Anatomy, Physiology, & Congenital Anomalies

What is the spleen?

Encapsulated organ located in LUQ

What is the normal size of the spleen?

1. Length: < 12 cm

2. Width: < 8 cm

3. Heigh: < 4 cm

4. Splenic volume index (SVI): 8 - 35

What is a retrorenal spleen?

When inferior portion of spleen is located posterolateral to upper pole of left kidney

What is considered to be the most tortuous vessel in the human body?

Splenic artery

What is the splenic artery?

Vessel that travels through splenorenal ligament to supply spleen, pancreas, and fundus of stomach with blood

(T/F) The spleen is at great risk of permanent damage with infarction.

True; Intrasplenic arterial circulation does not communicate with each other and eliminates possibility of collateral formation

What is the splenic vein?

Vessel that originates at splenic hilum and drains stomach, spleen, and pancreas

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Splenic vein

What is the largest organ of the reticuloendothelial system (RES)?

Spleen

What is splenic tissue composed of?

1. Red pulp (85%): Venous sinuses filled with blood and cords of splenic tissue

2. White pulp (15%): Clusters of lymphatic tissue

What are the functions of the spleen?

1. Blood filtration

2. Blood production

3. Blood destruction

4. Blood storage

What is hypersplenism?

Overactive spleen that removes too many blood cells from circulation due to cirrhosis, TB, Gaucher disease, and lymphoma

What is hyposplenism?

Underperforming spleen due to sickle cell anemia or celiac disease

What is extramedullary hematopoiesis?

Blood cell production that occurs outside of bone marrow

What is fetal hematopoiesis?

When spleen produces RBCs and WBCs

What is adult lymphopoiesis?

When spleen produces RBCs and WBCs

What is leukopenia?

Decreased WBCs

What is leukocytosis?

Increased WBCs

What is anemia?

Decreased RBCs

What is polycythemia?

Increased RBCs

What is thrombocytopenia?

Decreased platelets

What is thrombocytosis?

Increased platelets

What is hematocrit?

Number of RBCs in blood

What is the sonographic appearance of the spleen?

1. Isoechoic or hyperechoic to liver

2. Homogenous

What is situs ambiguous or heterotaxia?

When abdominal organs are in an disorganized rearrangement

What is asplenia?

Form of heterotaxia in which there is a congenital absence of spleen that is associated with double right-sidedness

What is polysplenia?

Form of heterotaxia in which there are multiple spleen that is associated with double left-sidedness

What is the most common congenital anamoly of the spleen?

Accessory spleen or splenule

What is an accessory spleen or splenule?

Mini splenic structure located near splenic hilum

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Accessory spleen or splenule

What is an ectopic or wandering spleen?

Weak splenic ligaments lead to spleen migrating to unusual locations

What is hereditary hemolytic anemia?

When one or more of genes that control RBC production are abnormal

What is sickle cell anemia?

Abnormal hemoglobin and crescent or sickle shaped RBCs

What is acquired hemolytic anemia?

Excessive destrucion of normal RBCs due to infection or medication or hypersplenism

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Splenic cyst

What is an epidermoid cyst?

Cyst filled with keratin substance

What is the most common type of abdominal branch aneurysm?

Splenic artery aneurysm

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Splenic aneurysm

What is a subscapular hematoma?

Blood collection that forms between capsule and splenic pulp

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Subscapular hematoma

What is a perisplenic or intraperitoneal hematoma?

Blood collection inside peritoneal cavity due to splenic rupture

What is an intraparenchymal hematoma?

Blood collection within parenchyma

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intraparenchymal hematoma

What is splenic rupture?

Abscensce of normal spleen in LUQ due to trauma

What are the causes of spontaneous splenic rupture?

1. Hepatitis A

2. Malaria

3. Cytomegalovirus

4. Mononucleosis

5. HIV

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Splenic rupture

What is a splenic infarct?

Areas of tissue death in spleen

What is the sonographic appearance of splenic infract?

1. Hypoechoic wedge shaped area

2. Bring band sign seen as echogenic linear-shaped bands within infarct

3. Avascularity

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Splenic infarct

What is congestive splenomegaly or Banti syndrome?

Excessive pooling of blood in splenic tissue due to portal HTN, CHF, and splenic vein thrombosis that causes splenomegaly

What is the sonographic appearance of congestive splenomegaly or Banti syndrome?

1. Splenomegaly

2. Splenic varices

3. Increased splenic artery RI

What is the most common cause of splenomegaly?

Portal HTN