Chapter 23: Musculoskeletal System

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Welcome back to the Deep Dive.

We have a massive stack of material today, and frankly, it is one of the most intimidating stacks we've ever covered.

We are taking on the musculoskeletal system.

Oh, absolutely.

Specifically, we are completely breaking down Chapter 23 of Bates' Guide to Physical Examination and History -Taking.

It is a beast of a chapter.

There's really no other way to put it.

You're looking at a system that encompasses over 200 bones, more than 600 muscles, and joints that range from the simple hinges in your fingers to the absolute engineering nightmare that is the knee.

It's an absolute nightmare.

It's dense, it's detailed, and yeah, it's long.

It is dense, and I think that is why so many students, whether they're in nursing, PA school, med school, and even, you know, early clinicians, they just dread it.

It feels like pure memorization of Latin names.

Yeah, vocabulary tests.

Exactly.

But our mission today is to flip that script.

We aren't here to just recite an anatomy textbook verbatim.

We're here to translate those diagrams, the tables, the technical descriptions into a functional audio -based guide you can actually use when a patient walks in limping.

Exactly.

The goal isn't just to name every tuberosity on a bone.

The goal is to figure out why is this person in pain and what can I do about it.

We're going to move from that abstract anatomy to the concrete application.

We need to take what's on the page, which is totally static, and make it dynamic because patients are dynamic.

And to keep us on track, we're going to move strictly through the text in the order it's presented.

So we'll start with the framework, the anatomy and physiology.

Yep, the basics first.

Then we'll move to the detective work of the health history.

After that, the general exam techniques, the IPROM system, and finally, we're going to go head to toe through all the specific regions.

It's a marathon, not a sprint.

Yeah.

But by the end of this, you should be able to look at a shoulder or a knee and not just see skin, but really visualize the machinery underneath.

I love that, visualizing the machinery.

So let's start with that machinery.

Section one, anatomy and physiology, the framework.

Bates starts with the most basic unit, the joint.

But the text makes a point that a joint isn't just where two bones bump into each other.

It's more nuanced than that.

Oh, much more.

An articulation or a joint is a functional unit.

And one of the most critical parts of that unit isn't even the bone.

It's the bursae.

The text highlights these really, really on because they were just so relevant.

These are the disc shaped sacks, right?

Yes.

Roughly disc shaped synovial sacks.

Imagine them as the ball bearings of the body.

They're strategically placed in areas where muscles or tendons have to rub against bone or even against each other.

Okay.

They allow those tissues to glide smoothly over one another.

If you didn't have bursae, simple movements would create friction, heat, and eventually that tendon would fray and snap.

So when we hear bursitis, which is such a

Precisely.

The gliding mechanism fails.

Instead of smooth motion, you get inflammation and pain with every movement.

Now, broadly speaking, Bates categorizes joints into three main types based on how much they move.

And this matters why?

It matters because the type of joint dictates the type of disease you're likely to find there.

So the first and one we deal with most in our clinical exams is the synovial joint.

These are the freely movable ones, shoulders, knees, elbows, that kind of thing.

Correct.

And the engineering here is just fascinating and it's described in box 23 one.

If you're following along the book in a synovial joint, the bones do not actually touch.

Wait, really?

I always picture the skeleton as bones just clacking together like in a cartoon.

If they clack, you have a big problem.

It's usually late stage arthritis in a healthy synovial joint.

The bone ends are covered in this beautiful, slick material called articular cartilage.

Okay.

This is a collagen matrix.

It's tough.

It's slick and it effectively absorbs shock.

And then between those cartilage covered ends is a potential space, the synovial cavity, and it's filled with synovial fluid.

Which acts as the oil in the engine.

It's oil, but it's also food is a really important concept.

That articular cartilage is a vascular.

It has no blood supply of its own.

It relies entirely on that synovial fluid to diffuse nutrients into it and to remove waste products.

So if you dry out that joint, the cartilage literally starves.

It starves and degrades.

And that's a key concept to understand.

Movement circulates that fluid, which then feeds the cartilage.

That's why gentle movement is so important for joint health.

That is a great image.

Now within this synovial family, we have subtypes that determine the geometry of the movement.

Box 23 to 2 details these.

We have the spheroidal joints first.

The classic ball and socket.

Think of the shoulder and the hip.

Structurally, you have a convex ball -like head fitting into a concave cup -like socket.

This shape allows for the widest range of motion in the body.

Flexion, extension, abduction.

Which is moving away from the body.

Right, moving away from the midline.

Adduction, which is moving closer.

Then you have rotation and circumduction, which is that big circular motion.

Then we have the hinge joints.

Much simpler.

Much simpler.

These are flat, planar joints.

Think of your elbow or the interphalangeal joints in your fingers.

They are designed for one thing.

Motion in a single plane.

Open, close, flex, extend.

And they don't like to do much else.

No, they don't like to rotate.

If you force an elbow to rotate, you usually break something or tear a ligament.

They're built for stability in one direction.

And the third type is the condylar joint.

These are kind of the hybrids.

The knee and the TMJ, the temperamentibular joint, are classic examples.

You have articulating surfaces that are convex or concave, and they're termed condyles.

They allow for movement, but they aren't as free as a ball and socket.

They have a primary motion, like a hinge, but usually allow a little bit of rotation or slide to accommodate the mechanics.

Okay, so those are the big movers.

Then Bates moves on to the cartilaginous joints.

Right, these are the slightly movable joints.

The vertebral bodies of the spine are the prime example here.

They aren't held together by a capsule and fluid.

They're separated by these fibrocartilaginous discs.

And inside each disc is the nucleus pulposus.

The jelly donut center.

The famous jelly donut.

Exactly.

It's a shock absorber.

It allows the spine to have some give, some flexibility so you can bend and twist, but it provides enough stability to hold you upright.

And finally, the fibrous joints.

The sutures of the skull.

Here the bones are in direct contact, held together by layers of fibrous tissue.

They are effectively immovable.

Their job is protection, not motion.

So we have the geography down, but there's a concept in Bates that seems to be the golden rule for diagnosis in this chapter.

The distinction between articular and extra -articular structures.

The text emphasizes this so heavily.

Why is this so critical for a clinician?

This is the fork in the road.

It is the absolute first decision you make for every musculoskeletal diagnosis.

When a patient points to a painful area, your first mental task is to figure out, is the problem inside the joint capsule articular or is it outside extra -articular?

Okay, let's unpack the articular side first.

What are we looking for?

What does that mean?

Articular structures include the joint capsule itself, the articular cartilage, the synovium, that's the lining of the joint, and the ligaments that are inside the joint, bathed in fluid.

If you have pathology here, like osteoarthritis, rheumatoid arthritis, or a septic joint, you're going to see deep diffuse pain.

And here is the key takeaway.

It limits both active and passive range of motion.

So active meaning it hurts if I move it myself.

Correct.

And passive meaning it hurts if you move it for me while I'm completely relaxed.

Exactly.

If the joint surfaces themselves are damaged or the capsule is swollen and tight, grinding them together hurts regardless of whose muscles are doing the work.

Structurally, the joint is just physically blocked by swelling or deformity.

You will almost always see swelling with true articular issues.

Okay, compare that to extra -articular.

Extra -articular is everything else wrapping around the joint.

We're talking tendons, bursi, muscles, fascia, skin, and the periodicular ligaments outside the capsule.

If I have, say, tendonitis, that tendon hurts when it's under tension.

So during active motion?

Right.

During active motion, when the patient uses their own muscle to pull on that inflamed tendon, but if I tell the patient to completely relax and I gently move the joint myself, that's passive motion.

I'm not contracting their muscle or pulling that tendon as hard.

So the passive motion is often full and painless or at least much less painful.

That is such a powerful diagnostic filter.

So to recap,

global stiffness and pain in both active and passive range of motion points you towards a joint problem.

An articular problem, yes.

But pain mainly on active motion with passive motion being relatively okay points you towards a soft tissue problem around the joint.

You've got it.

It cuts your differential diagnosis list in half in about 10 seconds flat.

And usually with extra -articular issues, the tenderness is focal.

You can put one finger on the specific tendon or bursa that hurts.

Articular pain just feels like it's coming from deep inside.

Before we leave this framework, Bates throws in a demographic clue.

The age factor.

Under 60 versus over 60.

It's a heuristic.

It's a rule of thumb, but it's a useful one.

If a patient is under 60, you're generally thinking about things like repetitive strain injuries,

overuse syndromes, maybe crystal -induced issues like gout.

You also see the onset of inflammatory diseases like rheumatoid arthritis or psoriatic arthritis in this age group.

And over 60, the machinery starts to wear out.

You're looking at osteoarthritis, osteoporotic fractures, or things like polymyalgia rheumatica.

Obviously, it's not an absolute rule a 20 -year -old can get a septic joint, but if a 70 -year -old comes in with new hip pain, you aren't thinking repetitive strain as your first guess.

You're thinking joint failure or fracture.

All right.

Framework established.

That makes a lot of sense.

Let's move to section two.

Health history, the detective work.

The text lists the big three symptoms that bring people into the clinic.

Joint pain, neck pain, and low back pain.

That is the bread and butter of musculoskeletal complaints.

It accounts for millions upon millions of visits every year.

So a patient comes in with pain.

We need to drill down.

Bates uses the seven attributes of a symptom.

We've seen this in other systems, but how does it apply specifically to joints?

Location is number one.

It's the most important.

And there's a specific technique Bates recommends.

Ask the patient to point to the pain with one finger.

Why the single finger?

That seems oddly specific.

Because patients are often vague.

They'll rub their whole shoulder with their palm and just say, it hurts.

That could be the joint, the trapezius muscle, the neck, or can even be referred pain from the gallbladder or the heart.

But if they can pin it to the AC joint with one finger or right on the occipital groove,

you have saved yourself 20 minutes of guessing.

You've localized the anatomy.

Then we count the joints.

Yes.

Is it monoarticular, meaning just one joint?

Is it oligoarticular, which is two to four joints?

Or is it polyarticular, four or more?

This simple count immediately tells you if you're dealing with a local injury or a systemic disease.

Trauma is usually monoarticular.

Rheumatoid arthritis is almost always polyarticular.

That leads us right to pattern.

This is where we really start to differentiate the types of arthritis, right?

Exactly.

You ask questions to find the pattern.

Is the pain symmetric?

RA acts like a mirror image.

It hits both wrists, both knees.

Psoriatic arthritis, on the other hand, is often very asymmetric.

Then you ask, is it migratory?

Does it seem to jump from the left knee to the right elbow, like we see in rheumatic fever?

Or is it additive, you know, starting in the knee and then spreading to the hip and then the hand?

Then we have the quality and severity, and specifically looking at the timing of stiffness.

This brings up the inflammatory versus mechanical debate.

This is just crucial for the history.

Inflammatory pain, like you see in RA or an infection,

is characterized by something called the gel phenomenon.

The joint gels up when it sits still.

So these patients have terrible morning stiffness.

Terrible.

It can last for an hour or more.

But it gets better with activity as the inflammatory fluid warms up and circulates.

Which is the complete opposite of mechanical pain.

Right.

Mechanical pain, like you see in osteoarthritis, is a wear and tear issue.

It hurts when you use it.

It feels better when you rest.

The morning stiffness is brief, maybe 15 or 30 minutes, just until they loosen up.

But if they walk all day, it hurts more at night.

And we can't ignore the associated manifestations.

The text calls these constitutional symptoms.

You can never, ever look at a joint in isolation.

If a patient comes in with a swollen knee, you have to ask, Do you have a fever?

Chills.

Have you lost weight without trying?

Do you have a rash?

And why is that so important?

Because if you miss the fever, you might miss a sepid knee, which is an infection in the joint that can destroy the cartilage in days.

Or if you miss the classic butterfly rash on the face, you might miss systemic lupus erythematosus.

The joint is often just the signal flare for a system -wide fire.

Bates zooms in specifically on neck and back pain in the history section.

There's a real safety check here regarding nerve involvement.

With the neck and back, you're always, always trying to rule out nerve compression.

You have to ask about radicular pain.

That's pain that radiates down an arm or a leg in a specific nerve pattern.

So sciatica is a type of radicular pain.

Exactly.

You ask about numbness, tingling, weakness.

If the pain shoots down the leg past the knee, that's highly specific for a disc herniation that's compressing a nerve root.

And the red flags.

The text mentions cauda equina syndrome.

This sounds like something we absolutely cannot afford to miss.

You cannot miss it.

Ever.

The cauda equina is Latin for horse's tail.

It's that bundle of nerve roots at the very base of the spinal cord.

If that gets compressed, usually by a massive disc herniation or a tumor, it's a surgical emergency.

What are the questions you have to ask?

You have to ask about bladder or bowel retention or incontinence.

You ask about saddle anesthesia, numbness in the groin, inner thighs and the perineum, the area you'd sit on a saddle.

If they have those symptoms, they need an MRI and a surgeon immediately.

If you wait, they could have permanent paralysis or loss of bladder control.

Okay, that is a heavy but very necessary warning.

So we have our history, we have our clues.

Now we stand up.

Section three, the physical examination, the general approach.

Bates gives us a fantastic mnemonic.

Eye prompts.

Eye prompts.

It stands for inspection, palpation, range of motion and special maneuvers.

It is the roadmap.

If you ever get lost in an exam, if you don't know what to do next, just go back to eye prompts.

It works for the finger and it works for the hip.

Step one, inspection.

Look before you touch and look at the surrounding tissues, not just the joint.

You're looking for symmetry.

Is one shoulder higher than the other?

Is one knee obviously more swollen?

Is there muscle atrophy?

Atrophy is a big one.

Atrophy is a huge clue for chronic issues because muscles waste away very quickly when pain prevents you from using them.

Also look for skin changes.

Any ridness, bruising or old surgical scars.

Step two, palpation.

Now you touch, but you touch with purpose.

You are feeling for the bony landmarks to orient yourself.

We call this surface anatomy.

You're feeling for tenderness and you're feeling for temperature.

And Bates has a specific tip for checking temperature, doesn't he?

Yes, use the backs of your fingers.

The skin on the back of your hand is thinner and much more sensitive to subtle temperature changes than the calloused pads of your fingertips.

You're hunting for the warmth of inflammation.

And we're also feeling for bogginess.

What a great word.

It's the perfect word for the texture of synovitis.

A healthy joint line feels firm.

You feel bone in tight capsule and inflamed synovium feels doughy or boggy.

And if there's fluid in there in a fusion, it feels fluctuate like a water balloon.

Step three, range of motion.

We've discussed active versus passive already.

And finally, S for special maneuvers.

These are the stress tests.

This is where we twist, we pull, and we push to test the tensile strength of specific ligaments and tendons.

We'll get into the specific ones in each of the regions.

One term that comes up in the general exam is crepitus.

Crepitus.

It sounds like gravel grinding.

It's an audible or palpable crunching when the joint moves.

It means that the smooth articular cartilage has roughened up or worn away completely.

It's the hallmark sound of osteoarthritis.

It is the sound of friction.

Okay.

We are prepped.

We have our eye problems tool belt.

Now we go region by region.

Section four, the TMJ and shoulder.

Let's start with the jaw.

The TMJ is the most active joint of the body.

We use it to talk, to eat, to yawn.

Inspection is simple.

You just look for symmetry.

Palpation involves placing your fingertips just in front of the tragus of the ear and asking the patient to open and close their mouth.

What are we feeling for there?

You're feeling for smooth motion.

You might feel a click or a pop.

A click is actually very common and often benign, but it can indicate a disc displacement within the joint.

We also check range of motion.

Can they fit three of their own fingers in their mouth?

That's a normal opening.

What else for a rung?

Can they protrude the jaw, jet it forward?

Can they move it side to side, laterally?

The text mentions a risk of dislocation here.

Yes.

Extreme mouth opening, like a huge yawn, can actually cause the condyle to slide too far forward and get stuck in front of the articular eminence.

It's rare, but it definitely happens.

Moving down to the shoulder.

This feels like the most complex joint to examine.

It is.

It absolutely is.

Because the shoulder sacrifices stability for mobility.

It's barely a ball and socket.

It's more like a golf ball on a tee.

The socket, the glenoid, is very shallow.

So it relies on other things to hold it in place.

It relies heavily on dynamic stabilizers, the rotator cuff muscles, which you can remember with the pneumatic succeeds,

supraspinatus, infraspinatus, teres minor and subscapularis, to keep that ball on the tee.

Inspection involves looking at the scapula too, right?

The shoulder blade.

Yes.

You absolutely have to check for scapular winging.

Have the patient stand and push against a wall with both outstretched arms.

If the medial border of the shoulder blade pops out like a chicken wing, that tells you the serratus anterior muscle is weak, or the long thoracic nerve that supplies it is injured.

Palpation is a real geography lesson here.

You have to walk your fingers across all the landmarks.

You do.

You have to be systematic.

Start at the sternum.

Walk your fingers out along the clavicle until you feel the AC joint.

That's the bony bump on top of the shoulder.

Then find the coracoid process, that little nub under the clavicle.

It feels deep.

Then the greater tubercle on the humerus.

If you don't know where your fingers are, you don't know what structure is actually hurting.

Let's talk about range of motion.

The shoulder does everything.

But Box 23 -8 mentions something called scapulothoracic motion.

What is that?

That's a crucial concept.

When you raise your arm out to the side, the first 90 degrees or so is mostly the arm moving in the socket, the glenohumeral joint.

But to go all the way up to the ceiling, the scapula actually has to rotate on the ribcage.

Oh, interesting.

Yeah, for every three degrees of total arm elevation, about two come from the main joint, and one comes from the scapula moving.

So if the scapula is stuck, you physically cannot raise your arm all the way.

Let's get into the special maneuvers for the shoulder.

Bates calls these the high -yield tests.

Let's start with the crossover test.

This test isolates the acromial clavicular, or AC joint.

You take the patient's arm and you cross it horizontally over their chest, like they're trying to reach for their opposite shoulder.

This compresses the AC joint.

If they have pain right on top of the shoulder, that's a positive test for AC joint arthritis or injury.

Then we have the test for tears, the job arm test.

This is a classic test for the supraspinatus tendon, which is the most commonly torn rotator cuff tendon.

You passively lift the patient's arm straight out to the side, abduct it to 90 degrees, then you let go and ask them to lower it slowly.

And what happens if it's torn?

If the tendon is torn, they can't control that eccentric load.

The arm will drop smoothly until a certain point, and then boom, it just dropped to their side.

Or they'll hitch their whole shoulder up, try to compensate.

And the empty can test.

Also for the supraspinatus, you have the patient hold their arms out in front of them, about 45 degrees to the side, and then turn their thumbs down, like they're emptying a can of soda onto the floor.

Then you apply downward pressure on their arms while they resist.

Pain, or importantly weakness, suggests a tear or impingement of that muscle.

Okay, moving down the arm, section five.

Elbow, wrist, and hand.

The elbow is much easier, it's a simple hinge.

Inspection focuses on the triangle formed by the alacranon process, that's the tip of the elbow, and the two epicondyles on the sides.

When the arm is bent to 90 degrees, they form a perfect isosceles triangle.

And palpation here is famous for diagnosing the sports elbows.

Exactly, you palpate the epicondyles, the lateral epicondyles on the outside of the elbow.

If that specific spot is tender, it's lateral epicondylitis or tennis elbow.

It affects the wrist extensor muscles.

And the other side.

The medial epicondyle is on the inside.

Tenderness there is medial epicondylitis or golfer's elbow, and that affects the wrist flexor muscles.

Moving to the wrist and hand.

Bates notes that these are incredibly vulnerable because there's almost no padding, it's just skin, tendon, and bone.

Which is why inspection is so incredibly high yield.

In osteoarthritis, we look for bony overgrowth.

Hebrided nodes are these hard bony nodules at the DIP joints, the knuckles right by the fingernail.

Bouchard nodes are at the PIP joints, the middle knuckles.

Seeing these nodes is almost diagnostic for OA.

And in rheumatoid arthritis, how does that look different?

RA looks very different.

You see ulnar deviation, the fingers drift sideways toward the pinky, and you see swelling.

The boggy swelling at the MCP joints, the big knuckles where the fingers join the hand.

If you squeeze those MCP joints together and it feels squishy and is very painful for the patient, that's active RA senovisis.

There is a specific spot called the anatomical snuff box.

I've always loved that name.

It's a classic bit of anatomy.

If you extend your thumb backwards, away from your fingers is that little hollow that forms at the base of the thumb on the wrist.

Okay, I see it.

If a patient falls on an outstretched hand and has tenderness precisely in that snuff box, you have to treat it as a scaphoid fracture, even if the X -ray is negative.

The blood supply to that little bone is terrible, and if you miss the fracture, the bone can die.

What we call a vascular necrosis.

Well, let's hit the hand maneuvers, the Finkelstein test.

This is for D.

quirvain's tenosynovitis, which is inflammation of the thumb tendons on the side of the wrist.

You have the patient tuck their thumb into their palm and make a fist over it.

Then you gently deviate the wrist toward the ulnar side, so down towards the pinky.

And a positive test is?

If they wince or scream in pain, it's positive.

It's very common in new parents from lifting babies because of the wrist angle.

And the carpal tunnel tests,

tunnel and phalan.

Tinal sign is elicited by tapping lightly over the median nerve at the wrist.

A positive test is a zeoling or an electric shock feeling that shoots into the fingers, specifically the thumb, index, and middle finger.

And phalan.

Phalan's test involves having the patient press the backs of their hands together with their wrists flexed at 90 degrees for 60 seconds.

This position compresses the carpal tunnel.

Numbness or tingling in that same median nerve distribution suggests compression.

But, and Bates is really clear on this, these tests have limited sensitivity and specificity.

A negative test doesn't rule it out completely, but a positive one really helps build your case.

Moving to the central pillar, section six, the spine.

For the spine, the first thing is posture.

We look at the curves.

The neck or cervical spine and the low back, the lumbar spine should curve inward.

That's a lordosis.

The mid back or thoracic spine curves outward.

That's kyphosis.

It should look like a general S from the side.

An inspection from behind involves checking for alignment.

Exactly.

Is the head midline or the shoulders level?

Is the pelvis level?

If one shoulder's higher than the other, you might be looking at scoliosis.

And palpation.

We're feeling the spinous processes, those dinosaur bumps down the back.

What is a step off?

You want those bumps to be in a smooth vertical line.

If you run your finger down the lumbar spine and suddenly your finger steps in or steps out significantly, that can indicate one vertebra has slipped forward over another.

That's a condition called spondylolisthesis.

It's a structural instability that often causes a lot of pain.

We also check the SI, the sacroiliac joint.

Yes, you look for the dimples above the buttocks.

Those are the posterior superior iliac spines or PSIS.

You press right there.

Tenderness suggests sacroilias, which is a common finding in conditions like ankle losing spondylitis.

There's a percussion element here too, but it's related to the kidneys.

Right, the costo -vertebral angle or CVA, tenderness.

You place your hand flat on the back over the kidney area, which is the bottom of the ribs, and then you thump the back of your hand with your other fist.

If that causes a sharp, jarring pain, it's not the back muscles.

It's very likely a kidney infection or pylonephritis.

Range of motion includes flexion touching the toes.

Bates mentions checking for scoliosis specifically here.

Yes, this is the Adams -Forward Bend Test.

When the patient bends forward to touch their toes, you get down at their level and look along the horizon of their back from behind.

If one side of the rib cage is higher than the other, what we call a rib hump, that means the spine is rotated.

That is the hallmark of structural scoliosis.

Let's move to the lower body, section seven, the hip.

The hip is tricky because it's so deep.

It's buried under these thick gluteal muscles.

You can't really palpate the joint directly like you can a knee.

So Bates emphasizes gait analysis.

The walk tells the story.

And we have two phases of gait, stance and swing.

Correct.

Stance is when the foot is on the ground bearing weight, which is about 60 % of the cycle.

Swing is when the leg is moving forward, the other 40%.

When we look at the width of the base, it should be about two to four inches from heel to heel.

And you're looking for the Trendelenberg sign.

What is that?

It's a test of the gluteus medius abductor muscles.

These are the muscles on the side of your hip.

When you stand on your right leg, your left hip should actually rise a little bit because your right gluteal muscles are contracting to hold the pelvis level.

Okay.

If the left hip drops when they stand on the right leg, it means the right abductor muscles are weak.

The patient will often lurch their body to that side to compensate.

That's a positive Trendelenberg gait.

And palpation relies on external landmarks like the trochanteric bursa.

Yes.

If you press on the big bony prominence on the side of the hip, that's the greater trochanter of the femur.

It's exquisitely tender.

That is cochanteric bursitis.

It's an incredibly common cause of hip pain that isn't actually the hip joint itself.

Now, range of motion.

Flexion is bringing the knee to the chest.

But Bates notes a trick here regarding the hamstrings.

Right.

If you try to lift a straight leg up, tight hamstrings will stop you early.

And it won't tell you about the hip joint itself.

If you bend a knee, you relax the hamstrings.

And then you can see how much the hip joint itself can actually flex.

Box 2316 shows this beautifully.

Rotation always confuses students.

To test internal rotation of the hip, you swing the foot out.

That feels backward.

It does.

But you have to think about the mechanics.

Visualize the thigh bone, the femur, as a lever.

And the knee as the pivot point.

If the patient is lying on their back with the knee bent at 90 degrees and I push their foot laterally or out, the head of the femur has to twist medially or in inside the socket.

So foot out is internal rotation.

And foot in is external rotation.

You got it.

Special maneuvers.

The Faber test.

F -A -B -E -R.

It's a mnemonic for the motions.

Flexion, abduction, and external rotation.

You have the patient make a figure four with their legs.

You place the ankle on the ultimate knee.

Then you gently press down on the bent knee toward the table.

And what does pain there mean?

If that hurts deep in the groin or the buttock, it suggests hip intraarticular pathology or could also point to SI joint issues.

And the Kendall test for contractures.

Yes, for this one you have the patient lie flat.

You ask them to pull one knee tight to their chest.

The goal of this is to flatten their lumbar spine against the table so they can't cheat.

If the other leg, the one that's supposed to be straight, involuntarily lifts off the table, it means the hip flexor, the iliopsoas muscle, on that side is too tight to allow the leg to lie flat.

That's a flexion deformity or contracture.

Section eight, the knee.

This is a massive section in the book.

The knee seems designed to fail.

It really is.

It's a high stress hinge that relies entirely on ligaments for its stability.

You have the shock absorbers, the medial and lateral menisci.

You have the side stabilizers, the collateral ligaments, the MCL and LCL.

And you have the internal cross braces, the cruciate ligaments, the ACL and PCL.

Inspection starts with the hollows around the patella, the kneecap.

Right.

A healthy knee has these defined hollows on either side of the kneecap.

If those are gone, if it looks puffy, you have fluid in the joint and a fusion.

And Beats gives us two specific tests for this.

The bulge sign.

This is for small amounts of fluid.

You stroke the medial side of the knee upwards to displace any fluid into the suprapatellar pouch above the kneecap.

Then you tap or stroke the lateral side downwards.

You watch the medial side for a bulge or a ripple of fluid returning.

It's a subtle sign.

And for a lot of fluid,

the balloon sign.

Also called balloting the patella.

For this, you compress the pouch above the kneecap with one hand to force any fluid down.

And then you push the patella down against the femur with your other thumb.

If it feels like it's floating or bounces back up like a bobber in water, that's a major effusion.

Now the stress tests.

These are the ones every sports fan knows.

Let's start with the MCL and LCL.

These tests involve applying leverage to the joint.

To test the MCL, the medial collateral ligament, you apply a vulgar stress.

You hold the ankle with one hand and push the knee inward from the outside.

You're trying to gap open the medial side.

And a torn ligament would feel loose.

Exactly.

You'd feel it open up like a book.

Or there would be no hard end point to the motion.

For the LCL, you do the opposite.

A varus stress where you push the knee outward from the inside.

Then the ACO.

The anterior cruciate ligament.

The classic test is the anterior drawer.

You have the patient bend their knee to 90 degrees.

You sit on their foot to stabilize it.

And then you pull the tibia forward like you're opening a drawer.

But Bates is very clear that the Lachman test is actually better and more sensitive.

How is a Lachman test different?

You only bend the knee about 15 or 20 degrees.

This position relaxes the thigh muscles that might be guarding and fighting you.

You stabilize the femur with one hand and give a quick jerk to the tibia forward with the other.

You're feeling for a firm stop.

A mushy end point or excessive forward movement means the ACL is gone.

And the PCO.

The posterior cruciate ligament.

For that, you do the posterior drawer.

Same position as the anterior, knee at 90 degrees, but you push the tibia backward.

If it sags back and creates a step, that's a PCL tear.

Finally, the menisci.

The McMurray test.

This one feels like a wrestling move.

It is a bit technical.

You have to fully flex the patient's knee.

You cup their heel and you place your other hand on the joint line so you can feel what's happening.

To test the medial meniscus, you externally rotate the foot and then slowly extend the leg while applying a valgus stress.

So you're trying to grind the meniscus between the bones.

You are.

You're trying to trap the torn piece of meniscus.

If you feel a clunk or a painful click right at the joint line as you extend, that's a positive McMurray test.

It strongly suggests a meniscal tear.

Section 9.

Ankle and foot.

We are nearing the ground.

The main ankle joint, the tibiotalor joint,

allows for dorsiflexion, which is pulling your toes up, and plantar flexion.

Pointing your toes down.

Then the subtelar joint below it allows the foot to rock side to side inversion and eversion.

Inspection looks for things like hallux valgus.

Right, which is commonly known as a bunion.

That's where the big toe points in toward the other toes, and the head of the first metatarsal bone sticks out medially.

It can be very painful and make wearing shoes very difficult.

And the big maneuver here is the Thompson test.

This is for the Achilles tendon.

This is just a brilliant and simple test of mechanics.

You have the patient either kneel on a chair or lie face down with their feet hanging off the edge of the table.

You then squeeze their calf muscle firmly.

Okay.

If the Achilles tendon is intact, the foot must point down.

It must plantar flex because you are mechanically shortening the muscle tendon unit.

And if it doesn't move at all.

If you squeeze that calf and the foot stays dead still, the connection is broken.

The Achilles tendon is ruptured.

It is diagnostic.

There's no faking it.

We have covered the entire body, but we aren't done.

Section 10, documentation and health promotion.

This is where the exam becomes a permanent medical record.

And precision is everything.

Don't just right knee hurts,

right?

Right knee, positive Lackman test, negative McMurray, moderate effusion noted with positive balloon sign.

Describe the specific maneuver that caused pain.

That tells the next doctor who reads your note exactly what anatomy is involved.

And finally, health promotion.

We need to prevent these things from happening in the first place.

Weight control is absolutely massive.

Bates notes that even modest weight loss significantly reduces the lifetime risk of developing knee osteoarthritis.

Every single pound of body weight you carry places four pounds of stress across your knees when you walk.

Wow, four pounds.

Four pounds.

So losing 10 pounds feels like 40 pounds to your knees.

And for low back pain.

We have to look beyond the physical and look at the yellow flags.

These are the psychosocial factors.

Things like anxiety, depression, and job dissatisfaction are actually very strong predictors of acute back pain becoming chronic.

You have to treat the whole person, not just their spine.

And osteoporosis screening.

It's the silent disease until a bone breaks.

Yeah.

We need to be screening women over the age of 65 or younger women with significant risk factors with DEXA scans to measure their bone mineral density.

And linked directly to that is fall prevention.

Right.

A hip fracture in an elderly patient has a very high mortality rate.

So checking for trip hazards like rugs, improving lighting, and reviewing medication lists to prevent falls is just as important as prescribing calcium supplements.

So what's the big takeaway here?

We've gone from synovial fluid all the way to McMurray tests.

The takeaway is that the musculoskeletal exam is logical.

It's not magic.

It's applied anatomy.

If you know where the structure is and you know what that structure does, you can figure out how to test it.

The maneuvers, the how -to are just ways to isolate the why of the patient's pain.

And getting comfortable with touching the patient, moving their limbs, and trusting what your hands are feeling.

Exactly.

Don't just rely on the MRI.

Your hands can often tell you the answer before the patient even gets to the scanner.

That is the perfect place to wrap this up.

We really hope this deep dive helps you visualize the anatomy,

perform the IPROMs with confidence, and ultimately help your patients move better.

From the last Schmidt Lecture team, thank you for listening.

Now go practice those maneuvers.

See you on the next deep dive.