Answer: if the upper leg muscles were damaged, (You would not be able to extend the leg straight).
Explanation:
The upper leg muscles, which can also be called the thigh, are made up of three sets of muscles which include:
--> the hamstring muscles: These are located at the BACK of the thigh. They are made up of three long muscles which includes the semimembranous muscle, the semitendinosus muscle, and the biceps femoris muscle.
--> the quadriceps muscles: They are located at the FRONT of the thigh. They consists of four individual muscles which includes the three vastus muscles and the rectus femoris.
--> the adductor muscles: They are located at the medial compartment of the thigh and is consist of the following muscles: gracilis, obturator externus, adductor brevis, adductor longus and adductor magnus.
The quadriceps, hamstrings and adductor muscles work together to straighten (extend) and bend (flex) the leg. Therefore when there is damage to the upper leg muscles, you would not be able to extend the leg straight.