The oblique muscle forms part of the abdominal muscles which are located on the front of the body between the pelvis and the ribs. There are two oblique muscles, namely external and internal. The external oblique muscle is located on either side of the rectum abdominus and it helps to twist the trunk of the body. For example, if you are twisting to the right side, the left external oblique muscle will contract. The internal oblique muscles are located on either side, inside the hip bone and also help the body in twisting.