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Locus

What is a locus?

General definition

Non-anatomical loci

It is important to note that loci are not just anatomical locations. Loci are the sites of conditions, and the targets of investigations and interventions. Loci can therefore include body substances, fluids, and functions.

Non-normative loci

Occasionally, a non-normative body structure may refer to a locus.

What is not a locus?

Non-specific loci

General area words that refer to more than one locus

Loci that refer to a conjunction of several other areas will not be annotated.

Ordinal numbers and loci

Ordinals that modify a locus will not be included in that locus.

Loci modified by other words

Complex loci terms

  1. Body locations are often used as modifiers of other loci.
  2. Loci mentions that are formed by adding an adjective form of one locus to another locus, will be marked as a single locus in their entirety.
  3. Sometimes, complex chains of locations are used to modify each other. The annotation needs to mark each separate component, using laterality and sub-location signals where appropriate.

A recipe for dealing with complex loci and sub-locations

It is often difficult to decide how a complex locus term should be annotated. This recipe should be applied in these cases, to decide which part of the term or phrase should be annotated as what entity and what signal. It applies guidelines that are discussed elsewhere in a fixed order.

Step Description Examples
1. Identify a phrase that is about some Locus "Right upper quadrant of the abdomen"
"surface of the large intestine"
2. Find the major anatomical site. What is the most general, or most whole, bit of the phrase In "Right upper quadrant of the abdomen" this would be "abdomen".
In "surface of the large intestine" this would be "intestine"
3. Does the dictionary test apply? Is there a multiword part of the phrase that could be considered a term in a dictionary? If so, this becomes our major anatomical site. In "Right upper quadrant of the abdomen", there is none, so "abdomen" is the major anatomical site.
In "surface of the large intestine", "large intestine" would be found in a medical dictionary, so is the major anatomical site.
4. Are adjacent words anatomical or general? In "Right upper quadrant of the abdomen", none of the other words are anatomical terms, they are all general language.
In "section of the inguinal lymph node", the word "inguinal" is another anatomical locus - and so joins "lymph node" to become part of the anatomical site
5. Mark the main locus For "Right upper quadrant of the abdomen" this would be "abdomen".
For "surface of the large intestine", this would be "large intestine".
For "section of the inguinal lymph node", this would be "inguinal lymph node"
6. Mark other general location words as a single sub-location, excluding laterality For "Right upper quadrant of the abdomen", this would be "upper quadrant"
7. Mark any laterality For "Right upper quadrant of the abdomen", this would be "right"

Loci modifying conditions

Where a Locus is used to modify a condition, they should be annotated separately - taking into account the general guideline "dicitionary test" (i.e. if it appears in a medical dicitionary, annotate it)

Loci modifying investigations and interventions

Where a Locus is used to modify investigations and inteventions, they should be annotated separately - taking into account the general guideline "dicitionary test" (i.e. if it appears in a medical dicitionary, annotate it)