Reminder
We do not examine randomly.
We examine to test a hypothesis.
History first
History does not just collect information; it generates a ranked set
of hypotheses. A patient with sudden breathlessness and pleuritic
chest pain after a long flight has already given you a shortlist.
The physical examination tests it.
Targeted examination
The system you examine most carefully follows from the most likely
diagnosis your history points to. For that patient, you look for a
swollen calf, tachycardia and signs of right heart strain, not only
for crackles.
The standard
Before you examine a system, know what finding you are looking for
and what it would mean. A clinician who cannot explain why they
examined a system is performing a ritual rather than applying
clinical reasoning.
What the Examination Is For
The physical examination is not a search party; it
is primarily a verification exercise, though
unexpected findings will sometimes redirect the hypothesis entirely.
The Purpose
Why we do physical examination
Purpose 1
Support the most likely diagnosis: find the
expected signs.
Purpose 2
Exclude serious alternatives: look for signs
that would change management urgently.
Purpose 3
Assess severity and complications: findings
that determine how sick this patient is right now.
Note on language: History generates a ranked list of
hypotheses. The examination is how you begin to confirm or discard
them.
The Method
What history generates,
and what examination does with it
01
History generates
Hypotheses & priorities
The history gives you a working differential, ranked by
probability. The leading hypothesis determines where you begin.
Ranked differential diagnoses
Organ system of primary interest
Dangerous diagnoses to actively exclude
02
Examination is
Targeted verification
You examine the system the history points to, thoroughly and
systematically. Other systems only if the differential demands it.
Primary system: examined in full
Other systems: only if justified
Look for: signs, severity, complications
03
Findings either
Confirm or redirect
Examination findings will either reinforce your working hypothesis,
or open a new diagnostic branch you did not anticipate.
Expected signs present → proceed.
Expected signs absent → consider: was the examination adequate?
Has treatment already modified findings? Then reconsider the
hypothesis.
Unexpected signs → new hypothesis.
Organ System
Finding the system of primary interest
History directing examination
Common Things are Common: most common system first
Presenting complaint → Primary system → Targeted examination
| Presenting Complaint |
Primary System |
Cross-system Alert |
| Chest pain on exertion |
Cardiovascular |
Respiratory (exercise-induced bronchoconstriction or pulmonary
embolism in appropriate clinical context)
CVS is more likely, but exertional dyspnea may point to
both.
|
| Chronic cough with purulent sputum |
Respiratory |
Cardiovascular (cardiac cough: nocturnal, non-productive)
If cough is nocturnal and non-productive, consider heart
failure.
|
| Epigastric burning pain |
Gastrointestinal |
Cardiovascular (inferior MI can present as epigastric pain)
A classic trap: the symptom does not always match the
system.
|
The table is a starting point, not a rule. History
may point to multiple systems simultaneously. If the history is
ambiguous, begin with the most dangerous system first, not the most
common.
What to Look For
Positively and negatively relevant findings
＋
Positively Relevant Findings
Signs whose presence increases the probability of a diagnosis. You
examine specifically to find them, and their absence constitutes
a pertinent negative only if they were expected.
- Signs characteristic of the leading diagnosis
- Severity markers: how unwell is this patient?
- Complications of the suspected condition
- Signs confirming the organ system is involved
−
Negatively Relevant Findings
Findings whose absence is diagnostically meaningful.
Depending on the finding, its absence can lower the
probability of the diagnosis under consideration (when it's a
feature you'd expect to see) or raise it (when the
finding is more typical of a competing diagnosis). Equally
important either way, and equally deliberate. You look for them
specifically so you can say they are not there.
-
Absent edema in suspected heart failure - Lowers probability
-
No lymphadenopathy in suspected lymphoma - Lowers probability
-
No relief of chest pain with antacids in suspected cardiac cause
(vs. GERD) - Raises probability
-
No history of trauma in a suspected pathological fracture -
Raises probability
Key insight
The absence of an expected finding is not the same as finding nothing.
A pertinent negative is a deliberate, documented
observation, not an omission. Saying "no peripheral edema" tells a different
clinical story from simply not examining the legs.
The Checklist
Six questions before you examine
Bedside & Oral Exam Checklist
Before you lay a hand on the patient: ask these
Apply to every patient encounter where clinical reasoning is required.
With experience, these steps become rapid and implicit, but they
remain the underlying structure.
1
What is/are the presenting complaint(s)?
The complaint, not the diagnosis.
"Breathlessness for 4 weeks", not "I think
it's heart failure."
2
Which organ system is primarily involved?
Based on the history, not assumption.
This determines where you begin. If unclear,
begin with the most dangerous system.
3
What are my top three differential diagnoses?
Ranked by probability: guided by 'Common Things are Common,'
but with dangerous diagnoses named explicitly regardless of
their probability ranking.
Name them before you examine. This is how you
know what to look for.
4
What findings should I look for to support each?
The positively relevant findings: signs that,
if present, would substantially increase the probability of a
diagnosis. List them mentally before you begin.
5
What findings, if absent, would argue against them?
The pertinent negatives: findings you will
specifically look for and document as absent. Not incidentally
absent, but deliberately checked.
6
Am I examining purposefully, or performing a ritual?
If you cannot explain why you are examining a system or a
particular part of the body,
you should not be examining it yet. Or you
should revise your differential first.
The Mismatch
When history and examination do not agree
Diagnostic Red Flag
A history–examination mismatch is always diagnostically significant:
the question is what it is telling you, not whether to act on it.
Example: History strongly suggests heart failure. But examination
reveals no raised JVP, no edema, and clear lung bases. What now?
Is the history reliable?
Was the history taken completely? Did the patient minimize
symptoms? Is there a communication barrier? Take a collateral
history.
Is the patient already treated?
Diuretics will clear edema. Beta-blockers lower heart rate. A
patient on optimal heart failure therapy may have a normal
examination.
Was the examination adequate?
Was the patient fully exposed? Was JVP assessed at 45°? Were lung
bases examined posteriorly? Technique matters.
Is the hypothesis wrong?
A clear examination does not mean the history is false. It means
the initial hypothesis may be incorrect. Revise and retest.
Is there more than one diagnosis?
Co-existing pathology is common, particularly in older patients.
Two diseases can produce a picture that fits neither perfectly.
The mismatch itself is data.
Do not explain it away. Document it. Investigate it. A clinician
who ignores the mismatch has stopped thinking.
In short
The physical examination is most reliable when it is explicitly
hypothesis-driven, derived from a ranked differential, targeted to the system the
history implicates, and designed to seek both confirming signs and
deliberate pertinent negatives,
while remaining open to findings that require the hypothesis to be
revised.
Key Takeaway
Examination is not a ritual.
It is a tool to test your clinical
hypothesis.
Every sign you look for should answer a question generated by the
history.
Every sign you find (present or absent) should update your thinking.
History
Hypothesis
Examination
→ Diagnosis