The lumbar plexus forms in the psoas major. Anterior to psoas is the genitofemoral nerve. Lateral to psoas, from cranial to caudal, are iliohypogastric, ilioinguinal, lateral femoral cutaneous, and femoral nerves. Medial to psoas are the obturator nerve and the lumbosacral trunk. The sacral plexus forms in front of the piriformis in the pelvis. Main branches include superior and inferior gluteal nerves in the buttock, sciatic nerve and posterior cutaneous nerve of the thigh, pudendal nerve, and sacral parasympathetics, in addition to local cutaneous and muscular branches.