Жамбас аймағындағы бұлшық ет: Пириформис бұлшықы және оның қызметтері

Hip muscle in the lateral rotator group

The piriformis muscle is a flat, pyramidally shaped muscle in the gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group. The piriformis muscle has its origin upon the front surface of the sacrum, and inserts onto the greater trochanter of the femur. Depending upon the given position of the leg, it acts either as external (lateral) rotator of the thigh or as abductor of the thigh. It is innervated by the piriformis nerve.

The piriformis is a flat muscle, and is pyramidal in shape. by three fleshy digitations attached to the second, third, and fourth sacral vertebra. It also arises from the superior margin of the greater sciatic notch, the gluteal surface of the ilium (near the posterior inferior iliac spine), the sacroiliac joint capsule, and (sometimes) the sacrotuberous ligament (more specifically, the superior part of the pelvic surface of this ligament). It may be united with the gluteus medius, send fibers to the gluteus minimus, or receive fibers from the superior gemellus. It may have one or two sacral attachments; or it may be inserted into the capsule of the hip joint.

The piriformis muscle is part of the lateral rotators of the hip, along with the quadratus femoris, gemellus inferior, gemellus superior, obturator externus, and obturator internus. The piriformis laterally rotates the femur with hip extension and abducts the femur with hip flexion.

Piriformis syndrome occurs when the piriformis irritates the sciatic nerve, which comes into the gluteal region beneath the muscle, causing pain in the buttocks and referred pain along the sciatic nerve. This referred pain is known as sciatica. Seventeen percent of the population has their sciatic nerve coursing through the piriformis muscle. This subgroup of the population is predisposed to developing sciatica. Sciatica can be described by pain, tingling, or numbness deep in the buttocks and along the sciatic nerve. Sitting down, stretching, climbing stairs, and performing squats usually increases pain. Diagnosing the syndrome is usually based on symptoms and on the physical exam. More testing, including MRIs, X rays, and nerve conduction tests can be administered to exclude other possible diseases. A more invasive, but sometimes necessary treatment involves surgical exploration; however, the side effects of the surgery could be much worse than alternative treatments such as physical therapy. Surgery should always be a last resort.

The piriformis muscle was first named by Adriaan van den Spiegel, a professor from the University of Padua in the 16th century.