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Sharp force injuries — incised wounds, stab wounds, defence and hesitation wounds
A sharp object produces two types of wound — an incised wound whose length on the skin exceeds its depth, and a stab wound whose depth exceeds its length — and a wound with clean margins and no tissue bridges is interpreted by its site, number and accompanying wounds.
Why it matters in the exam
The exam asks the student to distinguish suicide, assault and accident and to understand what can be concluded about the blade. Self-inflicted injury typically shows hesitation wounds: superficial, parallel, multiple cuts in an accessible area such as the wrist or neck, alongside one deep cut; clothing is sometimes lifted or moved aside first. Assault typically shows multiple stab wounds in different areas, through clothing, and defence wounds — cuts on the palms and between the fingers when the victim grips the blade, and cuts on the backs of the forearms when warding off.
What can be learned about the blade: a single-edged blade usually produces one sharp end and one blunt or squared end, and a double-edged blade two sharp ends; but movement of the blade in the wound and skin tension change the shape. The length on the skin also depends on angle and movement, so it does not exactly equal blade width, and wound depth can exceed blade length when tissue is compressed. Cartilage and bone, such as costal cartilage, preserve the blade profile better than skin. Wounds gape along skin tension lines (Langer's lines), so the margins are brought together before measuring.
Glass injury, for example in a fall through a window or glass door, produces many irregular cuts on the face, hands and forearms, sometimes with glass fragments in the wound. A practical point for the clinician: when examining a living victim, every wound must be documented before suturing — site, length, direction and ends — because the information is lost after treatment.
Key points
- Incised wound: length exceeds depth; stab wound: depth exceeds length.
- Self-infliction: superficial parallel hesitation wounds in an accessible area.
- Assault: multiple stabs through clothing and defence wounds.
- Length and depth do not measure the blade exactly; cartilage and bone keep its profile.
- Document every wound before suturing.
Summary table
| Type | Feature | Typical interpretation | Pitfall |
|---|---|---|---|
| Incised wound | Longer than deep, clean margins | Self-inflicted or assault | Confusing it with a scalp laceration |
| Stab wound | Deeper than long | Usually assault; severe internal injury | Inferring blade width from skin length |
| Hesitation wounds | Superficial, parallel, accessible area | Self-inflicted | Reading them as torture injuries |
| Defence wounds | Palms, between fingers, backs of forearms | Assault with resistance | Missing them on examination |
| Glass wounds | Multiple, irregular, face and hands | Fall through glass | Reading them as a knife assault |
A free exam question
בן 40 , לאחר דקירת סכין בגלוטאוס מימין סימנים חיוניים תקינים . מיקום החתך בתמונה נצפה דימום שפסק לאחר לחץ מקומי . בדיקה רקטלית ללא עדות לדם טרי. סטיק שתן RBC +3 . מה הצעד הבא? (the question as examined, in Hebrew)
- א. SIGMOIDOSCOPY באישפוז
- ב. WOUND EXPLORATION
- ג. CT ANGIOGRAPHY + CYSTOGRAPHY
- ד. LAPAROYOMY
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Sources
- Knight's Forensic Pathology, 4th edition (2016) — Sharp and cutting-edge wounds
- Simpson's Forensic Medicine, 14th edition (2020) — Injury assessment and interpretation
- Spitz and Fisher's Medicolegal Investigation of Death, 5th edition (2020) — Sharp force injury
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.