Piriformis Muscle, Posterior View

Description

Centered on the posterior pelvis and proximal femora, the piriformis muscles are emphasized bilaterally as they arise from the anterior (pelvic) surface of the sacrum and course laterally through the greater sciatic foramen toward the superior aspect of the greater trochanter. Superiorly, the lower lumbar vertebrae and lumbosacral junction provide bony context, while laterally the iliac crests frame the pelvic inlet and, inferiorly, the femoral heads and necks sit deep to the acetabula at the hip joints. Each piriformis runs nearly horizontal in this posterior view, spanning from the midline sacrum to a lateral femoral insertion. Short and direct. Piriformis anatomy matters because it is the most common landmark used to organize the deep gluteal region, with the sciatic nerve typically emerging inferior to it as it exits the pelvis, and variants in that relationship underpin discussions of deep gluteal pain syndromes and nerve entrapment patterns. Clinicians also use its line of pull to explain why hip flexion changes piriformis function, from a primary lateral rotator in extension to a potential abductor in flexion, a point that helps reconcile conflicting exam findings in posterior hip pain. Surgeons and interventionalists reference this corridor when planning posterior hip approaches and image guided injections, where the greater sciatic notch and greater trochanter act as palpable and radiographic landmarks. Ideal for gross anatomy teaching on the pelvis and hip, and for orthopaedic, sports medicine, and physical therapy materials covering external rotators, gait mechanics, and the differential for sciatica versus local entrapment near the greater sciatic foramen. Anatomical accuracy verified by SciePro's Medical Advisory Board.