The adductors are the group of muscles on the inside of the leg responsible for bringing the thigh bones together. There are three main adductor muscles, adductor magnus, adductor longus, and adductor brevis. There are also several other muscles responsible for helping this movement; namely pectineus, and gracilis. These five muscles all originate from the pubis (pubic bone) and ischium (base of the pelvis) and travel down to attach to the back of the thigh bone.
Injury to the adductor muscles is often what someone means when they say they have a groin strain, and this often occurs in sports that require powerful, explosive movements and stretching of the leg out to the side. You can also develop a more overuse kind of adductor injury, where the muscles come together to attach onto the pubic bone.
A slightly less common, but often extremely painful condition around the groin can be pain locally over the symphysis pubis (pubic bone) as a result of local inflammation around the joint. This is most commonly seen in sports involving kicking activities, and also those with rheumatological diseases and sometimes during pregnancy.