4. Spleen Ultrasound


There are numerous etiologies of splenomegaly, which can be broadly categorized as hematological (anemias, hematological neoplasms), hemodynamic (such as portal vein obstruction), infectious (especially viral), metabolic, neoplastic (non-hematological metastases), and owing to connective tissue disorders.

Since the etiologies are so varied, the associated manifestations will also vary widely from patient to patient. In rare cases, you may be able to appreciate a palpably enlarged spleen on physical exam. Patients may also complain vaguely of dull LUQ pain, fatigue (from anemia), and abdominal fullness.

A healthy spleen has a homogeneous echogenicity, smooth capsular contours, and a craniocaudal length no more than 12cm in an adult (although taller males may have a spleen up to 14cm long). Any larger, and your patient likely has splenomegaly.

Other findings in splenomegaly include a rounded inferior splenic surface – note above how the spleen sort of “hugs” the kidney and is convex inferiorly, whereas in the image below, the bottom has become concave with respect to the kidney, also dwarfing it in size.

splenomegaly ultrasound enlarged spleen
Severely enlarged spleen measuring 22cm, showing a more concave inferior surface, and massive dimension relative to the adjacent kidney.
Case courtesy of Dr Ian Bickle,
4. Spleen Ultrasound

Spleen Ultrasound Protocol

  • Place your probe in the 7th-8th intercostal space on the patient’s left side, with the indicator facing the patient’s head.
  • The spleen lies quite posteriorly, so you’ll want to be “knuckles-to-bed” to properly visualize it.
Spleen Probe and Hand Position Abdominal ultrasound
Spleen Ultrasound Probe Positioning. Notice “knuckles to the bed”

Visualize the spleen and adjacent left kidney.

  • If the ribs are casting a shadow over your window, try having the patient hold a deep breath to further widen the intercostal spaces. Align your probe obliquely with the intercostal space by rotating slightly clockwise.

Measure the spleen in the craniocaudal dimension. This is to evaluate for splenomegaly.

  • If you cannot see the superior and inferior boundaries of the spleen, estimate as shown below.
  • A normal spleen measurement is <12-14cm.
Spleen Ultrasound with Left Kidney Labeled
Ultrasound of Spleen
Spleen Ultrasound Measurement
Spleen Measurement
4. Spleen Ultrasound

Spleen Ultrasound

The spleen is imaged from the patient’s right side using ultrasonography. As with the liver, the spleen can be used as an acoustic window to assess other important structures, such as the aorta and IVC. Here, you’ll learn how to visualize the spleen and measure its craniocaudal length to evaluate for splenomegaly.