Which nerve is responsible for sensory and motor innervation of the lower vagina, perineum, and vulva?

The pudendal nerve is the primary nerve responsible for both sensory and motor innervation of the lower vagina, perineum, and vulva. It emerges from the sacral plexus and provides a critical role in the function of the pelvic region.

Sensory fibers from the pudendal nerve supply sensation to the skin of the vulva and the perineum, allowing for the perception of touch, pain, and temperature in these areas. Additionally, its motor fibers innervate the muscles of the perineum, including those involved in the support and function of the pelvic floor, which is essential for processes such as urination and parturition.

In contrast, the other nerves listed do not serve these functions in the same way. The femoral nerve primarily innervates muscles of the anterior thigh and provides sensation to the anterior thigh and part of the medial leg. The sciatic nerve is mainly responsible for innervating the posterior aspect of the leg and foot, while the obturator nerve supplies the medial thigh but does not affect the perineal or vulvar regions. Thus, the pudendal nerve is the key player for the areas mentioned in the question.