Finding the Appropriate Class Number
Subject Classification Preference
Works are generally classified in an order of preference:
- Disease
- Organ or region chiefly affected
- Special form of therapy, diagnostic procedure, or environmental condition as a cause of disease, etc., if disease is mentioned peripherally
Disease
Some organ disease headings have separate class numbers. In addition, some may have additional class numbers for subtopics such as diagnosis or therapy.
Example
Notice that "Breast Diseases" show four class number subtopics.
Class general diseases of an organ in the class number for the organ if no separate number is available, unless otherwise instructed. When works are about multiple diseases (up to three), go with the disease given most emphasis or the one discussed first.
Exception
Diagnosis of diseases of famous persons, derived from records, memoirs, letters, portraits, etc. is classed in WZ 313 "Biographical clinics (Diagnosis of diseases or psychological conditions of famous persons) (Cutter from name of biographee; collective, cutter from main entry)."
Organ/Region
A work dealing with a particular region of the body or an organ is classified with the region or organ system, depending on the emphasis of the work.
Example
General works on the head and neck are classed with the "Musculoskeletal System" in the WE schedule.
| Class Number | Caption |
|---|---|
| WE Musculoskeletal System Head and Neck |
|
| WE 700 | Head and Neck |
| WE 705 | Head. Face |
| WE 705.5 | Rhytidoplasty |
| WE 706 | Head and neck injuries |
| WE 707 | Head and neck neoplasms |
| WE 708 | Neck |
Specific Cases
- Dental problems and procedures - When the emphasis concerns dental problems and procedures related to the mouth, teeth, and jaws, the work is classed in WU with "Dentistry."
- Otolaryngological problems and procedures - If the emphasis concerns the otolaryngological problems and procedures, related to the ear, nose, and throat, the work is classified in the WV schedule with "Otolaryngology."
- Brain and associated organs - If the emphasis is on the Brain and associated organs, the work is classified in WL with the "Nervous System."
Procedures
If the work is about a special form of therapy, diagnostic procedure, or environmental condition as a cause of disease, etc., and the disease is only mentioned in the context of the primary subject (the therapy, etc.), classify as always for the primary subject.
Example
A work on proton therapy physics written by a radiologist is classed with the therapy at WN 250.5.P7 rather than QZ 269 with radiotherapy of neoplasms.
Generally, class the reversal of a medical procedure in the same number as the procedure itself, if no separate number exists.