Routine exam of a 69-year-old man demonstrates relative weakness of the left EHL muscle (big toe extension is weakened). Ankle jerk and plantar flexion are intact. He appears to have decreased...

Routine exam of a 69-year-old man demonstrates relative weakness of the left EHL muscle (big toe extension is weakened). Ankle jerk and plantar flexion are intact. He appears to have decreased sensation on the dorsum of the left foot and mentions a history of low back pain with occasional “shooting pain” down the side of the left leg. What is the most likely diagnosis?

A. Left L4 radiculopathy

B. Left L5 radiculopathy

C. Left S1 radiculopathy

D. Left S2 radiculopathy

E. Lumbar myelopathy