哪种翻译更好

The iliopsoas muscle originates from the iliac fossa (iliacus muscles) and the upper lumbar spine (psoas major muscle) and inserts on the lesser trochanter of the femur. This joined muscle is innervated by anterior rami of lumbar nerve roots (L1–L3) as well as the femoral nerve (L2–L4). The muscle primarily flexes the hip and is active during sitting and standing.

髂腰肌起源于髂窝（髂肌）和上腰椎（腰大肌），止于股骨小转子。该肌由腰神经根前支（L1～L3）和股神经（L2～L4）支配。

1.主要作用是屈髋，在坐姿和站姿时激活此肌肉。

2.主要作用是在坐姿和站姿时屈髋。