I write this chapter so as to make things understandable for non-neurologists. I hope I have not made it too simple. In some sections, I poke fun at us neurologists who, I know, come across at times as arrogant because we tend to speak a different language of our own. I do so in good humor, and hope that I do not offend. I have tremendous respect for my colleagues and the science of neurology.

Here comes our first crucial concept. The nerve fibers literally cover every little part of our body. In general, most electrical messages originate from these fibers. This is where messaging transmission to and from the brain both begins and ends. Two types of little branches exist: ones that go from the body to the brain and ones that go from the brain into the body. The brain analyzes the messages that come to it, and then translates the messages into “feelings” or “sensations” with such names as “soft touch,” “cold,” “hot,” “shakiness,” and—drumroll—a sensation called “pain.”

STEREO PAIN

1. The ball-and-socket hip joint. This joint allows us to move the leg in ALMOST any direction! The muscles that move this joint are better understood if we talk about how they help to do the “Hokey-Pokey”: internal rotation (you put your right foot in), external rotation (you put your right foot out), flexion-extension (you put your bottom in, you put your bottom out), abduction-adduction (then you turn yourself around), and all movements together (then you shake it all about, you do the “Hokey-Pokey,” and that’s what it’s all about!)
   
2. The core skeletal muscles. Think of these in a room with a floor and front, back, and side walls. These include both the large skeletal muscles and the muscles of what gynecologists call the pelvic floor. This room is “built” on top of a foundation called the bony pelvis.
   
3. The “back.” This includes much more than just the spine. It contains the sacroiliac joints, the lumbar and thoracic facet joints (between the spine bones), the discs (the jelly-like stuff in between the vertebrae), and finally the joints between the thoracic spine bones and the ribs (the ones that allows us to breath).
   
4. The pelvic and abdominal organs systems. The gut, kidneys, bladder, connecting tubes, and both male and female reproductive systems.
   
5. And—oh yes—the nerves. Think about the whole tree. Small branches, bigger branches, trunks, and roots go to each of the above structures. Roots come from the thoracic, lumbar, and sacral regions. Let’s just talk about the lumbosacral region. Think of the 5 lumbar vertebrae as having 6 roots on each side, and the sacrum having just 5 on each side. The lumbar region includes the last thoracic (usually T12) vertebra. Each root corresponds in number to the vertebra above it. The lumbar roots send out usually 6 identifiable branches: iliohypogastric, ilioinguinal, genitofemoral branch, lateral femorocutaneous, obturator branch, and femoral. The 6 sacral branches are the sciatic branch, pudendal, coccygeal, inferior gluteal, superior gluteal, and posterior femoral cutaneous.

What About the Pain Characteristics?

Here are the questions you should ask during both the history and physical examinations. Go over them time and again, make them second nature.

1. Where does it hurt? This important question may lead you to a precise diagnosis, but it may also not. Remember what we talked about previously.
   
2. How does it hurt? The quality of the pain helps distinguish between muscle injury and joint injury and the other bafflers. But remember that one injury does not exclude another simultaneous nearby injury, or occasionally even something remote.
   
3. Where does the pain go? If present, pain radiation really helps localize the nerve that is involved.
   
4. How and when did it start? Know the specifics. They often help.
   
5. How bad is the pain? Most clinicians use the visual analogue scale, the 1 to 10 system with 1 representing no pain and 10 the worst pain ever. The answer must come from the patient, not the clinician, and the question must be asked in 3 different ways: while at rest, while exercising, and while performing the movement or activity that specifically aggravates the pain. We usually categorize the answers as “best pain level,” “average pain level,” and “worst pain level.”
   
6. What makes it better? The question is especially useful if position or movement improves the pain.
   
7. What makes it worse? The same thing goes as for the previous question.
   
8. Are there any other symptoms other than pain? Specifically, weakness in any part of the body, tingling, numbness, pins and needles, difficulty urinating, difficulty evacuating, difficulty with sex.

So, How Do We Neurologists Come Up With the Right Diagnoses? How Do We Generally Think?

We guess, of course.

We use our knowledge of neural anatomy to come up with likely diagnoses based on 3 things:

1. The location of pain or other neurological issue
   
2. The likely nerve tissue involved
   
3. The most likely diagnostic culprits

And How Do We Neurologists Generally Classify Characteristics of the Pain With Neural Anatomy?

USING YOUR SAVVY

Here are 3 real case examples of how we super-smart neurologists use our savvy and provide incredible diagnoses. (I still don’t understand why people call us arrogant!)

Case 1. Back Pain in a World Champion Barrel Racer

A 19-year-old woman, a world champion horseback barrel racer, comes with “pain in my lower back.” She points to her lumbar region.

Remember that this region includes consideration of the sacroiliac joints, lumbar and thoracic facet joints, and the discs between the bones in the spine.

Next question: How and when did it start?

The pain began immediately after falling off her horse and landing directly on her rear end. She actually already had some pain there, but this had been mild. The pain worsened with the fall.

Okay, so horseback barrel racing is a very demanding and energetic occupation. The most common cause of pain in any joint is wear and tear. For the joints in the low back, this is also true. Lumbar facet joints are also easily affected by bending over, picking up something heavy with the arms, and twisting. It is virtually guaranteed that she already has some sort of a lumbar facet joint injury.

Next question: How does it hurt?

The pain is deep and aching, almost like if she was “punched” and had a bruise all over her low back.

This is really good! Any joint-related pain from any reason will be deep and aching and feel as though the joint was bruised. Other questions you may ask that might bring out a facet joint problem: Is the pain worse after not moving it for a while? Does it get better when the joint is gently manipulated or worsen if the joint moves too much? Positive answers usually go along with a joint problem—facet, hip, or sacroiliac.

Next question: Any other symptoms with the pain?

She has “numbness” in the same region of the back, but no weakness anywhere nor “pins and needles” or anything else.

Next questions: What makes it better? What makes it worse?

The worst time is when she initially wakes up in the morning. This goes along with a prolonged duration of not moving. Her pain gets better after she gets out of bed and starts to move. This goes along with mild joint pain relief with minimal movement. But when she sits or stands for a while it hurts again. Obviously, positions alter things…again you are thinking joint. She feels good when she begins to ride, but after about 10 minutes, the pain gets much worse. She is using her joint too much.

Perfect. This looks more and more like a joint problem in her lower back.

Next question: Where does the pain go?

One side is no worse than the other. Her pain does not go beyond her buttocks, and on the right side the pain does not reach the buttocks.

This also is very helpful. Usually, pain from either the facet or sacroiliac joints does not go into the legs. It never goes distal to the knee. If it does, you think of other things. In this case, it does not, so your working hypotheses are still operative. Remember also that the disc must be torn to cause localized back pain. If the disc is not torn and instead just bulging or herniated, then the disc-associated symptoms should radiate down the legs.

Next question: How bad is the pain?

Her pain averaged a 5; at best a 2, and at worst a 9.

This is a straightforward documentation of her pretreatment baseline. This will help in assessing the efficacy of diagnostic tests and treatment.

Final question: What has been done so far, and did those things makes things better or worse?

Many other doctors have evaluated her and tried medications that did not work. Anti-inflammatories had equivocal relief, low-dose Elavil (amitriptyline) as an anti-pain medication helped a little bit. An intra-articular hip injection did not help at all. Sacroiliac joint injections also did not help. Actually, she may have had very mild, temporary relief from the latter, but they were not worthwhile even in the short term.

So, we have found there obviously might be an inflammatory component to her pain. The hip injection was done after she provoked her pain by exercise. So, the test was a good one; the pain is unlikely to be coming from her hip. Her partial, but basically insignificant relief from sacroiliac injections probably goes along with chronic wear and tear, and does not mean too much. You are thinking facet joints.

What next? The physical examination, of course.

Physical exam: We did a compulsive bony, muscular, and neurological back examination (of course), in addition to a comprehensive physical examination. She had a normal recent pelvic examination by a gynecologist, and her gynecological history had revealed no suspicious elements. The core muscle and hip specialists in our clinic had already seen her and had been treating her. Our going diagnosis, as we mentioned, was a facet joint problem.

There was only one simple thing left to do to distinguish a lumbar facet joint problem from many other things: a lumbar facet weightbearing test. This test is not foolproof, but in experienced hands, it can lead to the correct diagnosis.

The patient stood up and placed her feet comfortably apart, and then simply twisted her shoulders first to the right and then to the left. We asked the patient to hold her position for 5 seconds, in the end stage of twisting to each side. BOOM!! It was the facet joints! On each side, she could not help but to cry out in pain. None of the other tests reproduced her pain. I was convinced. A recent MRI had showed pronounced thickening of tissue near her facet joints. A new MRI of the lumbar spine revealed unequivocal wear and tear at the last lumbar facet joint on each side.

She then underwent a surgical procedure and is back doing her barrel racing at her previously high level.

Case 2. Groin Pain in an Avid Cyclist

A 56-year-old, well-preserved man comes with: “The darndest pain in my left groin.”

Localization: He pointed to a precise area in his mid-superior thigh, probably deep to his adductors.

The patient used exact anatomical terms, and was just a little bit off in his anatomy. He was close, but not quite accurate. Many patients do that. He was right about the term groin, but wrong about adductors, hip flexors, and sartorius. Watch out. This is a trap. Patients come to you for your answers, not the other way around. Take their anatomical terms with a grain of salt. In his case, he pointed anatomically to a location that easily could have represented 4 structures: the hip, the sacroiliac joint again, the first lumbar nerve root, or the first sacral nerve root. The latter diagnosis is a real diagnosis and new to this differential diagnosis.

Pain characterization: The pain began about 4 to 5 months ago, a day or two after finishing a 40-mile, cross country bicycle race. Initially, the pain was mild; over-the-counter anti-inflammatories made it tolerable. The pain worsened. He had stopped racing because the pain became unbearable after the bicycle competitions.

So, exercise worsens the pain. Exercise has variable effects on nerve root compression pain. The pain is usually maximal at its onset, and in this man’s case, the history does not quite fit. Plus, usually with nerve “pinching,” one gets other symptoms such as pins and needles, weakness, and radiation down a specific route (called a dermatome) according to the nerve root affected. For this to be nerve root compression, he should have something else.

Other symptoms: He had nothing…nada.

Okay, it has to be the joint. We seem to have a solid case for that. The question now, which joint?

A few more questions: He described the pain as constant, deep, and achy, “as if I had a broken bone.” His pain improves minimally while working out or at the beginning of a race, but then grew gradually worse again. He was stiff initially in the morning, then it got “looser.” Sitting was worse than standing.

In general, nerve root problems get worse with position, especially when the leg is straight. The pain also usually improves with bending of the knee. The increased pain with more activity and also with certain positions like sitting goes much more along with joint problems. The sitting pain almost clinches hip vs sacroiliac pain.

It seems obvious now that the pain is coming from a joint. The question is to be as sure as we can as to which joint, always keeping in mind that he could still have a nerve root problem. Nothing in medicine is 100%.

Physical exam: Time for the “Hokey-Pokey” again.

We think in terms of 3 main hip tests. Of course, none of these tests are specific to the hip. Plus, there are many other tests including gait analysis. But I leave those more sophisticated tests to the hip arthroscopy pros.

1. The FABER test: flexion, abduction, and external rotation
   
2. The FADIR test: flexion, adduction, and internal rotation
   
3. The rest of the range of motion

All these tests were abnormal in this man. We confirmed the diagnosis by hip injection (complete relief after it) and MR-arthrography (a big floppy labral tear, severe cam impingement and a loose body, and little arthritis). Hip arthroscopy cured his pain. He is back cycling and winning senior races.

Case 3. Lower Abdominal Pain After Vomiting at a Wedding

A 33-year-old man, a recreational ice hockey player, comes in saying: “My lower abdomen hurts all the time.”

When prompted to localize his pain he points to the entire right lower quadrant of his abdomen.

It began when he started vomiting severely the morning after a wedding. “Food poisoning,” he called it. This was about 6 months ago; since that time, it got much worse.

Okay, think about the mechanism of “injury.” Vomiting increases intra-abdominal pressure and flexion and extension of the chest, abdomen, and pelvic muscles. We begin asking, Is this really a muscle injury or is there something else the Valsava maneuvers could be affecting? Or, are we missing something inside—the gastrointestinal system or something?

The answers to other questions reveal no continued gastrointestinal symptoms. He does describe a vague sense of “numbness” or “tingling” in the skin of that area. He also mentions that his left leg seems a little “weak.” He adds, “And… er…my testicle sometimes burns.”

Yes…we got it, nerves must be involved! That gets us into the electrical tree stuff. Remember, nerve problems happen anywhere within the tree: roots, trunks, branches, or twigs. Our anatomical headlight starts to shine. Like all good neurological athletes, we remember that pinching the fifth lumbar root shoots pain into the lower abdomen and below. The same fifth lumbar root also has branches to the testicles. A portion of the L5 dermatome goes to those areas as well as to the lower leg and foot.

Eureka! We have found it. Or have we? We remember that L1 does some of the same things. Branches of that root contribute to the ilioinguinal, genitofemoral, and lateral femorocutaneous nerve branches. Knowing all you ask more questions.

You ask if the pain travels anywhere else. It turns out the patient has foot pain as well.

Now we are really onto something. Pain that goes beyond the knee is most likely from neurologic compression. Think about the specific pain “map” of the fifth lumbar nerve root: It starts at the belt line, travels to the lateral buttock, then the top side of the thigh, then the knee, then the top of the shin, and finally the top of the foot and big toe. You ask about other symptoms in the map and bet he has them. The patient also noticed that lying down with his legs straight worsened the symptoms, while bending the knee improved it.

The additional questions clinch the diagnosis. Remember, though, that other people do not have all the symptoms on the map. Some may have only groin pain, yet nerve root compression may still be the cause. Yes, it’s tricky. But it is not so tricky if you keep your eyes open and your antennae up.

Interestingly, this patient had an inguinal hernia repair 2 months previously. A surgeon diagnosed this purely on the basis of inguinal pain and that coughing, sneezing, or straining aggravated the pain. Of course, that surgery did not work.

You think you have the diagnosis already and go on to the physical exam.

Physical exam: We examine the sensory maps (dermatomes) for specific nerve roots as well as the motor maps (myotomes). We tease out pain from a possible pinched nerve root (eg, the straight leg raising test) vs maneuvers to test for other causes.

The physical exam sensory map of the fifth lumbar nerve root follows the symptoms map. We usually test pain and light touch. The fifth lumbar root “motor map” gets more precise as it gets into the leg, foot, and big toe. We test for weakness and the inability to do things. For example, we ask the patient to bring his toes to his nose (dorsiflex) while we push down on the foot trying to break the movement. Also, we might passively flex the big toe and ask the patient to extend it. Remember, the patient may be “locked” and can’t move the toe in certain ways and lead you to think there is not weakness. In other words, you can be fooled by these tests if you don’t do them right.

The straight leg raising test is exactly the way it sounds. One simply raises a straight leg (ie, locked in extension at the knee). A positive test occurs only if you evoke pain, numbness, or another neurological deficit and are convinced the deficit travels through the entire sensory map of a particular nerve root.

This patient had a positive straight leg raising test. An MRI of the lumbar spine showed a “pinched” L5 nerve root. Well-directed cortisone injections and physical therapy cured the pain, which has not come back yet. It has been over a year.