Which nerve innervates the adductor longus and gracilis muscles, providing sensation to the medial thigh?

• A. Femoral nerve
• B. Anterior branch of the obturator nerve
• C. Posterior branch of the obturator nerve
• D. Inferior gluteal nerve

Answer: (B)

The adductor longus and gracilis muscles are primarily innervated by the obturator nerve, specifically its anterior branch. This branch is responsible for motor innervation to the adductor muscles, enabling hip adduction. In addition, the obturator nerve also contributes to sensory innervation for the skin over the medial aspect of the thigh, which further emphasizes its role in this region.

The femoral nerve mainly supplies the muscles of the anterior compartment of the thigh, such as the quadriceps, and does not have a significant role in innervating the adductor muscles. Similarly, the posterior branch of the obturator nerve innervates the adductor magnus but is not responsible for the innervation of the longus and gracilis. The inferior gluteal nerve primarily innervates the gluteus maximus and is not involved in the innervation of the medial thigh muscles. Thus, the anterior branch of the obturator nerve accurately reflects the innervation responsible for both the motor function of the adductor longus and gracilis as well as the sensory function in the medial thigh.