Atypical wound trajectory after a tangential pistol shot

Abstract

Three intermediate-range shots from a Browning, model 1955, 7.65 mm caliber, pistol were fired from the driver's seat of a car at a woman in the passenger seat. She sustained three wounds: An, ultimately fatal, penetrating head wound, a graze wound across her forehead, and a tangential, perforating, wound, with bullet entry over the medial sternum and exit through the right flank. Neither postmortem CT nor forensic autopsy discovered bony thoracic injuries or perforations of the thoracoabdominal cavities. There was pulmonary contusion in the medial lobe of the right lung and hemorrhage in the adipose tissue around the right kidney. The tangential bullet had left an almost 40-cm-long wound channel through a pronounced layer of subcutaneous fat. Based on 3D reconstructed CT-data determinations, a straight bullet trajectory between entry and exit wounds would have traversed the abdominothoracic cavities, right lung, and liver. The actual trajectory, however, described a prominent curve, without signs of deflection by bone. Postulated explanations for this unusual bullet track are that the woman was twisting her body in a dynamic scene when the bullet struck; further, due to its shallow angle of incidence on the skin, the bullet was deflected to an intracutaneous path. Additionally, soft tissue resistance may have caused the bullet to yaw. Caution should, thus, be exercised when reconstructing bullet trajectories solely from entry and exist wounds, also for bullet wounds through basically homogenous soft tissues.

Keywords: Autopsy; Bullet trajectory deflection; Gunshot; Murder; Post-mortem CT.

Fig. 1

The bullet retrieved from the passenger door sill. Ultimately, this bullet could be attributed to the tangential shot. The bullet was undamaged, apart from the typical grooves left by the pistol barrel

Fig. 2

Entry wound from the tangential shot over the sternum, 2.5 cm to the right of the midline

Fig. 3

Exit wound on the right flank

Fig. 4

Dissection of the subcutaneous adipose tissue on the right, anterior side of the torso. The bullet had only injured subcutaneous adipose tissue

Fig. 5

3D reconstructed CT datasets in volume-rendering mode, depicting the virtual wound trajectory and measurement of the straight connection between entry and exit wounds. After aligning the torso in the frontal plane, the cutting tool in OsiriX was used to cut the image along the bullet track. The parts of the torso that faced towards the lower left were eliminated. The ensuing cross section was then aligned in the frontal plane, and the exit and entry wounds were connected, using a measuring tool. The approximately 36-cm-long bullet trajectory can be seen to pass through the thoracic and the abdominal cavities

Fig. 6

Top: Depiction of the skeletal torso after 3D reconstruction in volume-rendering mode (bone window). Middle and bottom: Cross sections reconstructed in frontal plane. In the top image, the kyphosis of the thoracic spine can be recognized; the middle image shows narrowing of the intervertebral spaces and formation of osteophytes; in the bottom image sacroiliitis can be recognized. The findings are consistent with ankylosing spondylitis

Fig. 7

“Ballistic dummy” illustrating the reconstructed trajectories for the fatal penetrating bullet wound to the head (yellow) and the tangential shot (violet), in the court room