when laying face-up, your foot will rotate out to the side, rather than being in straight alignment 6 Trigger Point Images - Piriformis Causes and Perpetuation of Trigger Points.you may squirm a lot and shift positions trying to get comfortable, and have difficulty crossing one leg over the other knee while seated.entrapment of the pudendal nerve may cause impotence in males and pain with intercourse in females, and pain in the groin or area in front of the anus 5.pain is worse with sitting and activity.in cases of nerve entrapment, the referred pain may extend down all the way to the calf and bottom of the foot, the gluteal muscles may atrophy, the foot may be numb and hard to walk on, and there may be swelling in the leg.referred pain primarily to the sacroiliac region (the joint where the sacrum and big pelvic bone join), over the buttock, and down the back of the thigh.2Įven though the pain referral patterns of the other short lateral hip rotators (the gemelli, quadratus femoris, obturator internus, and obturator externus) have not been distinguished from those of the piriformis, 3 I have had a few cases where pain was not relieved until I worked on the obturator internus (over the obturator foramen), so it is always worth considering that the pain may be at least partially coming from one of the other lateral rotators. 1 Even though some or all of the sciatic nerve's fibers pass through the piriformis in approximately 11% of patients, Dr.'s Travell and Simons speculated that this may actually prevent entrapment problems, since in their research of surgeries, no surgeons had reported this nerve-muscle variation in any of their patients being operated on for sciatic nerve entrapment. Even if there is entrapment, there are also likely trigger points, which may be part of the cause of the entrapment, since trigger points may cause the muscle to bulge. When the piriformis muscle is enlarged, it easily entraps the sciatic nerve and other major nerves and blood vessels. It is commonly called "piriformis syndrome." Females are affected far more than males, with a ratio of 6:1. Trigger points in the piriformis are very common, and are usually involved to some extent anytime there is pain in and coming from the gluteal/pelvic region. Causes and Perpetuation of Trigger Points.