Musculoskeletal Pain

We’ve dealt with Headache, Chest Pain, Abdominal Pain, & Throat Pain — now how about Plain Pain.  Pain anywhere that we know the cause isn’t visceral, like an arm or leg.  Sure, angina radiates to the left arm, but the following discussion aims to distinguish among the many causes of musculoskeletal pain.

There are dozens of special maneuvers, named after their discoverers, to identify specific conditions in one or another joint.  We may touch on a few.  But this posting, far & away the most important, deals with basic principles for distinguishing the different structures in whatever part of the body you’re addressing.  It’s useful for both injuries & also non-traumatic conditions.

What are the structures?  See our handy little table below, with the function & clinical findings for each.  “ROM” = “Range of Motion”.

TABLE  —  THE MUSCULOSKELETAL EXAM

BONE  —  Provides Structure
  • Point Tenderness to Percussion
  • Radiating Tenderness to distant percussion
JOINT  —  Space Between Bones
  • Tender with Passive ROM in any direction
LIGAMENT  —  Attach Bone-to-Bone
  • Tender to Passive ROM that stretches the injury
MUSCLE  —  Power Source to Move Distal Part of Limb
  • Tender to Palpation
  • Tender to Strength-Against-Resistance at site of Muscle
TENDON  —  Connect muscle to distal bone (across a joint)
  • Tender to strength-against-resistance (across joint, at site of tendon)
BURSA  —  Protect muscle and tendon from bony prominences
  • Tender to Palpation
  • Tender to all Active ROM, not Passive ROM
  • May be Painful at Rest
FASCIAL  COMPARTMENTS  —  Separate & Organize Anatomic Structures
  • Rapidly progressive pain & Tenderness of Involved Area
  • Distal Deficits of Sensation, Motor Strength, or Circulation
  • Compartment Syndrome is Limb-Threatening !!!
SKIN  /SUBCUTANEOUS TISSUE  —  Protection & Beauty
  • Tender to Superficial Palpation

This Table, & the following discussion, details what a brilliant physical therapist taught me in Kentucky.  There are no validating studies, and the key points of physical exam are meant as guides, not absolutes.  Equivocal findings are common.  Still, the systematic approach is enormously helpful in determining who may need an x-ray, & clarifying symptoms to both examiner & patient alike.

Let’s say a patient presents with “forearm pain” as a prototypical limb.  What structure might be involved?

BONE —  This is our main rule-out; bone pathology is the worst.  A fracture probably needs casting.  Bone infections & tumors are nasty.  How do we tell if pain comes from bone?

Percussion!  I’ve never had a fracture myself, but can imagine that the last thing I’d want is for someone to pound on it.  However, start gently.  Look First — If you see an obvious gross deformity, don’t percuss!  Get an x-ray.

Say there’s no deformity, and you see dorsal swelling.  If palpation is tender, don’t hit harder.  But maybe it’s just a soft tissue contusion.  So palpate, & then percuss, ventrally, i.e. attack the bone from a different angle to avoid the obvious point of pathology.  If that’s not tender, the bone’s likely OK.

You can also try jarring the elbow, or the wrist, & see if it provokes radiated tenderness at the point of concern.  If so, might be the bone.

Depending on the injury, or location, you may have to invent ways to explore for possible bone involvement.  But ultimately, the bottom line is the same — if you can percuss or even pound on the area in question, without eliciting tenderness, the bone is probably fine.

This principle can be extrapolated to other sites.  Low back pain?  Lightly palpate each lumbar vertebra.  If that’s not tender, palpate more firmly.  Still non-tender?  Percuss gently.  Percuss harder.  Pound!  If that doesn’t hurt, we’re not dealing with a metastasis or spinal abscess.

[Note — When using this principle for acute trauma, be aware of confounders that ruin it.  If the patient is drunk, mentally-altered, or has a larger, painful, distracting injury elsewhere, don’t count on your exam to rule-out Cervical-Spine injury].

JOINT  —  The knee is swollen, maybe even reddish or warm.  How do we clinically determine if this is joint disease (worst case: septic arthritis), or due to a periarticular structure such as tendon, bursa, etc?

Affected joints hurt when they move.  But active range of motion (AROM) utilizes all anatomic structures.  I usually find AROM non-helpful diagnostically.  It’s fine for a ballpark idea of how one copes with ADLs, but except for perhaps bursa, won’t sort out one component from another.

Passive range of motion (PROM) is the key.  Get the patient to fully relax (which may be hard), support the affected area however possible, and gently wiggle the joint to and fro.  Not tender?  Slowly wiggle it further.  If you can carry a joint through full PROM, say from complete flexion to extension, without eliciting tenderness, a primary joint condition is unlikely.

Just be aware that periarticular swelling will often cause uncomfortable external pressure when approaching full flexion.  If the patient begins to flinch at that point — Pause.  Then smoothly move the joint all the way in the other direction to complete extension.  If the latter movement doesn’t elicit tenderness, there’s no joint disease [because you will have been able to fully manipulate the structure without a problem].

LIGAMENT  —  Passive ROM will also elicit tenderness from a sprain, but only in the direction that stretches the ligament.  So if the lateral ankle ligament is partially torn, passive ankle inversion will hurt.  But passive eversion, flexion, and extension won’t.  In joint disease (e.g. gout), all the PROMs, whatever direction, will be tender (because the joint is being manipulated).

Injured ligaments are tender to direct palpation, but not to tapping the joint from the other side.  Try that to any area of an acutely inflamed arthritic joint, and you’ll get a response.

TENDON  —  Motor testing, i.e. strength against resistance, maximizes the pain of a strained or inflamed tendon.  Passive ROM barely bothers it, because the tendon itself isn’t doing anything.  Active ROM may hurt with tendon injury, but will also hurt with ligament, joint, bone, muscle, bursa, & even skin & soft tissue disorders, because all the structures are being manipulated.

By stabilizing the joint, strength against resistance only involves tendon and muscle.  The location of provoked tenderness will distinguish between those structures.

MUSCLE  —  Muscle strains also hurt when testing strength against resistance.  But the tenderness is proximal.  If, say, elbow flexion against resistance hurts in the upper arm over the biceps, that’s muscle.  If the pain is felt down by the antecubital fossa of the elbow, it’s tendon.

BURSA  —  Fluid-filled sacks near bony prominences that protect our soft tissue, bursa get inflamed by repetitive motion or pressure, or perhaps rheumatologic diseases.  They’re found in many places near joints.

Suspect when pain occurs at location of a bursa.  Active ROM in any direction is tender, but Passive ROM should be non-tender.  Superficial bursa may swell.  There’s often focal tenderness to palpation, though some bursa are too deep to access clinically.

FASCIA (COMPARTMENTS)  —  Compartment syndromes are uncommon but potentially devastating.  Pressure accumulates under inflexible fascia, causing permanent tendon and/or neurovascular damage.  This usually happens soon after trauma, commonly fractures but also crush injuries, and very rarely minor trauma or spontaneous bleeding (perhaps among the anticoagulated).  Rapid surgery is essential to preserve function and even limb.

Suspect when focal pain, out of proportion to physical findings, progresses rapidly after trauma.  Distal paresthesias are often the first symptom.  The local compartment swells; distal sensation and then motor strength diminish.  Any hint requires immediate measurement of compartment pressure: Send right to ER [& they’ll send to OR].

SKIN & SUBCUTANEOUS TISSUE  —  Traumatic contusions & hematomas cause pain.  Distinguish this from fractures as described above under BONE.

Imagine a red, hot, anterior knee — is it cellulitis or arthritis [septic arthritis as a worst case]?  Both may hurt with palpation.  Passive ROM will hurt with arthritis, but may also with cellulitis due to skin manipulation.

So improvise.  Manipulate the skin very superficially; if this elicits tenderness, think cellulitis.  Passively flex the knee, causing pain with either condition.  Pause, then gently passively extend the knee a little.  This may relieve the pain from having stretched cellulitic skin, but will hurt equally if there’s joint disease.

To distinguish prepatellar bursitis from cellulitis, try manipulating the skin at the edge of erythema furthest from the bursa [tender with cellulitis].  Palpate different areas within the erythema: all will hurt if it’s cellulitis, but only the point directly over the bursa will with bursitis.  Again, none of these  maneuvers is scientific, validated or exact.  But they’re helpful, especially in terms of underlying principles.

TO  SUMMARIZE  —  A patient presents with musculoskeletal pain, let’s say it’s around a joint.  Inspection may reveal some swelling, but no obvious deformity.  Proceed as follows:

1.  R/O Bone Disease.  Palpate the bones gently.  No tenderness?  Palpate more firmly.  Percuss.  Pound (within reason).  Still no tenderness?  No bone disease (so probably no x-ray).

2.  Passive ROM to address joint disease or ligament injury.  Wiggle the joint (patient must relax).  No problem? — Flex & extend it a little more (both directions).  More.  If PROMs are non-tender (except perhaps at full flexion), there’s no Inflammatory Arthritis.

  • PROM tender in only one direction, suspect a Ligament, especially if also tender to palpation.
  • Osteoarthritis may not cause pain with PROM until a certain point in the range.

3.  Motor Testing (Strength-Against-Resistance)  —   Immobilize the joint & test strength in all the possible directions of joint ROM.  If one movement brings out the patient’s pain, that’s a Tendon strain or Tendonitis.

  • If pain with motor testing is felt over a Muscle, then that’s the source of symptoms.

4.  Active ROM  —  Have patient perform this if you haven’t identified a structure yet.  If several AROMs of a joint hurt, but not PROM, & also not Motor Testing, it’s probably a Bursitis.  Tenderness to palpation over the bursa confirms it.

This posting intended to outline basic principles of musculoskeletal diagnosis.  We didn’t get into the countless eponymous maneuvers for specific areas, like McMurray’s test for meniscal injury (knee), the Apley Scratch for rotator cuff tear (shoulder), Finkelstein’s for DeQuervain’s (wrist) tenosynovitis [2 eponyms here], etc. etc.  Nor did we address less common conditions like fasciitis, reflex sympathetic dystrophy, or other organ systems like neuropathic pain or arteritis.

But hopefully this discussion was helpful.  See also our posting Back Pain.

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