Shaken baby syndrome (abusive head trauma) is characterised by the triad of retinal haemorrhages, subdural haematoma, and encephalopathy in the absence of external skull injury. The biomechanical mechanism responsible for the subdural haematoma in shaking alone (without impact) is:

• A Rotational acceleration-deceleration forces stretching and tearing bridging veins between the cerebral cortex and dural sinuses ✓
• B Linear acceleration causing contre-coup contusion of the frontal lobes
• C Compressive skull deformation transmitting force to the brain surface
• D Cerebral arterial vasospasm following acute hypertension from crying

Explanation

In abusive head trauma from shaking, the angular (rotational) acceleration-deceleration applied to the head creates shear forces across the brain-dura interface. Bridging veins (cortical veins traversing the subdural space to drain into dural sinuses) are stretched and torn by this rotational movement, causing bilateral or unilateral acute subdural haematoma. The infant brain is particularly vulnerable due to large head-to-body ratio, underdeveloped neck muscles, and wider subdural space with longer bridging veins. Linear impact produces contre-coup; compressive skull deformation does not produce isolated subdural haematoma without fracture.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

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Written and medically reviewed by the StethoPrep medical team.