With a sudden extension of the neck, the arms abduct and move upward and the arm forms a 'C', this is seen in?

Appeared in: DSSSB - 29 August 2019 (Shift-2)

Explanation

The Moro reflex, or startle reflex, is an involuntary response in infants to a sudden loss of support or a loud noise.
The question describes the first phase of the reflex, where the arms spread out (abduction) and extend, and the hands open with fingers forming a 'C' shape.
This is followed by a second phase where the arms are brought back in towards the body (adduction) as if in an embrace.
This reflex is a key indicator of normal neurological function in newborns and typically fades by 4-6 months.

Option A: The Babinski reflex involves the foot, not the arms. It is elicited by stroking the sole of the foot.
Option B: The Plantar reflex, or toe grasp reflex, also involves the foot. It is a grasping motion of the toes in response to pressure.
Option C: The Gallant reflex, or trunk incurvation reflex, involves the trunk and hips, not the arms in a 'C' shape.

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 description as background academic context rather than a clinical decision trigger.
Assessing primitive reflexes is a fundamental part of the newborn neurological examination to evaluate the maturity and integrity of the central nervous system.
An absent or asymmetrical Moro reflex can indicate potential problems such as a brachial plexus injury (e.g., Erb's palsy), a fractured clavicle, or central nervous system depression.
Persistence of the Moro reflex beyond 6 months can be a red flag for underlying neurological disorders, such as cerebral palsy, and warrants further investigation.

How to Approach the Question

First, read the question carefully and identify the key actions described: 'sudden extension of the neck,' 'arms abduct and move upward,' and 'arm forms a C'.
Recognize that these are components of a specific infant reflex.
Systematically review the options provided, which are all types of reflexes.
Recall or deduce the stimulus and response for each reflex listed.
Match the described response (arm abduction, 'C' shape) to the correct reflex. The Babinski and Plantar reflexes involve the feet, and the Gallant reflex involves the trunk, leaving the Moro reflex as the only one that matches the arm movements described.

Concept Tested & Keywords

Concept Tested: Identification of neonatal primitive reflexes based on description.
Stem keywords: sudden extension of the neck, arms abduct, move upward, arm forms a 'C'
Lead-in keywords: this is seen in
Negative lead-in flag: false

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E6 Medicine Macleod Clinical Examination 15e p. 350-352

E6 Anatomy Grays 43e Vol 1 Part 2 p. 97-99

E6 Medicine Harrison 22e Part 2 p. 1285-1287

Practise the full DSSSB - 29 August 2019 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.