Related Experiment Video

Updated: Aug 12, 2026

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
19:15

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale

Published on: August 25, 2014

Fundamental Limits of Shaking a Baby

Richard J Reimann1

  • 1Physics, Boise State University, 1910 University Drive, Boise, ID, 83725-1570.

Journal of Forensic Sciences
|March 24, 2018
PubMed

Insights

Shaking a baby can cause severe head injuries. Physics calculations show that even a low-level fall generates higher head rotation forces than typically considered safe limits for infants.

Area of Science:

  • Biomechanics
  • Pediatric Injury Prevention
  • Physics

Background:

  • Infant head injuries are a significant concern.
  • Understanding the mechanics of shaking and falls is crucial for prevention.
  • Previous research has not fully quantified the physical forces involved.

Purpose of the Study:

  • To apply basic physics principles to determine the mechanical limits of infant head rotation during shaking.
  • To compare these limits with forces generated during car crashes and low-level falls.
  • To provide a quantitative basis for understanding the risks associated with shaking infants.

Main Methods:

  • Utilized fundamental physics definitions and practical limitations.
  • Applied first-order mathematical modeling to a 6-month-old infant.
  • Calculated angular velocity and angular acceleration limits for head rotation.
  • Compared calculated values with data from simulated low-level falls.

Main Results:

  • Determined a head rotation angular velocity limit of approximately 75 rad/s for infants without impact.
  • Calculated a maximum angular acceleration limit of less than 1600 rad/s² without impact.
  • A low-level fall (0.76 m) generated higher forces (83 rad/s and 13,000 rad/s²) in a worst-case scenario.

Conclusions:

  • Basic physics imposes strict limits on the forces generated by shaking an infant.
  • The forces involved in a seemingly minor fall can exceed the calculated safe limits for infant head rotation.
  • These findings underscore the severe biomechanical risks associated with shaking infants.

Keywords:
abusive head traumaaccelerationangularforceforensic sciencelow-level fallphysicsshaken baby syndromewhiplash

More Related Videos

P50 Sensory Gating in Infants12:55

P50 Sensory Gating in Infants

Published on: December 26, 2013

Quantified Assessment of Infant's Gross Motor Abilities Using a Multisensor Wearable09:24

Quantified Assessment of Infant's Gross Motor Abilities Using a Multisensor Wearable

Published on: May 17, 2024

Related Concept Videos

Rigid Body Equilibrium Problems - I00:49

Rigid Body Equilibrium Problems - I

A rigid body is said to be in static equilibrium when the net force and the net torque acting on the system is equal to zero. To solve for rigid body equilibrium problems, do the following steps.
Rigid Body Equilibrium Problems - II01:21

Rigid Body Equilibrium Problems - II

A rigid body is in static equilibrium when the net force and the net torque acting on the system are equal to zero.
Consider two children sitting on a seesaw, which has negligible mass. The first child has a mass (m1) of 26 kg and sits at point A, which is 1.6 meters (r1) from the pivot point B; the second child has a mass (m2) of 32 kg and sits at point C. How far from the pivot point B should the second child sit (r2) to balance the seesaw?
Oscillations about an Equilibrium Position01:04

Oscillations about an Equilibrium Position

Stability is an important concept in oscillation. If an equilibrium point is stable, a slight disturbance of an object that is initially at the stable equilibrium point will cause the object to oscillate around that point. For an unstable equilibrium point, if the object is disturbed slightly, it will not return to the equilibrium point. There are three conditions for equilibrium points—stable, unstable, and half-stable. A half-stable equilibrium point is also unstable, but is named so because...
Stability of structures01:14

Stability of structures

In mechanical engineering, the stability of systems under various forces is critical for designing durable and efficient structures. One fundamental way to explore these concepts is by analyzing systems like two rods connected at a pivot point, O, with a torsional spring of spring constant k at the pivot point. This system is similar in appearance to a scissor jack used to change tires on a car. In this case, the arms of the linkage (equivalent to the rods in this system) are entirely vertical,...
Attachment01:20

Attachment

Attachment is vital for infant development, as warm social interactions support growth and well-being. In a classic 1958 study by Harry Harlow, the significance of warmth and comfort in forming attachments was examined. Harlow separated newborn monkeys from their mothers and provided two artificial "mothers": one made of cold wire and the other covered in soft cloth. Despite the wire mother offering food, the infant monkeys preferred the comfort of the cloth mother, demonstrating that physical...
Limit Laws I01:25

Limit Laws I

Limit laws provide essential tools for analyzing how functions behave as their input approaches a specific value. These laws are particularly useful when dealing with combinations of functions, provided the individual limits exist. The Sum and Difference Laws state that the limit of the sum or difference of two functions equals the sum or difference of their respective limits:The Product Law asserts that the limit of the product of two functions equals the product of their individual limits:A...