Sciatica Quiz: Ace Your Exams

A 33-year-old woman presents to her primary care physician to evaluate low back pain and left leg weakness. The patient has had worsening low back pain over the past three weeks, with pain radiating into her groin. The patient has also had difficulty maintaining poses due to weakness and pain during her yoga classes.  The patient recently had an upper respiratory infection six weeks ago that resolved. The patient also reports falling on her back several weeks ago while skiing in Colorado. The patient is otherwise healthy and takes oral contraceptive pills daily. Vital signs are within normal limits. Physical examination demonstrates tenderness to palpation over the lumbar vertebrae and reproduction of pain when raising the left leg to 45 degrees. Reflex testing demonstrates 1+ reflexes of the patellar tendon and 2+ reflexes of the Achilles tendon in the left leg. The patient has 4/5 strength with hip flexion and knee extension in the left leg compared to 5/5 strength with these maneuvers in the right leg. Which of the following best describes the underlying etiology of this patient’s clinical presentation?