Effects of input energy and impactor shape on cranial fracture patterns.

This study documents relationships between input energy, impactor shape, and the formation of fractures in human crania. Parietal impact experiments (n = 12) were performed at 67% higher input energy compared to previously reported experiments. Fracture origins, characteristics, and locations were compared at two input energy levels with three impactor shapes (focal "hammer", flat "brick", and curved "bat").

Investigating reverse butterfly fractures: An experimental approach and application of fractography.

Butterfly fractures are expected to form with the transverse portion on the tension side and the wedge portion on the compression side of a bent bone, however wedges have also been observed in the reverse orientation and are reported to be frequent in concentrated 4-point bending. To investigate how these fractures form, concentrated 4-point bending experiments were performed on nine human femora and documented using high-speed video. Videos showed the wedge portion formed as fracture initiated in tension, branched obliquely, then curved to terminate on the tension face.

Experimental investigation of cranial fracture initiation in blunt human head impacts.

The relationship between the point of blunt impact and the location of cranial fracture initiation continues to be poorly understood. The current study used high-speed video to capture cranial fracture initiation and propagation in impact experiments on twelve unembalmed, intact human cadaver heads. Video footage provided direct evidence that blunt cranial impacts can produce linear fractures initiating peripheral to the impact site.

Assessing Impact Direction in 3-point Bending of Human Femora: Incomplete Butterfly Fractures and Fracture Surfaces

Current literature associates bending failure with butterfly fracture, in which fracture initiates transversely at the tensile surface of a bent bone and branches as it propagates toward the impact surface. The orientation of the resulting wedge fragment is often considered diagnostic of impact direction. However, experimental studies indicate bending does not always produce complete butterfly fractures or produces wedge fragments variably in tension or compression, precluding their use in interpreting directionality.

Classification of Porcine Cranial Fracture Patterns Using a Fracture Printing Interface.

Distinguishing between accidental and abusive head trauma in children can be difficult, as there is a lack of baseline data for pediatric cranial fracture patterns. A porcine head model has recently been developed and utilized in a series of studies to investigate the effects of impact energy level, surface type, and constraint condition on cranial fracture patterns. In the current study, an automated pattern recognition method, or a fracture printing interface (FPI), was developed to classify cranial fracture patterns that were associated with different impact scenarios documented in previous experiments.

The Role of Interface Shape on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model,

The forensic literature suggests that when adolescents fall onto edged and pointed surfaces, depressed fractures can occur at low energy levels. This study documents impact biomechanics and fracture characteristics of infant porcine skulls dropped onto flat, curved, edged, and focal surfaces. Results showed that the energy needed for fracture initiation was nearly four times higher against a flat surface than against the other surfaces.

The Role of Interface on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model.

The role of impact interface characteristics on the biomechanics and patterns of cranial fracture has not been investigated in detail, and especially for the pediatric head. In this study, infant porcine skulls aged 2-19 days were dropped with an energy to cause fracturing onto four surfaces varying in stiffness from a rigid plate to one covered with plush carpeting. Results showed that heads dropped onto the rigid surface produced more extensive cranial fracturing than onto carpeted surfaces.

Human Identification via Lateral Patella Radiographs: A Validation Study.

This research examines the utility of patella outline shape for matching 3D scans of patellae to knee radiographs using elliptical Fourier analysis and subjective methods of human visual comparison of patellae across radiographs for identification purposes. Repeat radiographs were captured of cadaver's knees for visual comparison before patellae were extracted and skeletonized for quantitative comparisons. Quantitative methods provided significant narrowing down of the candidate pool to just a few potential matches (<5% of original sample), while the human analysts showed high capacity for correctly matching radiographs, irrespective of educational level (positive predictive value = 99.

Fracture characteristics of entrapped head impacts versus controlled head drops in infant porcine specimens.

In many forensic cases, the job of forensic pathologists and anthropologists is to determine whether pediatric death is due to an abusive act or an accidental fall. The goal of this study was to compare the cranial fracture patterns generated on the parietal bone of a developing, infant porcine (pig, Sus scrofa) model by a controlled energy head drop onto a plate versus previous data generated by blunt force impact at the same energy onto the head constrained to a plate. The results showed that blunt force impacts on a head constrained to a rigid plate produces more fracture, but the same general pattern, as that for a head dropped onto the plate with the same level of impact energy.

Osteological and molecular identification of Brucellosis in ancient Butrint, Albania.

Ancient skeletal remains can harbor unique information about past civilizations at both the morphological and molecular levels. For instance, a number of diseases manifest in bone, some of which have been confirmed through DNA analysis, verifying their presence in ancient populations. In this study, anthropological analysis of skeletal remains from the ancient Albanian city of Butrint identified individuals with severe circular lytic lesions on their thoracic and lumbar vertebrae.

Fracture patterns on the infant porcine skull following severe blunt impact.

The objective of this study was to document patterns of fracture on infant porcine skulls aged 2-28 days (n = 57) because of a single, high energy blunt impact to the parietal bone with rigid (nondeformable) and compliant (deformable) interfaces. Fracture patterns were mapped using Geographic Information System software. For the same generated impact force, the rigid interface produced more fractures than the compliant interface for all ages.

A radiographic assessment of pediatric fracture healing and time since injury.

Past studies and pediatric bone physiology indicate that younger individuals may heal at a faster rate. Additionally, in adults upper limb fractures heal faster than lower limb fractures; this trend is expected for pediatric fractures. This study aims to evaluate and compare rates of fracture repair in children based on age and skeletal element.

Characteristics and prediction of cranial crush injuries in children.

This study documents four clinical cases of fatal crush injuries to children between 1.5 and 6 years of age with correlations between modeled stress and clinically observed fracture patterns. The clinical case fractures were concentrated in the basicranium, bridged the impact sites, and traversed the middle cranial fossa in the area of the spheno-occipital synchondrosis.

Age-dependent fracture characteristics of rigid and compliant surface impacts on the infant skull--a porcine model.

This study documents skull fracture characteristics on infant porcine specimens under known impact conditions with respect to age and interface. A single impact causing fracture was conducted on the skull of porcine specimens aged 2-28 days (n = 76). Paired rigid and compliant impacts at the same energy were conducted at each specimen age.

Age dependent mechanical properties of the infant porcine parietal bone and a correlation to the human.

An infant less than 18 months of age with a skull fracture has a one in three chance of abuse. Injury biomechanics are often used in the investigation of these cases. In addition to case-based investigations, computer modeling, and test dummies, animal model studies can aid in these investigations.

Skull-photo superimposition and border deaths: identification through exclusion and the failure to exclude.

We report on the application of video skull-photo superimposition as an identification method in a case from Ajo, Arizona in which five individuals died after crossing into southern Arizona from Mexico. Initial analyses at the Pima County Forensic Science Center in Tucson, Arizona determined that the disarticulated skeletal remains represented two adult Hispanic males and three adult Hispanic females. Based on biological profiles, both the males and one of the females were tentatively identified and assigned names.

Identifying Southwest Hispanics using nonmetric traits and the cultural profile.

Due to the increasing number of Southwest Hispanics in the United States, as well as the overwhelming number of foreign nationals that die every year trying to enter the United States along the southern United States border with Mexico, new methods for classifying individuals have been established at the Pima County Office of the Medical Examiner in Tucson, Arizona (PCOME). For each of the past 5 years, the PCOME has investigated a record number of deaths associated with these border crossings. The overwhelming majority of the identified decedents are Mexican Nationals.

The effects of skeletal preparation techniques on DNA from human and non-human bone.

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification.

Symmetrical fracturing of the skull from midline contact gunshot wounds: reconstruction of individual death histories from skeletonized human remains.

This paper reports a bilaterally symmetrical cranio-facial fracture pattern that is observed in self-inflicted, midline gunshot wounds. Five cases of self-inflicted gunshots wounds are presented as follows: two high-powered rifle cases, two shotgun cases, and one handgun case. In all five cases the remains were either decomposing or skeletonized and submitted to forensic anthropologists.

Radiographic human identification using bones of the hand: a validation study.

The 1993 Supreme Court case Daubert v. Merrell-Dow Pharmaceuticals, Inc. underscores the importance of validating forensic science techniques.

Punched with a fist: the etiology of a fatal depressed cranial fracture.

We report a case in which a 33-year-old man was discovered unconscious following a fistfight with another man. Emergency neurosurgical efforts to repair a depressed temporoparietal skull fracture and associated brain injuries were unsuccessful. The forensic anthropologist and pathologist worked in tandem to sort out a complex combination of cranial evidence, including healed antemortem trauma, perimortem blunt force trauma, remote and recent neurosurgical intervention, and the craniotomy cut performed at autopsy.

A fast and safe non-bleaching method for forensic skeletal preparation.

Over the last three decades, forensic anthropologists increasingly have consulted on fleshed human remains cases in which the examination of skeletal elements is critical in answering questions of identification and the circumstances of death. This was certainly the case at the Human Identification Laboratory in Tucson, Arizona. As the caseload increased, it became clear that a method for defleshing human remains was needed in order to expeditiously expose the osseous surfaces for analysis, yet at the same time, preserving the evidentiary nature of the material.