Lesson 16 (Part 2) Flashcards
What is the normal volume for the spleen?
60-200mL
What is the average weight of the spleen?
<150g on autopsy
- 80-300g average
- depends on age/gender
What happens to the spleen with increasing age?
Its size and weight decreases
- even smaller in women
What is the echogenicity of the spleen compared to the liver and the left kidney?
Hyperechoic
What is the echotecture of the spleen?
The parenchyma is homogenous
What is normal to see in the spleen as a patient ages?
Calcified arteries
What level do you measure the spleen in sagittal?
At the level of the hilum
- longest point
Is the spleen routinely scanned in an abdomen exam?
Yes
What are the 2 positions you can scan the spleen in?
- Supine
- left intercostal coronal approach - Right lateral decubitus
What are common maneuvers when scanning the spleen? (3)
- Small breath in
- Large breath in
- Shallow breathing
- or no breathing
What can help with identifying the location of the hilum? (2)
- Splenic vein
2. Splenic artery
Why is scanning intercostally difficult?
Have to be directly in between the ribs, otherwise we will see shadow in our image
Why is scanning the spleen superiorly difficult?
Because of the lungs
- cant see through air
Why is scanning subcostaly not always possible?
Gas
What are 3 pitfalls when scanning the spleen?
- Ribs
- Gas
- close to the stomach - Lungs/diaphragm
What structures can the spleen get confused with?
The liver
- elongated left lobe
What other modalities can help to further demonstrate challenging cases related to the spleen? (2)
- CT
2. MRI
What cells does the spleen arise from?
Mesenchymal cells
Where are mesenchymal cells located?
Between layers of the dorsal mesentery
What do mesenchymal cells differentiate to form? (2)
- Splenic pulp
2. Splenic capsule
What does the base of the dorsal mesentery fuse with?
The posterior peritoneum
What does the fusing of the base of the dorsal mesentery and the posterior peritoneum form?
The splenorenal ligament
What are 5 examples of normal variants/congenital anomalies?
- Accessory spleen
- Asplenia
- Polysplenia
- Wandering
- Ectopic
What is the most common normal variants/congenital anomalies?
Accessory spleen
What is accessory spleen also known as?
Splenule
Accessory spleen
Homogenous isoechoic mass similar to the spleen
Where is the splenule typically found? (2)
- At the hilum
2. Inferior border of the spleen
Asplenia
Complete absence of the spleen
- rare
- may occur as part of a major congenital abnormality
Polysplenia
Multiple small accessory spleens
Wandering spleen
Migrated from its normal location in the LUQ
What happens the the dorsal mesentery with a wandering spleen?
It fails to fuse properly with the posterior peritoneum
What does the wandering spleen lack?
Supporting ligaments
- doesnt fuse so it doesnt have proper ligaments
Ectopic
The spleen is located in the abdominal cavity outside of where it should be
