Q3 LONG ANSWER 10M ★ High-yield

Describe lacerated, incised and stab wounds and distinguish between them.

Forensic Medicine · 2nd Professional — Para-Clinical

Lacerated Wounds

A laceration is a tear or split of the skin and underlying tissues produced by blunt force, in which the tissue is crushed, stretched or torn rather than cut.

Type	Mechanism and example
Split laceration	Crushing of the skin between the weapon and underlying bone — the scalp, eyebrow, cheek bone, iliac crest and shin. This is the type most often mistaken for AN incised wound, because over bone the margins may look deceptively clean
Stretch laceration	Overstretching of the skin, as when a limb is run over or a bone fractured and the fragment tears the skin from within
Avulsion	Separation of the skin from underlying tissue by a grinding or shearing force — a vehicle wheel; "flaying" or "degloving" of a limb
Tear laceration	From an irregular projecting object — a door handle, a broken bone end, or a projection on a moving vehicle
Cut (chop) laceration	From a heavy weapon with a relatively blunt edge

Feature	Lacerated wound	Incised wound
Causative weapon	Blunt	Sharp-edged
Margins	Irregular, ragged, abraded and contused, often inverted	Clean-cut, regular, everted, not abraded or contused
Tissue bridges across the depth	Present — strands of vessels, nerves and connective tissue crossing the floor, because they are more resistant than the surrounding tissue and are stretched rather than divided. This is the single most reliable distinguishing feature	Absent — everything is divided cleanly at the same level
Hair at the margin	Hair bulbs crushed but hair not cut — the follicles are torn out intact	Hair cleanly cut at the margin
Dimensions	Depth variable and irregular; wound gapes irregularly	Length exceeds depth; wound gapes in a regular spindle shape from elastic retraction
Bleeding	Less — vessels are crushed and retract, so they thrombose	Profuse — vessels are cleanly divided and cannot retract
Foreign material	Grit, dirt, glass, paint and hair are commonly present in the depths	Usually absent
Healing	Slow, with infection common; heals with an irregular scar	Rapid; heals with a linear scar

CLINICAL PEARL

Tissue bridges settle the question, and a scalp split will fool you otherwise. A blow to the scalp with a rod crushes the skin against the skull and produces a wound whose margins can look almost clean — and it is regularly certified as an incised wound, converting a beating into a stabbing. Retract the margins and look into the floor: strands of vessel and connective tissue crossing the depth mean blunt force, whatever the edges look like.

Incised Wounds

Definition — a clean cut through the tissues produced by drawing a sharp-edged weapon across the skin, in which the length exceeds the depth
Shape — spindle-shaped (elliptical) when gaping, because of the elastic retraction of the divided skin; the gaping is greatest when the wound runs across the LANGER lines and least when parallel to them, so the degree of gaping reflects the direction of the cut rather than the force used
Direction of the cut is shown by tailing — the wound is deeper at the point of commencement and becomes shallower, ending in a superficial "tail" at the termination, because pressure is greatest at the start and is released as the weapon is drawn away
Bleeding is profuse, and the wound may be fatal from haemorrhage even when small, particularly in the neck
Chop wounds — produced by a heavy weapon with a sharp-ish edge: an axe, a hatchet, a sword, a chopper or a heavy daab. They combine features of both: the margins are cut but also bruised and abraded, the wound is deep, and there is characteristically an underlying fracture of bone with a corresponding cut or notch, which may retain a toolmark identifying the weapon

Stab (punctured) Wounds

Definition — a wound produced by the penetration of a pointed weapon, in which the depth exceeds the length and breadth
Weapons — a knife or dagger; and also a screwdriver, nail, scissors, needle, arrow, spear, glass fragment or any pointed object
The shape of the skin wound reflects the weapon — a single-edged blade produces a wound with one sharp and one blunt (rounded or squared, "fish-tail") angle; a double-edged blade produces both angles sharp; a cylindrical weapon such as a nail produces a rounded or slit-like wound; and a screwdriver or square-sectioned instrument produces a characteristic cruciate or rectangular defect
The shape is altered by Langer lines, so a single stab may gape into an ellipse and mislead; the wound should be approximated and then measured, and the true dimensions recorded
Depth of the wound and length of the blade — the depth of the track is not necessarily the length of the blade. It may be greater, where the abdominal or chest wall was compressed on impact; or less, where the weapon was not fully inserted. So the doctor may state a minimum blade length and give the width from the wound, but cannot state the blade length precisely
The direction of the track is recorded in three dimensions from the skin surface — upward or downward, medial or lateral, front to back — with the body in the anatomical position, and it may indicate the relative positions of assailant and victim
Multiple stab wounds favour homicide; and a stab wound may be fatal from haemorrhage, from injury to a vital organ, from air embolism (neck veins), or from pneumothorax

Determining the Weapon and the Direction

Question	What the wound shows
Blunt or sharp weapon?	Tissue bridges, abraded contused margins and crushed hair bulbs indicate blunt; clean margins, no bridges and cleanly cut hair indicate sharp
Single- or double-edged blade?	One sharp and one blunt or "fish-tail" angle indicates single-edged; both angles sharp indicates double-edged
Width of the blade?	The length of the stab wound after the margins are approximated — not as it gapes
Length of the blade?	A minimum only, from the depth of the track. The track may be deeper than the blade where the body wall was compressed, or shorter where the weapon was not fully inserted
Direction of an incised wound?	Tailing — deeper at the commencement, tapering to a superficial tail at the termination
Direction of an abrasion?	Epidermal tags heaped at the far (terminal) end
Direction of a stab track?	Recorded in three planes from the skin surface with the body in the anatomical position — upward or downward, medial or lateral, front to back
Was great force used?	Cannot be estimated from a stab wound — a sharp blade penetrates the chest or abdomen with very little force. Force can be inferred only from bone injury and crushing
Which weapon among several produced?	The wound is consistent with a class of weapon; only a toolmark on bone or cartilage can approach identifying an individual weapon

Applied Aspects

Look into the depth of every wound for tissue bridges before calling it incised; the scalp, eyebrow and shin produce split lacerations that look cut, and the distinction changes the weapon and therefore the case
Photograph and describe before suturing in the living; once the wound is repaired its character is gone permanently, and a surgeon who sutures first should be asked to describe what was seen
Record the angles of a stab wound, and approximate the margins before measuring; the number of sharp angles indicates whether the blade was single- or double-edged
State the blade length as a minimum, never as a figure; compression of the body wall allows a track deeper than the blade, and this is a standard cross-examination point
Look for an underlying bone injury in a chop wound; the notch may retain a toolmark that identifies the individual weapon, and it should be preserved rather than sawn through
Do not estimate the force used from the depth of a stab; a sharp blade penetrates the chest or abdomen with very little force, and courts are repeatedly told otherwise
The degree of gaping reflects the Langer lines, not the force; a wound across the lines gapes widely and one parallel to them barely at all
Incised wounds bleed profusely and lacerations less, because crushed vessels retract and thrombose while cleanly divided ones cannot — which explains why a small neck incision can be rapidly fatal
Preserve the bone in a chop wound rather than sawing through the notch; the toolmark may identify the individual weapon
Approximate the margins before measuring a stab wound; the gaping dimension is not the width of the blade
Look for foreign material in the depths of a laceration — grit, glass, paint, hair — which may link the wound to a particular surface or vehicle
Give the blade length as a minimum only; compression of the chest or abdomen allows a track deeper than the weapon, and this is a standard cross-examination point

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