REVIEWForensic aspects related to pediatric pathology Medicolegal aspects of pediatric head injuries
Roger W. Byard

Marks Professor of Pathology, University of Adelaide and Chief Forensic Pathologist,
Forensic Science South Australia, Adelaide, Australia(Received for publication on July 28, 2006)(Accepted for publication on September 21, 2006)

Abstract. The pathological examination and assessment of inflicted head injuries in infants and young children are often complicated by the subtle nature of the injuries, the nonspecificity of lesions, and the lack of experimental data that can be used to clarify possibleforces and mechanisms of damage. Opinions often have to be given on a number of issues,
with a paucity of information in the literature and lack of specific individual experience. The
following paper reviews some of the problems that are currently found in the medicolegalevaluation of infants and young children with inflicted craniocerebral trauma and issues
that consequently arise in court. (Keio J Med 55 (4) : 149－ 152, December 2006)
Key words: inflicted injury, death, infancy, medicolegal issues

Introduction

Medicolegal issues

Lethal inflicted injuries in young children are most often due to craniocerebral trauma. Injuries to the abdominal organs are the next most common serious problem.
One of the difficulties in the assessment of significant
head trauma in infants is the non-specificity of the clinical presentation, with infants often arriving to hospital in
an encephalopathic state with minimal signs of external
injuries.1, 2 Infants may be fitting with neurological deficits, or be apneic and lethargic with poor feeding. Raised
intracranial pressure with hydrocephalus may be associated with progressive loss of consciousness.
A common difficulty is the lack of a reliable historyof events leading up to the infant’s collapse, with deliberate falsification of details in an attempt to protect
the perpetrator(s). This has been a significant problem
with studies in the past that have accepted the history as
given by carers, without providing critical analyses ofthe likelihood of the described events being responsible
for the resultant injuries, or independent corroboration of
the carers’ stories.3 Significant and life-threatening injuries are often unexplained, attributed to low level falls, orblamed on a sibling.

The LiteratureThe literature cited on inflicted childhood head injury
contains papers with unclear data. This is a particular
problem with earlier studies, where cases were either
taken from data bases without any indication that thepresenting histories had been accurately obtained and independently verified, or where the carers’ histories wereaccepted without question. This has led to considerable
debate, particularly concerning the likelihood of lethal
craniocerebral trauma resulting from simple low level
falls. In an attempt to provide a correlation of carers’
histories and clinical outcome Chadwick et al analyseda series of 317 cases of children who were brought toemergency centers with carers’ histories of falls.3 Seven
deaths occurred in alleged falls from 4 feet or less, with
only one death in falls from 10 to 45 feet. Given the logical inconsistency of a fall of less than 4 feet being eighttimes more lethal than a fall from a much greater height,
an alternative explanation must be sought. It seems clearthat the mechanism of death was not accurate and that
other forces were involved in the children who died after
the alleged low level falls, with perpetrators giving false

Reprint requests to: Prof. Roger W. Byard, Discipline of Pathology, Level 3 Medical School North Building, The University of Adelaide, Frome Road, Adelaide SA 5005, Australia, Email: byard.roger@saugov.sa.gov.au149

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Byard RW: Pediatric head trauma and medicolegal issues

information in an attempt to disguise their involvementin the deaths. Infants and young children survive simple
falls well and deaths have occurred in witnessed falls
only when the height was greater than three stories.4Experience and Research
Questions are often raised in court concerning theamount of force that may be required to cause either
a particular injury in, or the death of, an infant. Thesequestions are sometimes unanswerable, as each case often has quite idiosyncratic features that may make generalising from experience or the literature difficult. Individual medical experience may be limited and it is difficult
to envisage how prospective studies can be conducted
on infants to assess responses to trauma. Unfortunately
the lack of data on injury forces in infants has led to assertions that significant and potentially life-threateninginjuries may derive from minimal trauma. The suggestions that normal ‘wear and tear’ and handling of infants
and toddlers may cause serious damage can, however, bequestioned by the examination of playgrounds and childcare centers. Toddlers and young children often sustain
impacts with considerable force in falls and collisions inplaygrounds and yet deaths under these circumstances
are exceedingly rare. This suggests that usual wear andtear in normal young children is not lethal.
Experiments using models of infant heads and brains
also require careful interpretation as animals and dolls
are not babies. Animals have quite different anatomical
configurations to human infants and extrapolating fromthe forces required to cause (or not cause) certain injuries in a rat or sheep model to a human infant may not be
possible. Mechanical models also suffer from problems,
as it is difficult if not impossible to replicate the complex nature of the human infant brain, with anatomical
features including different tissue densities, nerve fibre
tracts and meningeal coverings, chemical responses toneurotransmitters and autonomic changes resulting invariable blood flow and changing tissue permeability.
Mechanical models may also oversimplify the trajectorythat an infant head has followed, as shaking does notnecessarily follow a simple anterior and posterior path,with oblique, lateral and circular movements all being
possible. These trajectories may also be combined andinvolve different forces in different directions.2 , 5-9
Anatomical Features
Particular anatomical features of infancy that are notpresent in older children predispose to cerebral injuries. Infant heads are relatively large compared to theirbody mass and are poorly supported by immature neckmuscles. This means that infant heads may move quite
violently if shaking or impact occurs. The bones of thedeveloping skull are thin, fragile and unfused, with asmooth base of skull that does not provide the tethering
effect on the brain that occurs with the better-developed
prominent ridges that separate cranial fossae in older
age groups. Immature myelination of the brain renders it
softer than in older children, and a greater relative volume of cerebrospinal fluid also provides more room formovement. The summation of these features renders theinfant brain more vulnerable to shearing injuries when
an infant is exposed to acceleration or deceleration forces.2 , 10 , 11External examination
Internal injuries may occur in infants without much in
the way of external findings; e.g. infants may be thrownor shaken and sustain lethal head injuries without having
bruises or abrasions. Intracranial hemorrhage, axonal injury and cerebral swelling may occur from shaking, withbruising of the chest being prevented by the interposition of clothing. Throwing or hitting an infant against asurface with a soft covering but a firm to hard base, suchas the padded arm of a sofa, may produce unilateral cerebral hemorrhage and bruising without necessarily causing externally obvious injuries. A problem that may arisein the medical assessment of such infants is the assumption that the absence of external injuries implies that theforces involved in the lethal episode were not great. This,
however, cannot be presumed. Another difficulty arises
when inflicted injury is not suspected because of a lackof external injuries. This may result in significant delaysin the investigation, assessment and management of theinfant and his or her family.1
Cervical injury
Recently it has been proposed that features of shaking
may result from less severe force that has injured theupper cervical spinal cord damaging respiratory control
and causing death from hypoxic ischemic encephalopathy.1 2 , 1 3 Certainly injury to the cervical cord may havedevastating effects and so it is vital to examine the cordin all cases of unexpected infant death. It must be emphasized, however, that retinal hemorrhages, cerebral edema
and subdural hemorrhages in an infant may occur in theabsence of any injury to the upper cervical cord, and thathypoxic ischemic encephalopathy is not a recognised
cause of subdural hemorrhage.14
Terminology
A typical case of inflicted head injury involves an infant either being found dead at home with no relevant
history, or being taken for medical assessment in an unconscious state. Clinical examination may reveal finger-

Keio J Med 2006; 55 (4): 149－ 152

tip bruises of the arms and back, with extensive retinal
hemorrhages on fundoscopy. Radiological investigations
may then show cerebral edema with bilateral thin subdural hemorrhages. At autopsy these findings will be confirmed and neuropathological studies may show symmetrical staining for β-amyloid precursor protein (β-APP).
While some would find these features typical of shaking,others would disagree, and it has been argued that shaking alone cannot be responsible for death, and that impact must also occur.1 5 , 1 6 Certainly impact of an infant
head on a firm surface with a soft covering may causesignificant cerebral injury in the absence of externalbruising. Lack of bruising or skull fracture, symmetry offindings and documented confessions of shaking by perpetrators do add support to shaking being responsible for
infant deaths.1 7 However, it may be extremely difficultin individual cases to try to determine the sequence andnature of the lethal injuries from the findings at postmortem. “Blunt craniocerebral trauma” may be the preferredterm as this clearly indicates that there has been significant injury to the head, while allowing for the complexity of possible contributing injuries. Thus, while shaking
may be favoured, impact may not have been excludedin certain cases. Similarly, asymmetric findings withunilateral scalp bruising and comminuted skull fracturesindicate that an impact injury has occurred, but does notexclude the possibility that shaking may have also beena factor if there are bilateral thin subdural and retinal
hemorrhages present. Impact includes situations where
an infant has been held and slammed into a hard object,or where an infant has been stationary and has been hit
with an object or a fist. The significant issue is that inflicted injury must be suspected when a previously wellinfant is found lifeless with evidence of head trauma andwithout a reasonable explanation.
Problem cases
Sally Clark was an English lawyer who was convictedof the murder of her two sons in 1999. The conviction
was overturned by a Court of Appeal in 2003. Part of theprosecution case was that her second son showed evidence of shaking, however what was initially considered
to be retinal hemorrhage was later found to be normal
retinal vessel congestion, and cerebral lacerations were
ultimately found to be due to post-mortem artefact. The
dangers of too readily using the diagnosis of shaken infant syndrome are exemplified by this case.18 , 19
In addition to misinterpretation of findings, a further
problem that has beset pediatric forensic pathology has
been the variation in quality of autopsies that have beenperformed. Individual pathologists have often exhibited
quite idiosyncratic styles in their autopsy practice in thevery young. For example, cases have occurred where no
histological assessment of the brain and cord has been

151

performed, and sometimes the cranial cavity has not evenbeen opened. Specialised ancillary testing such as radiological and microbiological screening may not have been
done.2 0 Because of the complex nature of many issues
that are raised by infant deaths it is often not possible togo back and clarify mechanisms if appropriate dissections, examinations and tests have not been undertaken.
Audits have confirmed these problems and comments
may be found in the literature that ‘investigations into
the pathology and circumstances of sudden infant deathare often scanty and inexpert’.2 1, 2 2 An appropriate way
to avoid omissions and errors at the time of autopsies isfor pathologists and investigators to follow recognised
national and/or international protocols that provide clear
guidelines for the type of examinations that are required
and the range of tests that are recommended.23 , 24
Another issue which is not restricted to pediatric forensic pathology is the use of ‘unique theories of causation’in the analysis of injuries and in postulating possible
mechanisms. An example would be the proposal that intracranial hemorrhages typical of those found in shaking
could be caused by immunization, something that has
not been supported by research. Problems with expert
evidence have been reviewed by Chadwick and Krous
who have listed a series of issues that may arise in addition to the use of unique theories. These include uniqueor very unusual interpretations of the medical findings,
misquoting of the literature, proposing nonexistent medical findings, making false statements and deliberately
omitting important facts.25
Conclusions
Evaluating inflicted craniocerebral trauma in the very
young is often difficult and involves considerable debate.
Difficulties may arise at all stages of the process due toincomplete investigations, badly recorded or inadequately assessed autopsy findings, and conflicting opinions
on injuries and lesions. Infants have unique anatomical
features that may predispose them to certain forms of
injuries, and the interpretation of such injuries is madeeven more difficult by the lack of controlled studies
involving head injury in infants, and the problems associated with the validity, or not, of non-human models.
Recognition by pathologists of the complexities involvedin such cases and the avoidance of speculative theories
and hypotheses in evolution will, however, assist in theevaluation of these matters.
Acknowledgements: I would like to acknowledge and sincerely thankProfessor Masaki Q. Fujita and Dr Toshiko Sawaguchi for their kind
invitation to present a lecture on this subject at the Meeting of the Keio
Medical Society on June 6, 2006.

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Byard RW: Pediatric head trauma and medicolegal issues

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