What nodes are affected when the lower two-thirds of the vagina are involved?

The correct answer pertains to the lymphatic drainage of the lower two-thirds of the vagina, which primarily drains into the inguinal lymph nodes. The lower part of the vagina receives lymphatic drainage from the superficial inguinal nodes due to its embryological origin from the urogenital sinus, which is associated with the development of structures in the lower pelvis and perineum.

In contrast, the upper one-third of the vagina typically drains into the pelvic iliac nodes, as it is derived from the paramesonephric ducts (Müllerian ducts). Therefore, when considering the lower two-thirds of the vagina specifically, the key lymph nodes involved are the inguinal nodes, reflecting the direct anatomical and developmental connections.

The iliac nodes would be pertinent if there were an involvement of the upper part of the vagina, whereas the axillary nodes are not relevant here as they are involved with lymphatic drainage from the upper limb and breast area. Mesenteric nodes deal with the lymphatics of the intestines, which is also unrelated to vaginal drainage. Thus, the inguinal nodes being the site of drainage for the lower two-thirds of the vagina represents the accurate association in this context.