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Clinical Examination
Written by Tim Sheppard MBBS BSc. Last updated 9/11/10

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What is a clinical examination?

Clinical examination is the bare bones of medicine. Short of actually taking a history, asking a patient what's wrong with them and finding out their side of the story, examination is one of the most useful skills that a doctor has. Nothing should distract from talking to the patient - the story that a patient gives can guide the kind of examination you perform - but when you get into examining a patient, you can find signs that a patient wasn't even aware of, and start to see a lot of clues that the body is offering you about a patient's state.

Examination should take an ordered and logical sequence to ensure that everything is done, and that each step is guided by the last. These steps follow simply through: inspection, palpation, percussion and finally auscultation. The stethoscope should be the last thing you pull out your pocket.


What is a differential diagnosis?

Given a single person's story (the different symptoms that they report) and the signs that show up from examination, it's unfortunately very difficult to come up with a hard and fast decision as to what's wrong with them. If a patient has a raised JVP with an absent waveform, you can be pretty confident that their problem is a superior vena cava obstruction. However, we don't often get things as simply as that - and even in that scenario, there are a range of options to explore. In each case, a full history and examination should narrow down the possible diagnoses from an infinite number to just a few. This list that you're left with is your differential diagnosis (or 'differential'), and it's this list that you need to explore with further investigations.


What is inspection?

The first thing you absolutely must do before anything else is look at the patient you're examining. You'll probably have noticed if there's blood pouring down their face, or if they're missing a limb, but it's not just these that you need to look out for - there's a lot of things that you've got to make sure of during this part, and if you miss them then you'll look like a complete fool!

Check for any scars, any leads or wires or tubes linked up to the patient, and for any obvious abnormalities. See if the patient looks distressed, if they're pale or blue ('cyanosed'), or if there's anything obviously wrong.

Inspection is very simply about looking at the patient, but it must not be missed. If you don't include looking at a patient before you start diving in with your hands, you'll miss something important and might even end up giving a wrong diagnosis. If a patient is unconscious and you try to take the radial pulse when he's had the radial artery removed, you won't be very popular for pronouncing him dead!


What is palpation?

Palpation is, quite simply, feeling. Palpating is feeling a patient's anatomy to see what's not quite visible, or to find out a little bit more about what is visible. Seeing some lumps in the neck - are they hard or soft? Feeling breathless - where's the apex beat?

Lots of essentially simple things which you can feel can answer some relatively complex questions and give you a great clue as to quite what's going on. The important thing is, don't forget to feel. It's easy to look at the patient and dive straight in with your stethoscope. The thing is, you might easily miss something by doing so - and, in many cases, auscultation isn't the best way to examine a particular feature.

Of course, this particular bit can feel a little bit uncomfortable for a patient - perhaps moreso than any of the rest of the examination - so make sure you're sensitive to a patient's feelings. This isn't groping, this is examination, and it should be clear that this is the case.


What is percussion?

Although when people talk about percussion they're usually talking about things like drums in an orchestra, percussion in the medical sense is related but different.

Percussion, or to percuss, refers to the art of striking the tip of ones curved (middle) finger against the middle phalynx (that is, the middle part of the finger) of the (middle) finger of the opposite hand. As the animation hopefully makes clear, it's like using your finger as a drum stick, and striking it against your other finger which is pressed flat (and stiffly) against a part of the body.

It is useful when examining the lungs, as lungs are full of air and therefore percussion sounds resonant - there is a hollow, 'round' sound to the noise produced, and may be clearly distinguished from the dull sounds when the contents below is solid (e.g. the liver coming up from the abdomen on the left hand side). Percussion of the lungs is done between the ribs.


What is auscultation?

Auscultation is simply the posh way of saying "listening with a stethoscope". It is a technique which importantly comes at the end of the examination, after inspection, palpation and percussion, and is used for listening in to what's going on beneath the skin.

The most obvious use of auscultation is for listening to heart sounds, since murmurs can often be really clearly diagnosed on the basis of auscultation. Even in this case, it's still important to perform the skills already mentioned first, since they can help you decide what to expect.

Auscultation can also be used to listen to breath sounds (for examination of the lungs) or bowel sounds (for examination of the abdomen).


What is a stethoscope?

A stethoscope is an incredibly clever device that is used for listening. There two types (acoustic and electronic) but it's the acoustic one that we're interested in because that's the one you'll see mostly in real life.

The instrument consists of a two-sided device attached to some hollow tubing that leads to two ear pieces; it's a distinctive design that you'll recognise if you see it, but it's also extremely well designed for its purpose. The two-sided device consists of a diaphragm on one side, and a bell on the other.

The diaphragm picks up higher pitched sounds via the vibration of a plastic disc, whose vibrations are then transmitted through the tubing to the ear pieces. This is the bit which is used for listening to most of the heart valves.

The bell similarly transmits its sound up the hollow tubing, but this time it forms a kind of metal tent over the body and transmits the vibrations generated in that air space straight up, rather than using the vibration of a plastic disc.

All this means that you've got the normal process of sound perception - i.e. via vibrations - but amplified using a stethoscope. Of course, the advancement of technology means that electronic stethoscopes are supposed to be able to pick up even more, but acoustic stethoscopes have been used for a long time to good effect, and their value should not be underestimated.


Further Reading