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Underbelly injury based identification of the driver in a three-rider motorcycle accident
Legal Medicine 18 (2016) 20–24
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Legal Medicine journal homepage: www.elsevier.com/locate/legalmed
Case Report
Underbelly injury based identification of the driver in a three-rider motorcycle accident Shengxiong Liu a,c, Zhiyong Yin b,c,⇑, Sen Su b,c, Kui Li b,c a
Department of Biomedical Engineering, School of Pharmacy & Bioengineering, Chongqing University of Technology, Chongqing 400054, China Department 4, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China c Chongqing Bayi Judicial Identification Center for Traffic Accident, Chongqing 400042, China b
a r t i c l e
i n f o
Article history: Received 25 October 2015 Received in revised form 18 November 2015 Accepted 23 November 2015 Available online 24 November 2015 Keywords: Motorcycle accident Driver identification Groin injury Perineum injury Underbelly injury
a b s t r a c t This paper presents a three-rider motorcycle accident which took place in a suburb of Chongqing China. In the accident, the motorcycle impacted the terminal of a bridge footpath and led to two riders died and one rider injured. After the accident, one rider received injuries around the groin area including the underbelly area and the perineum area. Another rider suffered from injuries only on the perineum areas. In medico-legal judgments, injuries around the groin area also called groin injuries in victims of motorcycle accidents are usually regarded as ‘‘fuel tank injuries” which are commonly found in drivers. But, the injuries around the groin area are sometimes confused with the perineum injuries. Therefore, the perineum injuries are often wrongly reckoned as the ‘‘fuel tank injuries” and used to identify the drivers too. Actually, passengers can sometimes suffer from perineum injuries in many head-on impacting motorcycle accidents. It is of vital matters to understand the differences between groin injuries and perineum injuries so that the real driver who should be responsible for the accident can be recognized. In this paper, the three-rider motorcycle accident was presented and the injury information of the three riders was studied in order to distinguish the real driver from the riders. We consider that the groin injury has some differences with the perineum injury and the latter should not always be related to the driver especially in high-speed head-on impacting motorcycle accidents. In addition, the injury on underbelly areas is important to identify the driver. Crown Copyright Ó 2015 Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction In two-rider or three-rider motorcycle accidents, it is difficult to distinguish the driver from the passengers. However, being able to do so is important for medico-legal judgment [1]. The difficulty in the driver’s identification is that all riders are usually thrown from the vehicle and have few characteristic injuries for each seated location. Valerie et al. reported that there is no statistically significant difference in the severity of injuries between motorcycle riders and pillions of matched pairs [2]. In fact, Injury around the groin area of the victim, known as ‘‘fuel tank injury” is one of the few characteristic findings [3]. But, the injuries around the groin area are often confused with the perineum injuries. According to previous reports, injuries around the groin area including the perineum area, known as fuel tank injuries, were always related to the driver but never to the passengers [1,3,4]. In 2007, Ihama et al. [5] ⇑ Corresponding author at: Department 4, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China. E-mail address: [email protected] (Z. Yin).
presented a rare case of a two-rider motorcycle accident in which the driver suffered from groin injury and the passenger met with the injuries on his perineum area. And the authors made much effort and successfully identify the driver through the traumatic testicular dislocation [5]. For a motorcycle, the surface of the fuel tank is always obliquely upward and forms an obtuse angle with the surface of the saddle. The ‘‘fuel tank injury” usually appears in relatively high-speed head-on motorcycle impacts. During this kind of impact, the motorcycle can fiercely be stopped by the external obstacle. However, because of the powerful inertia, the riders will maintain their initial speeds and continue to move forward with their straddle postures gliding sharply along the surface of the saddle and then strike heavily on the surface of the fuel tank. Consequently, the groin area of the driver who sits nearest to the fuel tank will be injured with high probability by the upper and bilateral surfaces of the fuel tank resulting in ‘‘fuel tank injuries”. In a real two-rider motorcycle accident, it is really difficult to find the injury differences between the riders and then identify the driver. Our paper presents a rarer case of three-rider motorcycle
http://dx.doi.org/10.1016/j.legalmed.2015.11.006 1344-6223/Crown Copyright Ó 2015 Published by Elsevier Ireland Ltd. All rights reserved.
S. Liu et al. / Legal Medicine 18 (2016) 20–24
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accident. We study the injury information including the groin injury, the underbelly injury and the perineum injuries in this paper. It turned out that the driver was subjected to the groin injury including the underbelly injury, one of the passengers suffered from the injuries on the perineum, and no such injury was found in the other passenger. We consider that the groin injury has some differences with the perineum injuries and the latter should not always be related to the driver especially in high-speed head-on impacting motorcycle accidents. Besides, the injury on the underbelly area is important to identify the driver. 2. Case presentation In a suburb of Chongqing China, three young men (rider A 19year-old, rider B 19-year-old, rider C 21-year-old) were riding on Chinese type motorcycle with a 125 cc engine (JIANSHE) at midnight. The motorcycle carrying the three riders ran straight to a footpath of a bridge at the speed of 70 km/h and collided with the terminal of the footpath (Fig. 1). All riders were thrown from the motorcycle onto the road after the impact. Rider (A) was thrown to a place which was 3.6 meters away from the impact point (Fig. 1). Rider (A) was seriously injured and consequently taken to a hospital. Rider (B) was thrown to a place which was 19.9 meters away from the impact point (Fig. 1). Rider (B) died on the spot as a result of severe head trauma. Rider (C) was thrown to a place which was 28.0 meters away from the impact point (Fig. 1). Rider (C) also died on the spot because of severe head trauma. At the time of the collision, it was at 23 o’clock with dim ambient light. The motorcycle collided with the terminal of the footpath at an impacting angle of approximately 90°. All riders had been wearing half helmets but none had a driving license. The three riders had not drunk alcohol before the accident. In addition, all riders had no previous history of groin or perineum bruise.
Fig. 2. The deformation of the motorcycle after impact (a) front wheel and front fork of the motorcycle (b) the fuel tank of the motorcycle (c) the slope on the surface of the saddle.
saddle is higher than the front of the saddle (Fig. 2c). The terminal of the footpath had a dent on the impacting side.
3. Results
3.2. External examination of the victim (rider A)
After the accident, the motorcycle was violently deformed and the three riders were seriously injured. The detailed results were shown as below.
The external examination was performed in the hospital three days after the accident. The victim was able to respond although he was not fully conscious. Bruises can be obviously found around his groin area including the underbelly area and his perineum area (Fig. 3).
3.1. The damage of the motorcycle On the motorcycle, the front wheel was broken to pieces (Fig. 2a), the front fork of the motorcycle was bent backwards badly (Fig. 2a), and the fuel tank was crushed severely (Fig. 2b). There is a slope on the surface of the saddle and the tail of the
3.3. External examination of the decedent (rider B) The external examination of rider B was performed 12 h postmortem. The body was 157 cm in length and weighed 59 kg. The
Fig. 1. The scene of the three-rider motorcycle accident.
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Fig. 3. The injuries of the rider A (around the groin area, on the underbelly area and on the perineum area).
autopsy report showed there were fractures in the left occipital-temporal part of his skull. There were contusions of about 0.5 cm 0.8 cm, 0.5 cm 0.5 cm on his left geisoma, 2.5 cm 3.0 cm contusions on his left cheek, and 1.0 cm 2.5 cm contusions on his left tempora. Apart from what have been described above, there were some visible bruises only on the perineum area. No injury can be obviously seen on other groin area including his underbelly area. (Fig. 4) We concluded that rider B was thrown out and died as a result of impacting his left part of head against the road. 3.4. External examination of the decedent (rider C) The external examination of the decedent (C) was performed 12 h post-mortem too. The body was 157 cm in length and weighed 63 kg. The autopsy report showed there were also fractures in the parietal-occipital area of his skull. There were contusions of about 1.8 cm 3.8 cm on his right cheek and 2.5 cm 3.0 cm on his left scapular region. Besides, there was neither injury around his groin area, on his underbelly area nor on his perineum area (Fig. 5). We deduced that rider C was thrown out and died because of impacting his top part of head against the road.
4. Discussion It is always important in traffic accidents to identify the driver from the riders because criminal and civil responsibilities usually fall on the driver. Consequently, in medico-legal judgment, all information relating to the identification of the driver must be carefully considered before making any decision. However, in a three-rider motorcycle accident, it is usually difficult to distinguish the driver from the passengers because all riders are thrown from
Fig. 4. The injuries of rider B (there were visible bruises on his perineum area).
Fig. 5. The injuries of rider C (there was neither injury around his groin area, on his underbelly area nor on his perineum area).
the motorcycle at the time of collision and have few positional dependent injuries [1]. According to previous literatures, in multi-rider motorcycle accidents, riders who receive injuries around the groin area including the perineum area are often regarded as the driver. Thus, only the rider C can be crossed off the suspect list because there was no injury around his groin area, nor on his underbelly area or on his perineum area. As a result, rider A and rider B with the so called injury around the groin area and on the perineum area both have the possibility to be the driver. The confusion emerges here. In order to identify the real driver, the positional information and the corresponding injuries are discussed as below.
4.1. Injuries on perineum area As Henry [6] described, perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. It is a diamond-shaped area on the inferior surface of the trunk that includes the anus and, in females, the vagina. There is a line passing through the central point of the perineum, which is situated about 2.5 cm in front of the center of the anal aperture or, in the male, midway between the anus and the reflection of the skin on to the scrotum. Perineum injury is a characteristic injury around the perineum area of the victim which is known as a fuel tank injury, besides, perineum injury is one of the most useful and important findings on the motorcycle driver [1,3]. So, as a rule, the injuries on the perineum areas were often used to identify the driver in multi-rider motorcycle accidents. However, in the presented case, two riders both got injuries on the perineum areas. Therefore, in order to distinguish the driver from the passengers, the mechanism of the perineum injuries ought to be studied carefully. Generally, in a head-on motorcycle impact, when the motorcycle is stopped the riders can all keep their speed for the reason of
S. Liu et al. / Legal Medicine 18 (2016) 20–24
the inertia. Therefore, during the collision the perineum of the driver will firstly glide on the surface of the saddle and then keep gliding and striking on the fuel tank resulting in the perineum injury [7–11]. For the passenger, in fact, after the motorcycle is stopped he will also glide on the surface of the saddle sometimes even on the surface of the fuel tank for the reason of the inertia leading to the perineum injury consequently. That is to say, in a head-on motorcycle accident, the perineum injury can not only occurs on the driver but also sometimes on the pillion passengers. Hence, in multi-rider motorcycle accidents, the perineum injury cannot be the only characteristic injury to identify the driver during medico-legal judgment. 4.2. Injuries on groin area and underbelly area The groin is the junctional area between the abdomen and the thigh [12] on either side of the pubic bone [13]. The groin areas are located on each side of the body in the folds where the belly joins the legs [13]. During a head-on impact, the driver’s groin area will easily hit and squeeze to the two profile sides of the fuel tank resulting in groin injury. Besides, the underbelly area of the driver will also glide on and squeeze to the upper side of the fuel tank resulting in the underbelly injury which is important in identifying the motorcycle driver in medico-legal judgment. In contrast, the passenger who is sitting behind the driver will usually glide on the saddle sometimes even on the fuel tank and then hit the driver’s buttocks and back. Therefore, under the protection of the driver’s buttocks and back, the passenger can hardly suffer from underbelly injury. The previous reports have concluded that the fuel tank injury also called the groin injury was an evidence of the driver, and the victim with the fuel tank injury was always considered to be the driver [1,3]. We consider that besides the groin and perineum injuries, special and more attentions should be paid to the underbelly injury because it can describe the injury of the driver more precisely and comprehensively. 4.3. Simulation and analysis of the presented case In the presented real case, perineum injury, groin injury and underbelly injury all occurred. In order to analyze the impacting process, a three-rider motorcycle model was established by PcCrash (version 10.1, produced by DSD GmbH Linz, Austria). The first three critical impacting frames were shown as follows: Through the Fig. 6, it can be obviously seen that in the impacting process the perineum area of the driver (rider 1 in Fig. 6) glided on the saddle and could lead to perineum injuries. Besides, in the impacting frame, the driver’s underbelly area rubbed against the fuel tank which would result in the underbelly injury. The whole impacting simulation witnessed that only the underbelly area of the driver could seriously strike to the fuel tank and led to
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underbelly injury. Therefore, underbelly injury is important to identify the driver in multi-rider motorcycle accidents. As for the rider 2 and the rider 3, their perineum areas especially the perineum area of the rider 2 had the chance to glide on the saddle and fuel tank and led to perineum injuries. Because of the different protection effect of their sitting-before rider(s), the perineum injury of rider 2 is always more serious than rider 3. It can be seen clearly from the simulation that during the impacting process the rear part of the motorcycle was lifted by the impact and its inertial force. However, the flying direction of the rider 2 and the rider 3 was forward. At the same time, the rider 2 and the rider 3 were farther away from the fuel tank than the rider 1. So, the underbelly area of rider 2 or rider 3 seldom had the chance to contact with the fuel tank and caused injury. Just as rider 1 in the model in Fig. 6, in the real case, because of the rub and impact with the surfaces of the saddle and the fuel tank, rider A suffered from the perineum injury, the groin injury and the underbelly injury. For rider B in the real case, firstly, when the collision happened, rider B was nipped and restrained at the position between rider A and rider C, therefore rider B could not be launched out immediately. Secondly, for the reason of the inertia and the pushing effect provided by rider C, his perineum area would glide on the saddle even on the fuel tank resulting in the perineum injuries (Fig. 4). In addition, his underbelly area was protected by the driver’s buttocks and back and therefore could hardly contact the fuel tank resulting in unscathed. After the collision the tail of the motorcycle went upward and rider B was subsequently thrown forward and upward by the inertia and the pushing effect from rider C. Eventually, the head of riders B impacted on the ground causing the death. For rider C in the real case, firstly, there was a slope on the surface of the saddle and the tail of the saddle was higher than the front of the saddle (Fig. 2c). Therefore, when the collision happened, under the rotational effect of the whole motorcycle, he was launched out for the inertia unrestrainedly. Furthermore, the other two riders were sitting in front of him acting as two buffer objects. Thus, rider C could only slightly contact the saddle leading to no obvious scraping injury on his groin area nor on his underbelly area or on his perineum area (Fig. 5). After the collision, for the same kinematics as rider B, riders C was thrown forward and upward by the inertia and finally his head impacted on the ground leading to the death. To sum up, in the presented real three-rider motorcycle accident, rider A who received the underbelly injury must be the driver and the other two riders must be the passengers which turned out to be consistent to the inquiring records of rider A in the end.
5. Conclusions It is important and necessary to identify the driver in multi-rider motorcycle accidents for the medico-legal judgment because criminal and civil responsibilities usually fall on the driver.
Fig. 6. The three critical impacting frames in Pc-crash simulation.
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The driver identification in motorcycle accidents often rely on the fuel tank injuries. During the identification, the perineum injury sometimes got quite confused with the groin injury and was often wrongly reckoned as a characteristic injury of the driver. This paper shows the perineum injuries can also occur in the pillion rider caused by the friction between the perineum and the surface of the saddle even including the surface of the fuel tank. Besides, the underbelly injury which was discussed in this paper can usually occur only in the driver but hardly in the pillion rider. We consider that the perineum injury has some differences with the groin injury. The perineum injuries should not always be related to the driver especially in high-speed head-on impacting motorcycle accident because it can also be caused by the saddle or even the fuel tank in passengers. Besides, the injury on the underbelly area which is important to identify the driver should be the characteristic injury of a driver. In a multi-rider motorcycle accident, it may possibly be suggested that the rider who suffered from the groin injury including the underbelly injury should potentially be the driver, nevertheless, the rider who only received the perineum injury can sometimes be the passenger.
Conflict of interest None to declare. Acknowledgments This paper was supported by the National Natural Science Foundation of China (31200709, 31170908, 31271006), the Natural Science Foundation of Chongqing of China (CSTC.2011jjA10022), the National Science & Technology Pillar Program of China (2014BAG01B05) and the Special Fund of Chongqing Key Laboratory (CSTC).
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.legalmed.2015. 11.006. References [1] H. Shiono, A. Akane, K. Matsubara, K. Tanabe, S. Takahashi, Identification of the driver in two-rider motorcycle accidents. Inguinal contusion–laceration as an indication of the driver, Am. J. Forensic Med. Pathol. 11 (3) (1990) 190–192. [2] X.Y. Valerie, Y.X. Jolene, Z.C. Zhang, L.T. Teo, Comparison of severity and pattern of injuries between motorcycle riders and their pillions: a matched study, Injury, Int. J. Care Injured 45 (2014) 333–337. [3] K. Kurihara, N. Kuroda, T. Murai, J. Yanagida, Injuries of motorcycle riders. (1) Fuel tank injury, Res. Pract. Forens. Med. 31 (1988) 275–279 (Japanese with English abstract). [4] H. Zhao, R. Chen, G. Deng, et al., Comparison of injuries sustained by drivers and pillion passengers in fatal head-on motorcycle collision accidents, Forensic Sci. Int. 207 (2011) 188–192. [5] Y. Ihama, F. Chiaki, T. Miyazaki, A two-rider motorcycle accident involving injuries around groin area in both the driver and the passenger, Leg. Med. 9 (2007) 274–277. [6] G. Henry, Anatomy of the Human Body, 20th ed., LEA & FEBIGER, Philadelphia, 1918. New York: BARTLEBY.COM, 2000. [7] H.N. Tsai, W.J. Wu, S.P. Huang, et al., Bilateral traumatic testicular dislocation – a case report, Kaohsiung J. Med. Sci. 18 (2) (2002) 95–98. [8] W. Kochakarn, V. Choonhaklai, P. Hotrapawanond, V. Muangman, Traumatic testicular dislocation a review of 36 cases, J. Med. Assoc. Thai. 83 (2) (2000) 208–212. [9] P.K. Tan, Y.M. Lee, Traumatic dislocation of the testes, Ann. Acad. Med. Singapore 27 (2) (1998) 269–271. [10] S.F. Ko, S.H. Ng, Y.L. Wan, et al., Testicular dislocation: an uncommon and easily overlooked complication of blunt abdominal trauma, Ann. Emerg. Med. 43 (3) (2004) 371–375. [11] F.J. Goulding, Traumatic dislocation of the testis: addition of two cases with a changing etiology, J. Trauma 16 (12) (1976) 1000–1002. [12] Dorland’s Illustrated Medical Dictionary, 32nd ed., Elsevier Saunders, Philadelphia, 2011. [13] WebMB.com (internet), Groin problems and injuries, Available from:, (cited 11.08.2015).
Contents lists available at ScienceDirect
Legal Medicine journal homepage: www.elsevier.com/locate/legalmed
Case Report
Underbelly injury based identification of the driver in a three-rider motorcycle accident Shengxiong Liu a,c, Zhiyong Yin b,c,⇑, Sen Su b,c, Kui Li b,c a
Department of Biomedical Engineering, School of Pharmacy & Bioengineering, Chongqing University of Technology, Chongqing 400054, China Department 4, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China c Chongqing Bayi Judicial Identification Center for Traffic Accident, Chongqing 400042, China b
a r t i c l e
i n f o
Article history: Received 25 October 2015 Received in revised form 18 November 2015 Accepted 23 November 2015 Available online 24 November 2015 Keywords: Motorcycle accident Driver identification Groin injury Perineum injury Underbelly injury
a b s t r a c t This paper presents a three-rider motorcycle accident which took place in a suburb of Chongqing China. In the accident, the motorcycle impacted the terminal of a bridge footpath and led to two riders died and one rider injured. After the accident, one rider received injuries around the groin area including the underbelly area and the perineum area. Another rider suffered from injuries only on the perineum areas. In medico-legal judgments, injuries around the groin area also called groin injuries in victims of motorcycle accidents are usually regarded as ‘‘fuel tank injuries” which are commonly found in drivers. But, the injuries around the groin area are sometimes confused with the perineum injuries. Therefore, the perineum injuries are often wrongly reckoned as the ‘‘fuel tank injuries” and used to identify the drivers too. Actually, passengers can sometimes suffer from perineum injuries in many head-on impacting motorcycle accidents. It is of vital matters to understand the differences between groin injuries and perineum injuries so that the real driver who should be responsible for the accident can be recognized. In this paper, the three-rider motorcycle accident was presented and the injury information of the three riders was studied in order to distinguish the real driver from the riders. We consider that the groin injury has some differences with the perineum injury and the latter should not always be related to the driver especially in high-speed head-on impacting motorcycle accidents. In addition, the injury on underbelly areas is important to identify the driver. Crown Copyright Ó 2015 Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction In two-rider or three-rider motorcycle accidents, it is difficult to distinguish the driver from the passengers. However, being able to do so is important for medico-legal judgment [1]. The difficulty in the driver’s identification is that all riders are usually thrown from the vehicle and have few characteristic injuries for each seated location. Valerie et al. reported that there is no statistically significant difference in the severity of injuries between motorcycle riders and pillions of matched pairs [2]. In fact, Injury around the groin area of the victim, known as ‘‘fuel tank injury” is one of the few characteristic findings [3]. But, the injuries around the groin area are often confused with the perineum injuries. According to previous reports, injuries around the groin area including the perineum area, known as fuel tank injuries, were always related to the driver but never to the passengers [1,3,4]. In 2007, Ihama et al. [5] ⇑ Corresponding author at: Department 4, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China. E-mail address: [email protected] (Z. Yin).
presented a rare case of a two-rider motorcycle accident in which the driver suffered from groin injury and the passenger met with the injuries on his perineum area. And the authors made much effort and successfully identify the driver through the traumatic testicular dislocation [5]. For a motorcycle, the surface of the fuel tank is always obliquely upward and forms an obtuse angle with the surface of the saddle. The ‘‘fuel tank injury” usually appears in relatively high-speed head-on motorcycle impacts. During this kind of impact, the motorcycle can fiercely be stopped by the external obstacle. However, because of the powerful inertia, the riders will maintain their initial speeds and continue to move forward with their straddle postures gliding sharply along the surface of the saddle and then strike heavily on the surface of the fuel tank. Consequently, the groin area of the driver who sits nearest to the fuel tank will be injured with high probability by the upper and bilateral surfaces of the fuel tank resulting in ‘‘fuel tank injuries”. In a real two-rider motorcycle accident, it is really difficult to find the injury differences between the riders and then identify the driver. Our paper presents a rarer case of three-rider motorcycle
http://dx.doi.org/10.1016/j.legalmed.2015.11.006 1344-6223/Crown Copyright Ó 2015 Published by Elsevier Ireland Ltd. All rights reserved.
S. Liu et al. / Legal Medicine 18 (2016) 20–24
21
accident. We study the injury information including the groin injury, the underbelly injury and the perineum injuries in this paper. It turned out that the driver was subjected to the groin injury including the underbelly injury, one of the passengers suffered from the injuries on the perineum, and no such injury was found in the other passenger. We consider that the groin injury has some differences with the perineum injuries and the latter should not always be related to the driver especially in high-speed head-on impacting motorcycle accidents. Besides, the injury on the underbelly area is important to identify the driver. 2. Case presentation In a suburb of Chongqing China, three young men (rider A 19year-old, rider B 19-year-old, rider C 21-year-old) were riding on Chinese type motorcycle with a 125 cc engine (JIANSHE) at midnight. The motorcycle carrying the three riders ran straight to a footpath of a bridge at the speed of 70 km/h and collided with the terminal of the footpath (Fig. 1). All riders were thrown from the motorcycle onto the road after the impact. Rider (A) was thrown to a place which was 3.6 meters away from the impact point (Fig. 1). Rider (A) was seriously injured and consequently taken to a hospital. Rider (B) was thrown to a place which was 19.9 meters away from the impact point (Fig. 1). Rider (B) died on the spot as a result of severe head trauma. Rider (C) was thrown to a place which was 28.0 meters away from the impact point (Fig. 1). Rider (C) also died on the spot because of severe head trauma. At the time of the collision, it was at 23 o’clock with dim ambient light. The motorcycle collided with the terminal of the footpath at an impacting angle of approximately 90°. All riders had been wearing half helmets but none had a driving license. The three riders had not drunk alcohol before the accident. In addition, all riders had no previous history of groin or perineum bruise.
Fig. 2. The deformation of the motorcycle after impact (a) front wheel and front fork of the motorcycle (b) the fuel tank of the motorcycle (c) the slope on the surface of the saddle.
saddle is higher than the front of the saddle (Fig. 2c). The terminal of the footpath had a dent on the impacting side.
3. Results
3.2. External examination of the victim (rider A)
After the accident, the motorcycle was violently deformed and the three riders were seriously injured. The detailed results were shown as below.
The external examination was performed in the hospital three days after the accident. The victim was able to respond although he was not fully conscious. Bruises can be obviously found around his groin area including the underbelly area and his perineum area (Fig. 3).
3.1. The damage of the motorcycle On the motorcycle, the front wheel was broken to pieces (Fig. 2a), the front fork of the motorcycle was bent backwards badly (Fig. 2a), and the fuel tank was crushed severely (Fig. 2b). There is a slope on the surface of the saddle and the tail of the
3.3. External examination of the decedent (rider B) The external examination of rider B was performed 12 h postmortem. The body was 157 cm in length and weighed 59 kg. The
Fig. 1. The scene of the three-rider motorcycle accident.
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Fig. 3. The injuries of the rider A (around the groin area, on the underbelly area and on the perineum area).
autopsy report showed there were fractures in the left occipital-temporal part of his skull. There were contusions of about 0.5 cm 0.8 cm, 0.5 cm 0.5 cm on his left geisoma, 2.5 cm 3.0 cm contusions on his left cheek, and 1.0 cm 2.5 cm contusions on his left tempora. Apart from what have been described above, there were some visible bruises only on the perineum area. No injury can be obviously seen on other groin area including his underbelly area. (Fig. 4) We concluded that rider B was thrown out and died as a result of impacting his left part of head against the road. 3.4. External examination of the decedent (rider C) The external examination of the decedent (C) was performed 12 h post-mortem too. The body was 157 cm in length and weighed 63 kg. The autopsy report showed there were also fractures in the parietal-occipital area of his skull. There were contusions of about 1.8 cm 3.8 cm on his right cheek and 2.5 cm 3.0 cm on his left scapular region. Besides, there was neither injury around his groin area, on his underbelly area nor on his perineum area (Fig. 5). We deduced that rider C was thrown out and died because of impacting his top part of head against the road.
4. Discussion It is always important in traffic accidents to identify the driver from the riders because criminal and civil responsibilities usually fall on the driver. Consequently, in medico-legal judgment, all information relating to the identification of the driver must be carefully considered before making any decision. However, in a three-rider motorcycle accident, it is usually difficult to distinguish the driver from the passengers because all riders are thrown from
Fig. 4. The injuries of rider B (there were visible bruises on his perineum area).
Fig. 5. The injuries of rider C (there was neither injury around his groin area, on his underbelly area nor on his perineum area).
the motorcycle at the time of collision and have few positional dependent injuries [1]. According to previous literatures, in multi-rider motorcycle accidents, riders who receive injuries around the groin area including the perineum area are often regarded as the driver. Thus, only the rider C can be crossed off the suspect list because there was no injury around his groin area, nor on his underbelly area or on his perineum area. As a result, rider A and rider B with the so called injury around the groin area and on the perineum area both have the possibility to be the driver. The confusion emerges here. In order to identify the real driver, the positional information and the corresponding injuries are discussed as below.
4.1. Injuries on perineum area As Henry [6] described, perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. It is a diamond-shaped area on the inferior surface of the trunk that includes the anus and, in females, the vagina. There is a line passing through the central point of the perineum, which is situated about 2.5 cm in front of the center of the anal aperture or, in the male, midway between the anus and the reflection of the skin on to the scrotum. Perineum injury is a characteristic injury around the perineum area of the victim which is known as a fuel tank injury, besides, perineum injury is one of the most useful and important findings on the motorcycle driver [1,3]. So, as a rule, the injuries on the perineum areas were often used to identify the driver in multi-rider motorcycle accidents. However, in the presented case, two riders both got injuries on the perineum areas. Therefore, in order to distinguish the driver from the passengers, the mechanism of the perineum injuries ought to be studied carefully. Generally, in a head-on motorcycle impact, when the motorcycle is stopped the riders can all keep their speed for the reason of
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the inertia. Therefore, during the collision the perineum of the driver will firstly glide on the surface of the saddle and then keep gliding and striking on the fuel tank resulting in the perineum injury [7–11]. For the passenger, in fact, after the motorcycle is stopped he will also glide on the surface of the saddle sometimes even on the surface of the fuel tank for the reason of the inertia leading to the perineum injury consequently. That is to say, in a head-on motorcycle accident, the perineum injury can not only occurs on the driver but also sometimes on the pillion passengers. Hence, in multi-rider motorcycle accidents, the perineum injury cannot be the only characteristic injury to identify the driver during medico-legal judgment. 4.2. Injuries on groin area and underbelly area The groin is the junctional area between the abdomen and the thigh [12] on either side of the pubic bone [13]. The groin areas are located on each side of the body in the folds where the belly joins the legs [13]. During a head-on impact, the driver’s groin area will easily hit and squeeze to the two profile sides of the fuel tank resulting in groin injury. Besides, the underbelly area of the driver will also glide on and squeeze to the upper side of the fuel tank resulting in the underbelly injury which is important in identifying the motorcycle driver in medico-legal judgment. In contrast, the passenger who is sitting behind the driver will usually glide on the saddle sometimes even on the fuel tank and then hit the driver’s buttocks and back. Therefore, under the protection of the driver’s buttocks and back, the passenger can hardly suffer from underbelly injury. The previous reports have concluded that the fuel tank injury also called the groin injury was an evidence of the driver, and the victim with the fuel tank injury was always considered to be the driver [1,3]. We consider that besides the groin and perineum injuries, special and more attentions should be paid to the underbelly injury because it can describe the injury of the driver more precisely and comprehensively. 4.3. Simulation and analysis of the presented case In the presented real case, perineum injury, groin injury and underbelly injury all occurred. In order to analyze the impacting process, a three-rider motorcycle model was established by PcCrash (version 10.1, produced by DSD GmbH Linz, Austria). The first three critical impacting frames were shown as follows: Through the Fig. 6, it can be obviously seen that in the impacting process the perineum area of the driver (rider 1 in Fig. 6) glided on the saddle and could lead to perineum injuries. Besides, in the impacting frame, the driver’s underbelly area rubbed against the fuel tank which would result in the underbelly injury. The whole impacting simulation witnessed that only the underbelly area of the driver could seriously strike to the fuel tank and led to
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underbelly injury. Therefore, underbelly injury is important to identify the driver in multi-rider motorcycle accidents. As for the rider 2 and the rider 3, their perineum areas especially the perineum area of the rider 2 had the chance to glide on the saddle and fuel tank and led to perineum injuries. Because of the different protection effect of their sitting-before rider(s), the perineum injury of rider 2 is always more serious than rider 3. It can be seen clearly from the simulation that during the impacting process the rear part of the motorcycle was lifted by the impact and its inertial force. However, the flying direction of the rider 2 and the rider 3 was forward. At the same time, the rider 2 and the rider 3 were farther away from the fuel tank than the rider 1. So, the underbelly area of rider 2 or rider 3 seldom had the chance to contact with the fuel tank and caused injury. Just as rider 1 in the model in Fig. 6, in the real case, because of the rub and impact with the surfaces of the saddle and the fuel tank, rider A suffered from the perineum injury, the groin injury and the underbelly injury. For rider B in the real case, firstly, when the collision happened, rider B was nipped and restrained at the position between rider A and rider C, therefore rider B could not be launched out immediately. Secondly, for the reason of the inertia and the pushing effect provided by rider C, his perineum area would glide on the saddle even on the fuel tank resulting in the perineum injuries (Fig. 4). In addition, his underbelly area was protected by the driver’s buttocks and back and therefore could hardly contact the fuel tank resulting in unscathed. After the collision the tail of the motorcycle went upward and rider B was subsequently thrown forward and upward by the inertia and the pushing effect from rider C. Eventually, the head of riders B impacted on the ground causing the death. For rider C in the real case, firstly, there was a slope on the surface of the saddle and the tail of the saddle was higher than the front of the saddle (Fig. 2c). Therefore, when the collision happened, under the rotational effect of the whole motorcycle, he was launched out for the inertia unrestrainedly. Furthermore, the other two riders were sitting in front of him acting as two buffer objects. Thus, rider C could only slightly contact the saddle leading to no obvious scraping injury on his groin area nor on his underbelly area or on his perineum area (Fig. 5). After the collision, for the same kinematics as rider B, riders C was thrown forward and upward by the inertia and finally his head impacted on the ground leading to the death. To sum up, in the presented real three-rider motorcycle accident, rider A who received the underbelly injury must be the driver and the other two riders must be the passengers which turned out to be consistent to the inquiring records of rider A in the end.
5. Conclusions It is important and necessary to identify the driver in multi-rider motorcycle accidents for the medico-legal judgment because criminal and civil responsibilities usually fall on the driver.
Fig. 6. The three critical impacting frames in Pc-crash simulation.
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The driver identification in motorcycle accidents often rely on the fuel tank injuries. During the identification, the perineum injury sometimes got quite confused with the groin injury and was often wrongly reckoned as a characteristic injury of the driver. This paper shows the perineum injuries can also occur in the pillion rider caused by the friction between the perineum and the surface of the saddle even including the surface of the fuel tank. Besides, the underbelly injury which was discussed in this paper can usually occur only in the driver but hardly in the pillion rider. We consider that the perineum injury has some differences with the groin injury. The perineum injuries should not always be related to the driver especially in high-speed head-on impacting motorcycle accident because it can also be caused by the saddle or even the fuel tank in passengers. Besides, the injury on the underbelly area which is important to identify the driver should be the characteristic injury of a driver. In a multi-rider motorcycle accident, it may possibly be suggested that the rider who suffered from the groin injury including the underbelly injury should potentially be the driver, nevertheless, the rider who only received the perineum injury can sometimes be the passenger.
Conflict of interest None to declare. Acknowledgments This paper was supported by the National Natural Science Foundation of China (31200709, 31170908, 31271006), the Natural Science Foundation of Chongqing of China (CSTC.2011jjA10022), the National Science & Technology Pillar Program of China (2014BAG01B05) and the Special Fund of Chongqing Key Laboratory (CSTC).
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