A.V.
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During the Croatian homeland war (1991-1995), hundreds of patients with gunshot wounds were treated in the Department of Surgery at Karlovac General Hospital. Understanding of the wounding mechanisms and characteristics of these injuries is vital for the choice of optimal surgical treatment. Even though the principles of war surgery are clear and explicit, 1-4 recognition of wounding mechanisms is very helpful for management because the effects of individual types of bullets can be predicted. Unfortunately, information about the type of weapon and bullet that had caused the wound is usually limited or inaccurate. However, in some cases, bullet type can be established before surgical treatment. In two patients treated for gunshot wounds in the Department of Surgery at Karlovac General Hospital, the information about the weapon and bullet type could be obtained (AK 74, 5.45 X 39 nun). Both injuries were uncomplicated soft tissue lower extremity wounds. The wound profile method5,6 emerged as an appropriate method to predict wound extent because it provides a clear and simple outline of a particular missile's effects. According to this method, significant wounds occur even in uncomplicated extremity hits (Fig. 1),7 and significant yaw is present at approximately 8 cm of the wound track and extensive temporary cavitation is visible after only 3 to 4 cm of the missile path. Considering the length of the wound channels in our patients, we expected to find larger exit wounds. Because surgical exploration of the wounds of our patients did not quite confirm the expected wound extent, a terminal ballistic trial was performed to study the effects of this missile on an experimental model.
Materials and Methods
The effects of missiles fired from the Russian AK 74 assault rifle (5.45 x 39 mm) were studied. The ammunition was manufactured in Russia in 1992. Missiles were fired into 20 gelatin blocks that were used as tissue simulants, with one shot fired into each block. Shots were fired from a range of 8.5 in (distance from the muzzle to the front face of the gelatin block). Missile velocities were measured using a chronometer composed of two optoelectric modules with infrared transceivers at a distance of 2 in. Gelatin blocks measured 0.47 length) x 0.22 (width) x 0.16 (height) in. The blocks were stored at 4 deg C and fired at within 1 to 2 minutes after their removal from the refrigerator. The blocks were made as 20% (v/v) aqueous solution of gelatin powder made by Kemika (Zagreb, Croatia; physical properties, 70-100 Bloom). By weight, it was a 15.3% solution (1 L of gelatin powder = 720 g). The missile track was filmed using a television camera with a high-speed shutter (DiCam2, PCO Computers). Images of the gelatin block and of the position of the missile were digitalized and stored in the computer memory. After the exit of the missiles, radiographs were made of the blocks to detect possible fragmentation of the bullets.
Results
The mean impact velocity of the missiles, measured on a sample of 20 blocks, was 887.5 /- 15.2 m/s. All bullets exited the blocks. Analysis of images acquired by high-speed photography and radiography showed that none of the missiles deformed or fragmented. The missiles were found to be unstable during their path through the gelatin blocks in two ways: the path of the missile was not linear, and it was erratic and unpredictable. The bullets were found to curve to the top, bottom, and the sides of the blocks; the longitudinal axis of the trajectory was found to deviate from the long axis of the bullet.
Images obtained with the high-speed camera revealed significant yaw at 8 to 11 cm of bullet penetration, whereas maximum disruption occurred between 15 and 22 cm of the trajectory. Then it gradually decreased toward the bullet's exit point. A large temporary cavitation was visible after considerable instability of the bullet appeared (at 8-11 cm of the trajectory).
http://findarticles.com/p/articles/mi_qa3912/is_200112/ai_n9010648/
Materials and Methods
The effects of missiles fired from the Russian AK 74 assault rifle (5.45 x 39 mm) were studied. The ammunition was manufactured in Russia in 1992. Missiles were fired into 20 gelatin blocks that were used as tissue simulants, with one shot fired into each block. Shots were fired from a range of 8.5 in (distance from the muzzle to the front face of the gelatin block). Missile velocities were measured using a chronometer composed of two optoelectric modules with infrared transceivers at a distance of 2 in. Gelatin blocks measured 0.47 length) x 0.22 (width) x 0.16 (height) in. The blocks were stored at 4 deg C and fired at within 1 to 2 minutes after their removal from the refrigerator. The blocks were made as 20% (v/v) aqueous solution of gelatin powder made by Kemika (Zagreb, Croatia; physical properties, 70-100 Bloom). By weight, it was a 15.3% solution (1 L of gelatin powder = 720 g). The missile track was filmed using a television camera with a high-speed shutter (DiCam2, PCO Computers). Images of the gelatin block and of the position of the missile were digitalized and stored in the computer memory. After the exit of the missiles, radiographs were made of the blocks to detect possible fragmentation of the bullets.
Results
The mean impact velocity of the missiles, measured on a sample of 20 blocks, was 887.5 /- 15.2 m/s. All bullets exited the blocks. Analysis of images acquired by high-speed photography and radiography showed that none of the missiles deformed or fragmented. The missiles were found to be unstable during their path through the gelatin blocks in two ways: the path of the missile was not linear, and it was erratic and unpredictable. The bullets were found to curve to the top, bottom, and the sides of the blocks; the longitudinal axis of the trajectory was found to deviate from the long axis of the bullet.
Images obtained with the high-speed camera revealed significant yaw at 8 to 11 cm of bullet penetration, whereas maximum disruption occurred between 15 and 22 cm of the trajectory. Then it gradually decreased toward the bullet's exit point. A large temporary cavitation was visible after considerable instability of the bullet appeared (at 8-11 cm of the trajectory).
http://findarticles.com/p/articles/mi_qa3912/is_200112/ai_n9010648/
