Which nerve is NOT innervated by the femoral nerve?

The long saphenous nerve is not innervated by the femoral nerve, which is why this choice is correct. The long saphenous nerve actually arises from the femoral nerve but serves a different function. Primarily, it is a sensory nerve that provides sensation to the skin on the medial aspect of the leg and foot. Its role is distinct from the motor innervation provided directly by the femoral nerve to the quadriceps group of muscles and other structures.

In contrast, the other options represent structures that are innervated by the femoral nerve. The saphenous nerve, a branch of the femoral nerve, contributes sensory innervation to the skin of the medial leg. The vastus nerve, which is part of the vastus group of muscles, is also directly innervated by the femoral nerve, allowing for motor control. Similarly, the pectineus muscle receives its innervation from the femoral nerve, facilitating its role in hip flexion and adduction. Understanding the distinctions between sensory and motor components as well as the specific roles of these nerves aids in grasping the anatomy and functions relevant in surgical practice.