Which of the following is a characteristic symptom of spinal stenosis?

The symptom characterized by gradual onset of back and thigh pain exacerbated by walking is emblematic of spinal stenosis because this condition involves the narrowing of the spinal canal, which can compress nerves. When a person with spinal stenosis walks, the increased demand on the lumbar spine and surrounding structures can lead to painful symptoms.

As the individual walks, the spinal canal may become increasingly constricted, resulting in symptoms due to reduced blood flow and aggravation of nerve compression in the lower back and legs. The pain typically eases with rest, as the decreased pressure on the nerves allows for some relief of symptoms. This pattern of pain that is particularly worsened by activity and improved by rest is a classic presentation found in spinal stenosis.

In contrast, the other options present differing symptom profiles that do not align with the gradual and activity-related characteristics typical of spinal stenosis. Hence, the first choice correctly reflects the specific symptomatology associated with this condition.