Final answer:
An adrenal hemorrhage typically appears as a hypoechoic mass on ultrasound, which means it looks darker than the surrounding tissue due to fewer echoes.
Step-by-step explanation:
On ultrasound (U/S), an adrenal hemorrhage typically appears as a hypoechoic mass. This means that the hemorrhage will have fewer echoes compared to the surrounding tissues, therefore, it appears darker on the ultrasound image. The appearance might vary depending on the age of the hematoma. In the acute phase, the hemorrhage can contain more echogenic or mixed echogenic elements due to clot formation. Over time, as the hemorrhage evolves, the hematoma may become more anechoic or hypoechoic as the clot liquefies.