic flexure of the colon and tail of pancreas
  • ▸The splenic artery and vein enter and leave at its hilum

What to know

The mnemonic 1, 3, 5, 7, 9, 11 describes this organ's dimensions, weight and position under the ribs

Spleen — 1 inch thick, 3 wide, 5 long, weighing 7 ounces, between ribs 9 and 11.

A soft organ with a notched upper edge that lies against the diaphragm under the left ninth to eleventh ribs

The spleen, in the left hypochondrium.

Its surface bears impressions from the stomach, the left kidney, the splenic flexure and the tail of the pancreas

The visceral surface of the spleen and its gastric, renal, colic and pancreatic relations.

Tearing of this organ in blunt trauma can send pain to the tip of the left shoulder, known as Kehr's sign

Ruptured spleen — diaphragmatic irritation refers pain via the phrenic nerve.

Fed by the largest branch of the coeliac trunk, a tortuous artery running along the top of the pancreas

The splenic artery, which supplies the spleen.

Removing it leaves a person open to overwhelming infection by encapsulated bacteria and calls for vaccines

Post-splenectomy infection; the spleen is the main site of filtration of encapsulated organisms.

Its tissue is divided into red pulp, where old red cells are broken down, and white pulp, where lymphocytes gather

The red and white pulp of the spleen.

Key ideas

  • Red pulp filters the blood, destroying worn-out red cells and storing platelets and iron; white pulp is lymphoid tissue that makes antibodies against blood-borne pathogens.
  • Because it is lightly protected, it is vulnerable to fractures of the lower left ribs and is one of the most commonly injured abdominal organs in blunt trauma.

Quick-fire facts

  • •It is the largest organ of the lymphatic system, typically around 12 cm long and 150 g, but sizes vary.
  • •It lies between the fundus of the stomach and the diaphragm, in the left hypochondrium, under ribs 9 to 11.
  • •It is intraperitoneal, held by the gastrosplenic ligament (to the stomach) and the splenorenal ligament (to the left kidney).
  • •The splenic artery arises from the coeliac trunk; the splenic vein joins the superior mesenteric vein behind the neck of the pancreas to form the portal vein.
  • •An enlarged spleen (splenomegaly) descends towards the right iliac fossa, and becomes palpable below the left costal margin.
  • •Accessory spleens (splenunculi) occur in roughly 10 per cent or more of people, most often near the hilum.
  • •Kehr's sign is referred pain to the left shoulder tip caused by blood irritating the diaphragm.
  • •The word spleen was once a synonym for melancholy and ill humour, from the old idea that it produced black bile.

Drill it — 8 cards

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Sources