Understanding Medical Terminology – Colour, Position and Quantity

Roots of Colour

Understanding medical terminology – colour, position and quantity. These word roots are essential for accurate descriptions of medical and anatomical items.

Many words used to describe the colour of something in the medical world exist. Both Latin and Greek roots are used for the most part with the exception of yellow which also has a French prefix. These roots are combined with suffixes to describe many things. Here’s the list of prefixes:

Colour	Greek Root	Latin Root	French Root
Black	Melan-	Atr- or Nigr-	–
Blue	Cyan-	Cerule-	–
Gold	Chrys-	Aur-	–
Grey	Poli-	Can-	–
Green	Chlor-	Vir-	–
Purple	Porphyr-	Purpur- or Purpureo-	–
Red	Erythr- or Rhod-	Rub-, Rubr- or Ruf-	–
Red-Orange	Cirrh-	–	–
Silver	–	Argent-	–
White	Leuc- or Leuk	Alb- or Cand-	–
Yellow	Xanth-	Flav-	Jaun-

Once you know these roots you will spot them in medical words and in Latin names for species. You’ll find that you recognise some of these words already. So let’s take a look at a few examples:

Cells

The suffix ‘-cyte’ refers to a body cell. So melanocytes (black cells literally) are the cells in the skin that contained melanin pigment. Melanoma means a cancer of these cells. Erythrocyte translates literally as ‘red cell’ so it’s referring to red blood cells. Leucocyte (also spelled leukocyte) is a white cell – white blood cells.

-osis

This suffix means ‘condition, disease process or increase’ and is used a lot. Cyanosis means a blue discoloration of the skin/lips due to hypoxia (low oxygen). You describe someone as ‘cyanotic’ which is the adjective form. Poliosis describes a localised patch of grey or white hair. Chlorosis describes a yellow/green tinge to the skin in cases with severe iron deficiency.

Bile Pigments

Two of the main bile pigments use the latin roots. Bilirubin is the red bile pigment. It is produced in the liver by breaking down dead red blood cells. Another bile pigment, which is responsible for the green/yellow colour is biliverdin. You can guess that the prefix ‘bili’ relates to the bile.

These pigments build up in the body due to liver or gall-bladder disease or a condition causing high destruction of red blood cells. This leads to the bile pigments moving into the body tissues and causing a colour change. It’s usually first noticable in the white of the eye (sclera) but eventually will change the skin and mucous membranes. This is called ‘jaundice’ and uses the French root. A fancy way of saying you look like a Simpson.

Albumin

Albumin is a protein that is found in the blood. It has a lot of functions, including transporting other substances and osmotic pressure to maintain the right balance of fluid between the cells and the circulation of the body. It is also found in egg whites, hence the name!

Porphyria

Porphyria is a disorder where porphyrins build up in the body. Porphyrins are used to make haem, the protein and iron molecule within red blood cells that carry oxygen around the body. Porphyria causes seizures, vomiting and all kinds of horrible symptoms, but it’s usually genetic.

One of the key characteristics is the change in urine colour in response to sun exposure. The urine will turn purple. Porphyria causes an extreme sensitivity to sunlight. It has been theorised that this might explain some aspects of legends around vampires and werewolves but this may not be true. There are a number of historic royals who are suspected to have had this disease, including Mary, Queen of Scots and Maria I of Portugal. Vincent Van Gough, the artist, may have suffered from acute intermittend porphyria.

Medical Terminology – Roots Of Position

These roots describe locations in a lot of adjectives and nouns in the medical world. They can tell you where something is located, or which isomer of a molecule is present. Isomers are molecules that are identical in terms of properties, except for the direction they rotate polarised light. Such as ‘levothyroxine’ which is an L isomer of thyroxine (T4), the main thyroid hormone. Only the L isomer is active, the D isomer has no effect on the body.

Description	Greek Root	Latin Root
Around/Surrounding	Peri-	Circum-
Internal/Within	Endo-	Intra-
Left	Levo-	Laev- or Sinistr-
Middle	Meso- Mes-	Medi-
Right	Dexi-	Dex-, Dextr- or Dextro-

So here’s a few examples: Pericardium is the tough capsule that surrounds the heart. It contains a small amount of fluid and is there to protect the heart. So ‘peri-‘ means around and ‘cardium’ means the heart.

Endometriosis

Endometriosis is a topical condition right now, because it takes an average of seven years to diagnose. As we mentioned before the suffix ‘-osis’ means condition or disease. Endometrium is the term for the lining of the uterus, the part that is shed every monthly cycle. ‘Endo-‘ means inside and ‘-metrium’ is related to the uterus. So endometriosis means that the cells normally found inside the uterus start growing in other places in the body and cause severe symptoms. It’s extremely debilitating.

Mediastinum

Mediastinum is the anatomical term for the space between the lungs. The middle of the chest, in essence. This is where there are mediastinal lymph nodes, the thymus and the heart. A rare but interesting condition is ‘dextrocardia’ where the heart is on the right side of the chest instead of the left. There’s even an extreme version called ‘situs inversus’ where all the organs are flipped left to right and mirrored.

Medical Terminology – Quantity or Amount

There are a few prefixes that denote the number of something or the amount of something. You will encounter these a lot in medical terminology and other scientific writing. There is one that could trip you up but we’ll get to that.

Description	Greek Root	Latin Root	Other (French)
Double	Diplo-	Dupli-	–
Equal	Iso-	Equi-	–
Few	Oligo-	Pauci-	–
Half	Hemi-	Semi-	Demi-
Many/Much	Poly-	Multi-	–
Twice	Dis-	Bis-	–

One you’ve probably heard a lot is ‘isotonic’. This term describes a fluid that has the same concentration as another. Intravenous fluids are usually isotonic, meaning they have the same concentration of electrolytes as the blood.

Hemivertebrae is a condition where the vertebrae of the spine don’t form properly, only half of the vertebrae is present. It can cause all kinds of pain and difficulty. It’s congenital, meaning it is present from birth.

When writing instructions for medication, we use a shorthand Latin acronym. Not for patients, of course, but between doctors, nurses and pharmacists they will use these. B.I.D stands for bis in diem – that means twice a day.

‘Equi-‘ means equal in Latin. Don’t get caught out by this anatomical term! The ‘cauda equina’ describes the tail end of the spinal cord where a bundle of nerves extend past the end of the cord. It looks like a horses tail so in this case ‘equina’ is referring to ‘equine’, that is to horses. ‘Cauda’ refers to the tail – a term used a lot more in animal medicine than humans.

Thanks for reading, I hope you enjoyed this rundown of medical terminology – colour, position and quantity. If you missed the previous ones you can find them here and here. Subscribe to be updated when a new post is live and find me on my social media channels.

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