Inflicted shaking trauma can cause injury in infants, but exact injury mechanisms remain unclear. Controversy exists, particularly in courts, whether additional causes such as impact are required to produce injuries found in cases of (suspected) shaking. Publication rates of studies on animal and biomechanical models of inflicted head injury by shaking trauma (IHI-ST) in infants continue rising. Dissention on the topic, combined with its legal relevance, makes maintaining an up-to-date, clear and accessible overview of the current knowledge-base on IHI-ST essential. The current work reviews recent (2017–2023) studies using models of IHI-ST, serving as an update to two previously published reviews. A systematic review was conducted in Scopus and PubMed for articles using animal, physical and mathematical models for IHI-ST. Using the PRISMA methodology, two researchers independently screened the publications. Two, five, and ten publications were included on animal, physical, and mathematical models of IHI-ST, respectively. Both animal model studies used rodents. It is unknown to what degree these can accurately represent IHI-ST. Physical models were used mostly to investigate gross head-kinematics during shaking. Most mathematical models were used to study local effects on the eye and the head’s internal structures. All injury thresholds and material properties used were based on scaled adult or animal data. Shaking motions used as inputs for animal, physical and mathematical models were mostly greatly simplified. Future research should focus on using more accurate shaking inputs for models, and on developing or and validating accurate injury thresholds applicable for shaking.

A fracture is a partial or complete disruption of the continuity of bone or cartilage, due to mechanical forces exceeding the strength of the bone or cartilage to withstand these forces.Fractures are common in children. In a large Swedish study, the overall annual incidence of fractures in children was 2.1% (2.6 for boys; 1.7 for girls). Most fractures in children are the result of accidental trauma and conventional radiography (x-rays) is by far the preferred modality to diagnose them. This chapter discusses the anatomy of the bones, types of fractures and the terminology to describe fractures in an unequivocal way. In addition, fractures are discussed in the context of the trauma mechanism, the circumstances under which a fracture occurs and the age of the patient. Any discrepancies between the type of fracture and the alleged trauma mechanism (history as provided by the parents) should arise suspicion of non-accidental injury, where in general the younger the child, the greater the probability of inflicted injuries.

Child abuse, irrespective of the type of child abuse, probably is the most prevalent risk factor for the development of children. Physical abuse is the type of abuse with the highest risk of infliction of injuries. The most injured organ due to physical abuse is the skin, with bruises being the most prevalent cutaneous injury. Other cutaneous injuries such as abrasions, lacerations, burns and scalds can also be seen. Fractures are also regularly found in child abuse. Other injuries, often with serious and lifethreatening consequences are intracranial injuries, and abdominal and thoracic injuries. In this chapter child abuse, trauma and injuries will be defined. Also the cause and manner of injuries will be defined and discussed and some epidemiological data will be given.

Various types of complex biomechanical models have been published in the literature to better understand processes related to inflicted head injury by shaking trauma (IHI-ST) in infants. In this systematic review, a comprehensive overview of these models is provided. A systematic review was performed in MEDLINE and Scopus for articles using physical (e.g. dolls) and mathematical (e.g. computer simulations) biomechanical models for IHI-ST. After deduplication, the studies were independently screened by two researchers using PRISMA methodology and data extracted from the papers is represented in a “7-steps description”, addressing the different processes occurring during IHI-ST. Eleven papers on physical models and 23 papers on mathematical models were included after the selection process. In both categories, some models focus on describing gross head kinematics during IHI-ST events, while others address the behavior of internal head- and eye structures in various levels of detail. In virtually all physical and mathematical models analyzed, injury thresholds are derived from scaled non-infant data. Studies focusing on head kinematics often use injury thresholds derived from impact studies. It remains unclear to what extent these thresholds reflect the failure thresholds of infant biological material. Future research should therefore focus on investigating failure thresholds of infant biological material as well as on possible alternative injury mechanism and alternative injury criteria for IHI-ST.

Inflicted blunt force trauma and/or repetitive acceleration-deceleration trauma in infants can cause brain injury. Yet, the exact pathophysiologic mechanism with its associated thresholds remains unclear. In this systematic review an overview of animal models for shaking trauma and their findings on tissue damage will be provided. A systematic review was performed in MEDLINE and Scopus for articles on the simulation of inflicted head injury in animals. After collection, the studies were independently screened by two researchers for title, abstract, and finally full text and on methodological quality. A total of 12 articles were included after full-text screening. Three articles were based on a single study population of 13 lambs, by one research group. The other 9 articles were separate studies in piglets, all by a single second research group. The lamb articles give some information on tissue damage after inflicted head injury. The piglet studies only provide information on consequences of a single plane rotational movement. Generally, with increasing age and weight, there was a decrease of axonal injury and death. Future studies should focus on every single step in the process of a free movement in all directions, resembling human infant shaking. In part II of this systematic review biomechanical models will be evaluated.