Purpose or Case Report: Recognising the skeletal manifestations of inflicted injury (II) in infants and young children is of crucial importance. There are specific fracture patterns that are highly suspicious of II and common differential diagnoses with which radiologists should be familiar.
Methods & Materials: The radiologist’s role is to detect findings suggestive of physical abuse, differentiating from other underlying pathologies/normal variants.

Skeletal survey (SS) can detect occult bony injuries and identify underlying medical conditions predisposing to fracturing (metabolic disorder/skeletal dysplasia). Follow-up imaging (approximately 14 days) improves the sensitivity of initial SS, identifies fractures not previously seen due to interval healing, and can assist in dating injuries.
Results: Specific fracture patterns: in a non-ambulant infant, any fracture may be suspicious for physical abuse if the history is inappropriate. Due attention and consideration should be given to the mechanism of injury including whether the history correlates with the radiological findings.

Classic metaphyseal lesion (CML): in the correct clinical context is almost pathognomonic of II. Shearing mechanism/torsional force across metaphyses result in cumulative microfractures of immature bone that rarely occur during ‘normal’ handling. ‘Bucket handle’ and ‘corner’ fractures are descriptive terms given to CMLs.

Posterior rib fractures have strong correlation with II. Follow-up chest radiography should be performed in all cases of suspected abuse given that rib fractures are more easily identified as healing callus develops.

Long bone fractures in non-ambulant infants are always suspicious of II. Undisplaced hairline tibial spiral fracture in an ambulant child (“toddler’s fracture”, common accidental injury) if present in isolation is not suggestive of physical abuse.

Fractures in unusual locations: Scapula, sternum, spinous process (3 S’s) are uncommon but almost diagnostic of II as significant force (high energy) is required. Whilst uncommon, metacarpal, metatarsal and vertebral fractures are occasionally identified reinforcing the need to perform dedicated imaging of these areas as part of the SS.

Dating fractures: difficult and subjective but there are recognised stages of fracture healing.
Acute long bone, rib arc fractures: no periosteal reaction with/without soft tissue swelling, likely sustained in preceding 14 days, most will heal completely by 3 months.
Healing metaphyseal, costochondral fractures: usually less than four weeks old, heal completely by 4-6 weeks.
Vertebral, skull fractures: cannot be reliably dated; soft tissue (scalp) swelling over skull fracture suggests acute (less than 2 weeks) injury.

Abusive head trauma: unexplained/suspicious head injury requires a full SS to detect occult skeletal injury and vice versa.

Differential diagnoses must be considered before diagnosing II.
Osteogenesis imperfecta: congenital disorders of collagen type 1 production affecting bone and connective tissue. With propensity to fracture, the subtypes and corresponding clinical characteristics are extensive.
Rickets: results from undermineralisation of bone with resultant growth plate abnormalities in vitamin D deficient children, including widening and irregularity of the metaphyses with cupping, flaring and fraying.
Birth trauma: beyond 3 months, any birth related injury should have healed.

What to do:
Radiologists play a key role in the detection of II. Failure to instigate child protection measures may result in an infant being exposed to further (potentially fatal) injury if allowed to remain in an abusive environment. It is best practice for any imaging performed in suspected II to be reported by two different suitable experienced radiologists to minimise errors.
Conclusions: The diagnosis of child abuse is complex, to which imaging plays a large and important role.