7fs in medicine
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7 Fs abdominal distension medicine mnemonic
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Here is the full breakdown of the 7 Fs in Medicine - the classic surgical mnemonic for causes of generalized abdominal distension:
The 7 Fs of Abdominal Distension
| # | F | Clinical Meaning |
|---|---|---|
| 1 | Fat | Obesity - the umbilicus is deeply inverted; this must be distinguished from intra-abdominal causes |
| 2 | Fluid | Ascites - commonly due to liver cirrhosis, congestive heart failure, malignancy, or nephrotic syndrome; umbilicus is everted and displaced downwards (Tanyol's sign) |
| 3 | Flatus | Gas/intestinal distension - absence of flatus suggests mechanical bowel obstruction or ileus; visible peristalsis may be present |
| 4 | Faeces | Constipation or large bowel obstruction - faecal loading palpable, indentable |
| 5 | Foetus | Pregnancy - always exclude in women of reproductive age |
| 6 | Fatal tumour (or Fibroid) | Intra-abdominal malignancy or large benign tumour (e.g. ovarian cyst, uterine fibroid, retroperitoneal mass) |
| 7 | Full bladder | Urinary retention - suprapubic dullness on percussion, dull to percussion in the midline |
Some sources list this as the 5 Fs, 6 Fs, or 9 Fs depending on how granular the breakdown is. The most widely taught version in surgical clinical examination includes the six above, with "Full bladder" or "False pregnancy" (pseudocyesis) often added as the 7th.
Key Clinical Distinctions
- Fat vs. Fluid: Fat - umbilicus inverted; Fluid (ascites) - umbilicus everted, flanks dull on percussion, shifting dullness positive, fluid thrill present
- Flatus vs. Faeces: Flatus - resonant on percussion throughout; Faeces - palpable indentable mass, especially in the left iliac fossa (sigmoid colon)
- Foetus: Confirm with urine hCG; never miss this before any investigation or procedure in a woman of childbearing age
- Fatal tumour: Hard, irregular, non-tender mass; associated weight loss, anaemia, and constitutional symptoms
S Das - A Manual on Clinical Surgery, 13th Edition notes: "Symmetrical distension may be due to fat, fluid, flatus, faeces or foetus. Distension due to obesity should be differentiated from distension due to intra-abdominal causes. In the former, the umbilicus is deeply inverted whereas in the latter the umbilicus shows varying degree of eversion."
Memory Aid
"Fat Fluid Flatus Faeces Foetus - Fatal tumour - Full bladder"
This covers the complete spectrum from benign (constipation, pregnancy) to life-threatening (bowel obstruction, malignancy, liver failure), making it a high-yield mnemonic for OSCE exams and surgical ward rounds.
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