The correct answer is 1 – a left posterior herniation/protrusion of the lumbar disk.
A right posterior herniation/protrusion of the lumbar disk would likely cause a positive straight leg raise test on the right.
Although piriformis syndrome is capable of causing paresthesia, its symptoms are usually felt deep in the buttock and posterior thigh. The symptoms may also be felt at the posterior aspect of the leg due to irritation of the sciatic nerve and are therefore sometimes misdiagnosed as lumbar spine disc pathology.
Pain can be caused in the sacroiliac joint with the motion of a straight leg raise test the findings do not reproduce the neurological symptoms necessary for a positive straight leg raise test.