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Comment by HPsquared | Hacker News Reader

If you're inside a ship, it's often hard to say what way around you are: "left" and "right" have utility for the perspective of a person onboard. Port and starboard are the onboard equivalent of North/South/East/West when walking on land, especially if you're inside a building with no windows for external reference.

This is unlike for a doctor, where it's obvious which side is which: you can see the patient.

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> This is unlike for a doctor, where it's obvious which side is which: you can see the patient.

This isn’t always true and it’s not always obvious.

For example with imaging - axial slices of the patient through symmetrical structures. The brain, lower abdo, a single leg or arm etc, etc. There are conventions in image display for a reason - it is not obvious.

For axial slices, as an observer, you are positioned as though at the foot of the patient’s bed. Your right is the patients left.

I don't know, when you're talking about "the right arm", it seems obvious that it's the patient's right arm and not the arm that you see on your right when you're looking at the patient. I don't think you need to go to medical school to understand that.

Assumptions like this is how errors are made.

Don't make assumptions, codify it.

You're right that "the left lung" should obviously be the lung on the patient's left. However, can you look at the image below and immediately identify which is the "left" lung?

https://scratch.rprosperoglobal.duckdns.org/lungs.png

I think I can, maybe. However I’m a radiographer and pictures like this are my job.

The orientation is screwed up and images should almost never be displayed like this.

If the patient’s organs are in non-standard locations (situs inversus, dextrocardia etc), something very bad will happen when orientations are messed with. Use standard orientations and label the images.

I fully agree with you. I was mostly posting as an example that "left is the patient's left" is not sufficient without other standards (like image orientation).

And that went straight over my head.

Your point was well made.

...you just expect random readers to know how lung looks on (i assume) MRI, from (I assume) top ?

I'd also assume it would be simple to spot just because the image is always took from the same direction so the narrow part points out to front/back of the patient

It’s obvious 99% of the time, but that 1% equates to a lot of fatal errors.

Shouldn't doctors simply use the Greek or Latin words for left and right?

Latin: sinister and dexter, I think they are used for parts of organs (eg liver); one source notes occulus sinister being used in the abbreviation OS for left eye.

Greek dexios and aristeros ... well dexter come from dexios", as does the chemical suffix -dextrin. Aristeros* is a euphemism, it means something like "best" (I wonder if that's the origin of 'put your best foot forward') ... I'm told that left-sided things were unlucky to the Greek speaking peoples and Greek language apparently compensated by describing that position positively.

The "left-side are unlucky" thing affects the Latin example as well as the Greek, at the very least in the way that English derived words get used: compare "dexterous" (modern English connotations of "able, agile") versus "sinister" (modern English connotations of "evil, subversive").

It's an interestingly deep rabbit hole in language etymology just how much "left" gets besmirched and "right" gets positive connotations. (The fact that "right" is also a synonym in English for "correct" being another bit of evidence.)

It just seems like an old convention that has stuck, seem'm much simpler to anyone not familiar with ships to say 'ships left' or 'ships right' than to have new words. We don't do this with cars. You have a left rear door, not a port rear door.

> We don't do this with cars. You have a left rear door, not a port rear door.

“Driver side rear door” or “passenger side rear door” are pretty common, at least in the US and UK, where they mean the opposite.

“Nearside“ (passenger side nearest curb in a right-hand drive vehicle driving on the left) and “offside” (driver side furthest from curb) are also used in the UK.

If you ever went 4x4 driving, you use driver / passenger to indicate the direction someone has to go to. This is because the navigation often is done from someone standing outside the car, where using left/right can be rather confusing.

In UK a [experienced, older?] driver gives another driver instructions with "right hand down" and "left hand down". That is, you give directions to move the steering wheel.

I've the vaguest recollection that sailing/steam boats used to say which side to move the wheel towards to steer; that begging opposite of the way the boat will go??

For repair instructions this actually causes a lot of confusion for someone in a right hand drive market. Half the time the repair instruction gets it wrong and would have been better saying left or right. Occasionally it is correct though if dealing with a part that's different in each market.

I don’t know how widespread this is but I don’t do this for the very reason you bring up with differences between countries, I drive in both the UK and Canada most years.

I guess some could argue that we do have some special vocabulary for cars too.

E.g. you don't call it the front/back door, you call it the bonnet/boot (or maybe hood/trunk depending where you're from) though that probably is stretching the definition of a door a little bit... but then you also have nearside and offside for passengers/drivers side, though that's probably a bit more of a technical term.

I always get confused by nearside and offside. Is it "near to the driver" or "near to the roadside"?

Near the roadside.

> though that probably is stretching the definition of a door a little bit...

It is, but then so is the stupid "3-door" / "5-door" / etc. car classification, which is really 2-door / 4-door / etc. with the trunk being counted as additional door for some reason.

I think it makes sense for hatchbacks, where there's no real trunk/passenger cabin separation.

The trunk is considered a door when it opens into the main cabin instead of a separate compartment.

Cars are small and for the most part everyone in the car faces the same direction as the car itself. When you have a ship, you have 3 frames of references to contend with (self, ship, cardinal)

Four, actually. You also have the wind frame of reference, which is actually the most important (for sail boats). You don't turn left or right, you turn upwind or downwind.

For wind there is leeward (downwind) and windward (upwind). I don't think there are common terms for the 2 crosswind directions though?

I'm not familiar with sail vocabulary in English, but in Portuguese there is only downwind (sotavento) and upwind (barlavento). Functionally you don't need the other two, so I imagine it's similar in English.

> you can see the patient.

Often not true. In any sort of imaging it can be ambiguous what way the patient is facing

Yup. Port and starboard, along with forward and aft are in reference to the center-line of the ship from the perspective of being aft and looking forward. Looking at a top down of the ship from where forward and the forecastle are up, it is left (port) and right (starboard).

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