What condition is characterized by back pain exacerbated by standing and walking, but relieved with sitting and hip flexion?

The condition characterized by back pain that is exacerbated by standing and walking, but relieved by sitting and hip flexion, is spinal stenosis. Spinal stenosis involves narrowing of the spinal canal, which can compress the spinal cord and nerve roots. This compression can lead to pain, numbness, and weakness, particularly during activities that involve standing or walking. The pain is often relieved by sitting or bending forward, as these positions can help to open up the spinal canal and reduce compression on the neural structures.

In this case, the characteristic relief of pain upon sitting and hip flexion is a classic clinical presentation, often referred to as "neurogenic claudication." Patients may describe their symptoms as similar to the pain experienced in the legs during exercise, which improves with rest or positions that alleviate spinal pressure.

Other conditions such as herniated discs typically cause pain that radiates down the leg and may be aggravated by specific movements or positions rather than the general activity of walking or standing. Muscle strain usually presents with localized pain that does not have the same pattern of relief, and osteoarthritis might involve stiffness and pain that does not present with the clear positional relief noted in spinal stenosis.