The condition is cauda equina syndrome. It involves “acute loss of function of the neurologic elements (nerve roots) of the spinal canal below the termination (conus) of the spinal cord,” where the nerves spread out like a horse (equina) tail. Again, this condition causes symptoms in the “saddle” of the body: butt, groin, inner thighs. BACK TO TEXT

I am a science writer, former massage therapist, and I was the assistant editor at ScienceBasedMedicine.org for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.

^{Lie on your back with your knees bent and your feet flat on the floor. Tighten your buttocks and lift your hips off the floor. Tighten your abdominal muscles and lift one foot a couple of inches off the floor. Then put it down and lift the other foot a couple of inches, all while remembering to breathe. “It’s like taking alternate steps,” Pariser says. Work up to doing 30 steps at a time.}
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
_{Paget's disease of the bone is a condition of unknown cause in which the bone formation is out of synchrony with normal bone remodeling. This condition results in abnormally weakened bone and deformity and can cause localized bone pain, though it often causes no symptoms. Paget's disease is more common in people over the age of 50. Heredity (genetic background) and certain unusual virus infections have been suggested as causes. Thickening of involved bony areas of the lumbar spine can cause the radiating lower extremity pain of sciatica.}
The hip flexors are the group of muscles that allow you to lift your knees toward your chest and bend forward from the hips.  What is collectively referred to as the hip flexors is actually a group of muscles that includes the iliopsoas, the thigh muscles (rectus femoris, Sartorius and tensor fasciae latae), and the inner thigh muscles (adductor longus and brevis, pectineus and gracilis).
If you’re worried you’re headed toward a surgeon’s office, there might be hope. According to the Arthritis Foundation, the best way to avoid hip replacement surgery is to get active in an exercise program. In a study, people who participated in an exercise program for 12 weeks were 44 percent less likely to need joint-replacement surgery six years later than those who did not exercise.
_{Lie on your back with your knees bent and your feet flat on the floor. Tighten your buttocks and lift your hips off the floor. Tighten your abdominal muscles and lift one foot a couple of inches off the floor. Then put it down and lift the other foot a couple of inches, all while remembering to breathe. “It’s like taking alternate steps,” Pariser says. Work up to doing 30 steps at a time.}
For those with pain localized to the lower back due to disc degeneration, fair evidence supports spinal fusion as equal to intensive physical therapy and slightly better than low-intensity nonsurgical measures.[15] Fusion may be considered for those with low back pain from acquired displaced vertebra that does not improve with conservative treatment,[14] although only a few of those who have spinal fusion experience good results.[15] There are a number of different surgical procedures to achieve fusion, with no clear evidence of one being better than the others.[83] Adding spinal implant devices during fusion increases the risks but provides no added improvement in pain or function.[11]
_{Spinal fusion is used to strengthen the spine and prevent painful movements in people with degenerative disc disease or spondylolisthesis (following laminectomy). The spinal disc between two or more vertebrae is removed and the adjacent vertebrae are “fused” by bone grafts and/or metal devices secured by screws. The fusion can be performed through the abdomen, a procedure known as an anterior lumbar interbody fusion, or through the back, called posterior fusion. Spinal fusion may result in some loss of flexibility in the spine and requires a long recovery period to allow the bone grafts to grow and fuse the vertebrae together. Spinal fusion has been associated with an acceleration of disc degeneration at adjacent levels of the spine.}

Some of these red flags are much less red than others, especially depending on the circumstances. For instance, “weight loss” is common and often the sign of successful diet! (Well, at least temporarily successful, anyway. 😃) Obviously, if you know of a harmless reason why you have a red flag symptom, it isn’t really a red flag (duh!). But every single actual red flag — in combination with severe low back pain that’s been going on for several weeks — is definitely a good reason to get yourself checked out.