Answer:
To expose the femur in a rat, the biceps femoris and gastrocnemius muscles are removed.
Step-by-step explanation:
The biceps femoris is a large muscle on the back of the thigh. It is responsible for extending the knee and flexing the hip. The gastrocnemius is a large muscle on the back of the calf. It is responsible for plantar flexing of the foot (pointing the toes down).
To remove these muscles, the skin and fascia are first incised on the back of the thigh and calf. The muscles are then carefully teased away from the bone using blunt dissection. Once the muscles are removed, the femur is exposed.