The tendons of the sartorius, gracilis, and semitendinosus muscles combine and expand to form the pes anserinus. These muscles combine at the medial boarder of the tibial tuberosity.

Fun fact: the pes anserinus may be used in the surgical repair of the knee joint’s anterior cruciate ligament.

The rectus femoris is an anterior muscle of the thigh, and is a member of the quadriceps. It inserts at the base of the patella at the tibial tuberosity. Like all the quadriceps it helps extend the leg and is innervated by the femoral nerve. 

The quadriceps muscle group is a large group of muscles in the anterior thigh. The quadriceps consists of the following muscles: rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. (Fun fact: there is also a fifth quadriceps muscle that is rarely taught called the articularis genus.)

The quadriceps muscle group is the great extensor muscle of the knee and extends the leg. The femoral nerve innervates all the muscles of the quadriceps group. 

The adductor brevis muscle is located in the medial compartment of the thigh, meaning we are looking for a nerve in that location. Of the answer choices, only the femoral and obturator nerves are located in the thigh, whereas the tibia and common fibular nerves are located in the leg. Of the femoral and obturator nerves, we are looking for the more medial nerve, meaning the obturator nerve is the correct answer.

For this question, we are looking for a muscle that is located in the lateral compartment of the thigh. In addition, this muscle should contract when the thigh is either abducted or medially rotated. The correct answer is the tensor fasciae latae which is the only muscle of the choices that fits these categories.

Both the superior gemellus and the obturator internus muscles are innervated by the same nerve. The nerve that innervates the obturator internus is easy to remember because the nerve and the muscle have the same name. That means the obturator internus nerve is the correct answer.

For this question, we are looking for a muscle that lies in the posterior, superficial compartment of the leg. This eliminates the gracilis muscle, leaving the planters, gastrocnemius, and soles muscles. The correct answer is the plantaris muscle which is a small muscle in the posterior compartment of the leg that has a long tendon and little to no function. Both the gastrocnemius and soleus muscles are larger and more important in walking and running.

Because this muscle has its origin on the ischial tuberosity of the pubic bone and inserts into the medial condyle of the tibia, it is a muscle in the thigh. Of the following answer choices only the semimembranosus and the gracilis muscles are located in the thigh. However, its attachments also show that this muscle will be in the posterior compartment of the thing, meaning the correct answer is the semimembranosus muscle.

The correct answer is the iliacus. This is the only one of these muscles that is located in the hip region. The intercostals are between each of the ribs and the pectineus and gracilis muscles in the thighs.

We are looking for a muscle in the posterior compartment of the thigh. This means that the muscle will be on the back of the leg, between the pelvis and the kneecap. The correct answer is the gracilis muscle, which unlike the other three is located in the anterior compartment of the thigh.

Extensor muscles located in the deep, posterior compartment of the leg are responsible for flexing the toes. In this case, the correct answer is the extensor digitorum longus because it controls the 2nd through 5th digits in the feet. We can infer this by looking at the word "digitorum", meaning digits, as in fingers or toes. The extensor hallucis longus extends the first digit in the lower extremity (hallux) and dorsiflexes the foot. The tibialis anterior is the strongest dorsiflexor of the foot.