Deer shed their antlers each year.

每年都蜕。

In this case, a large "staghorn" calculus (so named because the prominent projections of the stone into the calyces resemble deer antlers) was present that filled up the pelvis and calyceal system.

在这个病例中，有一个状结石（如此命名是因为结石突入到肾盏内与很相似）填满了肾盂肾盏。