A 29-year-old Japanese man presented with bilateral weakness in the legs and low back pain. On the day of admission, the patient had gone surfing for the first time in his life and developed sudden low back pain. After 3 h of pain, he noticed weakness in both legs, which gradually worsened. After returning home, he had difficulty walking, and called an ambulance. On physical examination, his manual muscle testing (MMT) score was 3, below the bilateral iliopsoas muscle. Urinary retention was observed, and bulbocavernosus reflex was absent.
