Where the lower part of the anterior abdominal wall meets the thigh, a crease is formed known as the inguinal groove or crease. The junction is the area of the
medial compartment of the thigh that contains the attachments of the
adductor muscles of the hip, also known as the groin muscles. The adductor muscles that make up the groin consist of the
adductor brevis,
adductor longus,
adductor magnus,
gracilis, and
pectineus. These groin muscles
adduct the thigh (bring the thigh and knee closer to the midline). The groin is innervated by
branches of the lumbar plexus. The pectineus muscle is innervated by the
femoral nerve, and the
hamstring portion of adductor magnus is innervated by the
tibial nerve. In the groin, underneath the skin, there are three to five
deep inguinal lymph nodes that play a role in the
immune system. These can be swollen due to certain diseases, the most common one being a simple infection, and, less likely, from cancer. A chain of
superficial inguinal lymph nodes drain to the deep nodes. There are two depressions called fossae in an area called the
inguinal triangle—the
lateral inguinal fossa and the
medial inguinal fossa. The
inguinal ligament runs from the
pubic tubercle to the
anterior superior iliac spine, and its anatomy is very important for
hernia operations. ==Clinical significance==