Jayaratnam Jayamohan, a consultant paediatric neurosurgeon, said five-month-old Summer Peace, from Dudley, suffered a flexion-extension injury.
Summer was allegedly murdered by her father Philip Peace, who is standing trial at Birmingham Crown Court.
The court was told a flexion-extension injury related to the movement of the head and neck both forwards and backwards.
Mr Jayamohan told prosecutor Mr Andrew Smith QC the traumatic injury could be caused either accidentally or non-accidentally.
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Jurors were also told it was probable Summer had Hypermobility Spectrum Disorder (HSD) which could have made her more fragile.
Mr Jayamohan said the “absolute minimum” of force required for the injuries wasn’t known due to the difference between children, a judge heard.
He added it was “fair and safe” to say a simple extension movement – a backwards motion – was “unlikely” to explain the injuries but was not impossible, the court was told.
Mr Smith QC asked whether defendant Philip Peace’s account over Summer’s injuries – that her head and arms went backwards when he lifted her – explained them.
Mr Jayamohan responded by saying there needed to be “more action” than a simple extension to cause the injuries.
The consultant paediatric neurosurgeon added he would have “difficulty explaining” the injuries unless there was a greater vascular fragility than he understood, jurors were told.
He added his interpretation of the interviews Peace conducted with the police revealed there was not an “extensive movement” described which is likely to cause the injuries, but it wasn’t impossible, jurors heard.
Mr Michael Turner QC, defending Peace, asked the witness whether it was possible for a child who has a slightly bigger head to be more susceptible to the “whiplash-type injuries”.
In response to the question, Mr Jayamohan said it was possible for a bigger head to increase the force of any whiplash event.
He added the “weaker” the neck, the greater risk of these kind of injuries, jurors heard.
Philip Peace, aged 42, of Himley Road in Dudley, denies murder and manslaughter.
The trial continues.