Analysis of histomorphometric variables: Proposal and validation of osteon definitions.

Histological analysis of bone tissue has been used to explore a variety of questions relating to age-at-death, habitual behaviors, health, and nutritional stress. Identification of intact and fragmentary osteons is of key interest to many researchers in these studies, yet the definitions of these features vary between researchers making cross-study comparisons problematic. Furthermore, histological variable definitions are often ambiguous or require subjective classifications by the observer. As a result, and as indicated by previous studies, observer error and misclassification of certain variables, namely intact and fragmentary osteons, can be significant. This study proposes new definitions for intact and fragmentary osteons that are designed to limit observer subjectivity and also explore efficacy of combining osteon types into one variable. A sample of 30 6th rib cross-sections from a modern forensic population was used to test the validity of the proposed definitions. Observations of intact osteon population density (OPD(I)) and fragmentary osteon population density (OPD(F)) were made by three observers for each cross-section. These observations were used to explore the interobserver error associated with the proposed definitions and determine if combining variables into one variable (OPD) mitigates persisting classification difficulties. Results indicate that the proposed definitions significantly reduce interobserver error and misclassification of intact and fragmentary osteons. However, the interobserver error associated with fragmentary osteons is still high. Evaluation of the variables independently indicates that combining variables has potential to reduce the predictive strength of an age estimation model and the ability to interpret age-related bone remodeling.

The first step in an investigation of quantitative ultrasound as a technique for evaluating infant bone strength.

This study's purpose is to evaluate whether bone speed of sound (SOS) data, a parameter of quantitative ultrasound, collected from an infant autopsy sample are comparable to data collected from healthy, living infants. We hypothesize that SOS values obtained from deceased term-born infants will fall within the normal range for healthy, living infants. The study sample consists of 351 deceased infants between the ages of 30 weeks gestation at birth to 1 year postnatal at the time of death receiving autopsies at the Harris County Institute of Forensic Sciences or Texas Children's Hospital in Houston, TX. Various multivariate and univariate statistics were used to examine the relationship between SOS and age, prematurity, and chronic illness. The results of an ANOVA comparing the study sample data to published data from healthy, living infants indicate the SOS data are comparable. Additionally, a MANOVA indicated significant differences in SOS related to prematurity (p = 0.001) and age (p < 0.001). Mean SOS was significantly greater among term-born infants (M = 3065.66, SD =165.05) than premature infants (M = 2969.71, SD =192.72). Age had a significant polynomial (cubic) relationship with SOS for both the premature and term groups (p < 0.001). Results suggest that bone from an infant autopsy sample is an appropriate surrogate to examine the relationship between SOS and determinants of bone strength. Therefore, future research will use this study sample to investigate the relationship between SOS and determinants of bone strength in infants.

The Infant Injury Database: A Tool for the Study of Injury Patterns in Medicolegal Investigations of Child Abuse.

In 2012, the Harris County Institute of Forensic Sciences began prospectively collecting injury data from pediatric autopsies. These data and associated case information from 635 pediatric cases are archived in the Infant Injury Database (IID). This paper introduces the IID to the forensic community and demonstrates its potential utility for child abuse and infant fatality investigations. The database is intended to be a source of evidence-based research for coroners/medical examiners and clinicians in the recognition and diagnosis of child abuse. RR estimates were employed to quantify the relationship between individual autopsy findings to trauma-related and nontrauma-related causes of death. For example, unsurprisingly, the RR of trauma cases with multiple injury types is significantly greater than other causes of death, but the RR results provide a quantitative representation of the relationship. ROC curve modeling of the presence/absence of various injury types performed well at discriminating trauma from other causes of death (AUC = 0.96).

A Novel Method for Removing a Spinal Cord with Attached Cervical Ganglia from a Pediatric Decedent.

A diagnosis of child abuse is dependent on a comprehensive and accurate assessment of injury in the context of a thorough investigation. However, signatures of trauma are often subtle and interpretation can be very difficult. Recently, researchers have refocused their attention from the head to the neck in search of traumatic signatures of abusive head trauma. HCIFS has developed a technique to remove the cervical spinal cord with the ganglia attached that is less destructive and more time and cost efficient than alternative methods previously published. Once removed, the dorsal nerve roots and ganglia are evaluated for the presence of hemorrhage. The authors performed a small pilot study using the novel method to evaluate 20 decedents with a history of blunt force trauma and eight without a traumatic history. Fifteen of the traumatic deaths and two of the nontraumatic deaths were found to have dorsal nerve root and/or ganglia hemorrhage.

The Laryngohyoid Complex in Medicolegal Death Investigations.

The laryngohyoid complex, composed of the hyoid bone and laryngeal cartilages, can be of interest in the autopsy setting, particularly when injuries are observed. Analysis of trauma to this structure can assist in establishing cause and manner of death. In many situations, the forensic anthropologist, with their expertise in analyzing bone and cartilage trauma, can assist in analyzing trauma to this complex. Although researchers have tried to study the relationships between causes of trauma to the osseocartilaginous structure and the observed injury pattern, they have not been successful in identifying unique signatures associated with different causes of trauma. This is because different causes can result in the same or similar injury patterns. In addition, variation due to growth and development or due to remote injury may change the structure's biomechanical response. The goal of this paper is to address issues that a forensic pathologist may encounter when assessing potential trauma to the osseocartilaginous structures of the laryngohyoid complex; in particular, it focuses on anatomical variants and trauma resulting from various causes.

A silver-stain modification of standard histological slide preparation for use in anthropology analyses.

The traditional histology method typically employed by forensic anthropologists involves plastic embedding of undecalcified bone. The embedded sample is then cut by a diamond blade saw and ground to the required thickness of ~50-100 microns using a grinder. There are several limitations to this method: Cement lines may be blurred; depth-of-field artifacts may result from viewing thick sections; and medicolegal offices with limited budgets may not be able to invest in additional equipment or training for this method. A silver nitrate stain modification of the standard histology preparation technique of decalcified bone is presented. The benefits of this technique are that: Cement lines are viewed clearly; no depth-of-field artifacts are present; and because this is a modification of the standard technique used by histology laboratories typically employed by medicolegal offices, no additional equipment or training is required.

A proposed scheme for classifying pediatric rib head fractures using case examples.

Pediatric rib head fractures are typically described as "posterior" or "costovertebral," terms lacking specificity. To resolve this issue, a scheme was developed to describe the location of rib head fractures observed in a pediatric forensic population. The scheme uses three anatomical landmarks, terminus (tip), tubercle, and costovertebral articular surface to divide the rib head into two subregions, costovertebral and costotransverse. Examples of five cases of infants with rib head fractures are presented using this scheme. Forty-eight rib head fractures were observed in these infants with the following frequencies: 56% (three infants) at the terminus; 21% (three infants) in the costovertebral subregion; 21% (one infant) at the costovertebral articular facet; and 2% (one infant) in the costotransverse subregion. Due to the small number of cases assessed, statistical analyses could not be performed; however, the data demonstrate the variation in distribution of pediatric rib head fractures.

Standardized descriptive method for the anthropological evaluation of pediatric skull fractures.

The literature pertaining to pediatric skull fracture is primarily clinically based and thus motivated by the need for effective assessment of both fracture characteristics (type, frequency, location, and mechanics) and context (severity of injury, associated soft tissue damage, and prognosis). From a strictly descriptive standpoint, these schemas employ overlapping levels of detail that confound the nonclinical description of fractures in the forensic context. For this reason, application of these schemas in the forensic anthropological interpretation of skull fractures is inappropriate. We argue that forensic anthropological interpretation of skull fractures requires a standard classification system that reflects fracture morphology alone, and we suggest a three-stepped classification system that conveys increasing detail with each additional step. A retrospective application of the method to a sample of 31 children aged 1 month to 2 years demonstrated its efficacy in the description of pediatric skull fractures.

Manual and automated cardiopulmonary resuscitation (CPR): a comparison of associated injury patterns.

The purpose of this study was to identify and compare patterns of trauma associated with AutoPulse(®) CPR and manual CPR. Finalized autopsy records from 175 decedents brought to the Harris County Institute of Forensic Sciences were reviewed, 87 received manual-only CPR, and 88 received AutoPulse(®) CPR (in combination with manual CPR as per standard protocol). The characteristic pattern observed in manual-only CPR use included a high frequency of anterior rib fractures, sternal fractures, and midline chest abrasions along the sternum. The characteristic pattern observed in AutoPulse(®) CPR use included a high frequency of posterior rib fractures, skin abrasions located along the anterolateral chest and shoulder, vertebral fractures, and a few cases of visceral injuries including liver lacerations, splenic lacerations, and hemoperitoneum. Knowledge of the AutoPulse(®) CPR injury pattern can help forensic pathologists differentiate therapeutic from inflicted injuries and therefore avoid an erroneous assessment of cause and manner of death.

Novel classification system of rib fractures observed in infants.

Rib fractures are considered highly suspicious for nonaccidental injury in the pediatric clinical literature; however, a rib fracture classification system has not been developed. As an aid and impetus for rib fracture research, we developed a concise schema for classifying rib fracture types and fracture location that is applicable to infants. The system defined four fracture types (sternal end, buckle, transverse, and oblique) and four regions of the rib (posterior, posterolateral, anterolateral, and anterior). It was applied to all rib fractures observed during 85 consecutive infant autopsies. Rib fractures were found in 24 (28%) of the cases. A total of 158 rib fractures were identified. The proposed schema was adequate to classify 153 (97%) of the observed fractures. The results indicate that the classification system is sufficiently robust to classify rib fractures typically observed in infants and should be used by researchers investigating infant rib fractures.

Brief communication: the effects of disuse on the mechanical properties of bone: what unloading tells us about the adaptive nature of skeletal tissue.

The intricate link between load environment and skeletal health is exemplified by the severe osteopenia that accompanies prolonged periods of immobilization, frequently referred to as disuse osteoporosis. Investigating the effects disuse has on the structural properties of bone provides a unique opportunity to better understand how mechanical loads influence the adaptation and maintenance of skeletal tissue. Here, we report results from an examination of multiple indicators of bone metabolism (e.g., mean osteon density, mean osteon size, bone mass, and bone area distribution) within the major long bones of individuals with distinct activity level differences. Results are based on a sample comprising two subjects that suffered from long-term quadriplegia and 28 individuals of comparable age that had full limb mobility. Although limited in sample size, our findings suggest bones associated with long-term disuse have lower osteon densities and larger osteon areas compared to individuals of normal mobility, reflecting dramatically lower remodeling rates potentially related to reduced strain levels. Moreover, immobilized skeletal elements demonstrate a reduced percentage of cortical area present resulting from endosteal resorption. Differences between mobility groups in the percentage of cortical area present and bone distribution of all skeletal elements, suggests bone modeling activity is negligible in the unloaded adult skeleton. Additional histomorphometric comparisons reveal potential intraskeletal differences in bone turnover rates suggesting remodeling rates are highest within the humeri and femora. Addition of more immobilized individuals in the future will allow for quantitative statistical analyses and greater consideration of human variation within and between individuals.