Final answer:
Infants and toddlers are at risk for acceleration/deceleration injuries due to their proportionally larger heads and mobile spines, compounded by the presence of fontanels, especially the occipital fontanel.
Step-by-step explanation:
Infants and toddlers are at risk for acceleration/deceleration injuries due to their large heads and mobile spines. Characteristics of newborn infants, such as soft spots in the skull known as fontanels, allow for the head to change shape slightly during birth but also contribute to this vulnerability. The posterior (occipital) fontanel, situated at the back of the head, in combination with their large head size relative to their body, makes young children more susceptible to these types of injuries. Injuries can occur from events like falls or, in more severe cases, from non-accidental trauma such as shaken-baby syndrome, which can cause brain swelling and retinal hemorrhage.
Falls are among the most common causes of head injuries in young children, and accidents involving automobiles can lead to significant impacts to the head. The occurrence of a cranial injury could lead to the various symptoms listed, such as temperature instability, seizures, bulging fontanel, stiff neck, and hemiparesis, all of which are significant health concerns in infants. Additionally, the occipital bone at the base of the skull is particularly at risk of fracture, which can cause serious damage.