Reflex response to a sudden loss of support felt by an infant as if he is falling is called as?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Child Health Nursing (Pediatrics)

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Explanation

The Moro reflex is specifically triggered by a sudden loss of support or the sensation of falling.
The characteristic response is a two-part movement: first, the arms symmetrically abduct and extend, and the hands open.
This is immediately followed by the arms adducting and flexing back toward the body, often accompanied by crying.
This reflex is a key indicator of neurological integrity in a newborn.

Option A: The Startle reflex is similar to the Moro reflex but is triggered by a different stimulus, typically a loud noise or a sudden bright light, not a loss of support. The physical response is also less pronounced, usually involving flexion of the limbs without the distinct abduction-adduction sequence.
Option B: The Glabellar reflex is elicited by tapping the glabella (the smooth area between the eyebrows). The expected response is blinking. It has no connection to a loss of support or falling.
Option D: The Tonic Neck Reflex, also known as the 'fencing posture,' is triggered when the infant's head is turned to one side while they are lying on their back. The arm and leg on the side the head is facing will extend, while the opposite limbs flex. This is a postural reflex related to head position, not a response to falling.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Identification of neonatal primitive reflexes based on stimulus and response as background academic context rather than a clinical decision trigger.
Assessing primitive reflexes like the Moro is a fundamental part of the newborn physical examination, providing a quick and non-invasive window into the infant's neurological status.
An absent, weak, or asymmetrical Moro reflex is a red flag that requires immediate further investigation. For instance, an asymmetrical response could point to a birth injury like a clavicle fracture or brachial plexus palsy on the non-responsive side.
What if the Moro reflex is still strongly present in a 9-month-old infant? This is abnormal and is called a persistent primitive reflex. It suggests a delay in neurological maturation and can be an early sign of conditions like cerebral palsy, warranting a referral to a pediatric neurologist.

How to Approach the Question

First, identify the core action or stimulus described in the question stem. Here, the key phrase is 'sudden loss of support' or the feeling of 'falling'.
Next, recall the specific triggers for the common primitive reflexes listed in the options.
Match the stimulus from the question to the correct reflex. The sensation of falling is the classic trigger for the Moro reflex.
Differentiate it from similar reflexes. The Startle reflex is triggered by sound/light, and the Tonic Neck reflex is triggered by head turning.
Select the option that directly corresponds to the described stimulus-response pair.

Concept Tested & Keywords

Concept Tested: Identification of neonatal primitive reflexes based on stimulus and response.
Stem keywords: Reflex response, sudden loss of support, infant, falling
Lead-in keywords: is called as
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.
Negative lead-in flag: false

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