dorsal root of sac

例句：

1. 1. The dorsal root of the spine is responsible for supporting the body's weight.
   脊柱的背根负责支撑身体的重量。
2. 2. The dorsal root of the spinal cord is crucial for sensory perception in the lower body.
   脊髓的背根对下肢的感觉感知至关重要。
3. 3.During locomotion, the dorsal root sends signals to the brain to control the movement of the limbs.
   在运动过程中，背根向大脑发送信号以控制肢体的运动。