Using the lateral ultrasound approach, you can assess the size, texture (parenchymal echogenicity), and surface characteristics (capsular contour) of the liver (Rumack). Importantly from this view, the liver also offers a useful acoustic window to view clinically important structures such as the aorta, IVC, hepatic veins, and portal vein.
Position your probe on the patient’s right in the mid-axillary line at the 10th-11th intercostal space, with the indicator facing the patient’s head. If possible, ask your patient to hold their right arm above their head to widen the intercostal spaces.
Visualize the diaphragm, liver, and right kidney in the long-axis.
- Tip: if the ribs are blocking a good view, ask the patient to hold a deep breath to further widen the intercostal spaces. Try rotating your probe obliquely to align with the intercostal spaces as well.
Assess the liver’s echogenicity and capsular contour.
- Normally, the liver has a homogenous echogenicity similar in brightness to the renal cortex (Rumack). Check for notable variations, such as increased or decreased echogenicity, masses, or lesions.
- The liver should have a smooth capsular contour, again similar to that of the kidney. Note any marked coarseness or nodularity.
Measure the liver span in the craniocaudal dimension.
- Once you have visualized the structures listed above, freeze the image and measure the liver span from the diaphragmatic surface to the inferior border, as pictured below.
- Tip: sometimes, the ultrasound window is too narrow to capture the liver’s diaphragmatic surface and tip together on the screen. Estimate, to the best of your ability, where either of these surfaces would end if you could see them both, and place your calipers at your best guess.
