A 19-year-old male presents to the clinic with complaints of low back pain ongoing for 2 weeks. He recently had a skateboarding accident where he fractured his right radius. He states that he has run out of the opioid pain medication given to him by the Emergency Department and that he had not noticed the back pain until now. Osteopathic structural examination reveals a positive seated flexion test on the left. His left sacral sulcus is found to be shallower than the right and his left ILA is also found to be shallower than the right. Given the exam findings, which of the following is the most likely diagnosis of the patient’s sacral somatic dysfunction?