What forensic indicators distinguish a graze/wedge wound to the ear from full-penetration bullet wounds in open-source imagery?

1. Visible surface morphology: shallow abrasion and linear grazing versus central defect

Graze or tangential injuries typically show a superficial, often linear or crescentic abrasion with adjacent small parallel abrasions or “wedge” features where the bullet glanced off skin or cartilage, rather than a round, well‑defined central hole; this pattern is repeatedly described in forensic literature and photographic atlases of grazes ^{[1] [5]}. By contrast, penetrating entrance wounds usually present a central substance defect approximating the projectile diameter with an abrasion rim produced by friction between the bullet and skin, sometimes showing a comet‑tailed abrasion if the approach angle is oblique ^{[2] [6] [7]}.

2. Cartilage behavior: tearing and surface laceration versus perforation

The ear’s thin cartilage means a tangential hit often produces surface laceration or partial‑thickness cartilage tears and buckling consistent with energy transfer without a full track through deeper tissues; graze studies and experimental porcine models illustrate how low‑angle impacts produce laceration‑like injuries rather than full perforation ^{[5] [8]}. A full‑penetration wound will typically perforate cartilage and soft tissue, often producing a through‑and‑through defect with a measurable depth and, in clinical/autopsy contexts, an internal wound tract visible on dissection or MDCT ^{[9] [3]}.

3. Surrounding residues and range indicators: absence in grazes, possible presence in penetrations

Entry wounds, especially at close ranges, may show gunshot residues, soot, stippling, or a “grease” or dirt ring from the bullet that help identify an entrance and the approximate range; grazes that do not penetrate will lack internal powder tattooing but may still carry superficial bullet wipe or tiny abrasions from glancing contact ^{[2] [6] [8]}. In open‑source imagery, detection of subtle soot or stippling is unreliable unless high‑resolution macro photographs or clinical images are available ^{[7] [4]}.

4. Three‑dimensional cues and dynamic evidence: angle, tissue displacement, and video frames

The angle of incidence inferred from wound shape (comet tails, abrasion orientation) and surrounding tissue deformation can indicate whether a projectile glanced off or entered; experimental work shows low incident angles (≈6–7°) produce graze‑like lacerations while steeper angles produce distinct entry holes ^[8]. Sequential video frames or multiple photos that show evolving bleeding, wound depth, or secondary movement of tissue increase confidence in classification versus a single static, low‑quality image ^{[8] [3]}.

5. Radiology and forensics: the decisive adjunct when available

Radiographs or postmortem CT that show retained projectiles, exit fragments, or a wound track are decisive evidence of penetration or perforation and can resolve contradictions when surface findings are ambiguous ^{[3] [10]}. Open‑source outlets rarely include such imaging; absence of radiology in public media should be treated as a limitation, not proof of absence of penetration ^{[4] [3]}.

6. Practical caveats: misinterpretation risks and need for expert correlation

Photographic artifacts, clothing, blood obscuration, decomposition, and the ear’s complex surface can mimic or mask abrasion collars and small grazes, and experimental/clinical variability (weapon type, velocity, angle) means morphology overlaps; forensic pathologists therefore avoid definitive classification from a single external image unless corroborated by radiology, autopsy, or controlled experimental analogues ^{[4] [2]}. Alternative explanations — fragment rebound, multiple projectiles, or partial penetration — are documented and must be considered when entrance/exit counts or wound shapes don’t match simple models ^{[10] [11]}.