A nurse is assessing a 2-day-old newborn's primitive reflexes. Which finding would indicate a normal Moro reflex?
1The newborn turns the head toward the side when the cheek is stroked
2The newborn extends and abducts the arms, then flexes and adducts them when startled✓ 정답
3The newborn grasps the examiner's finger when the palm is touched
4The newborn extends the leg on the same side when the sole of the foot is stroked
해설
The Moro reflex normally involves arm extension/abduction followed by flexion/adduction when startled. Other options describe rooting (turning head), palmar grasp (grasping finger), and Babinski reflex (leg extension).
Core Nursing ExplanationKey Concept Analysis: This question assesses your knowledge of primitive reflexes in a newborn. Primitive reflexes are involuntary, stereotyped movements present at birth that originate in the brainstem. They are crucial indicators of neurological integrity and typically disappear within the first few months to a year of life as higher brain centers mature. The specific reflex in question is the Moro reflex, also known as the startle reflex.
Answer Rationale: The correct description of a normal Moro reflex is: Key Point! When the newborn is startled (e.g., by a sudden noise, movement, or the "head-drop" maneuver), the infant's initial response is to extend and abduct the arms and legs, open the hands, and often cry. This is followed by a second phase where the infant flexes and adducts the arms and legs back toward the body, as if embracing. This two-phase "extension-abduction then flexion-adduction" pattern is the hallmark of the Moro reflex. Its absence, asymmetry, or persistence beyond 4-6 months of age can indicate neurological problems.
Distractor Analysis:
Watch out for confusion! Option 1 describes the Rooting reflex. When the cheek or corner of the mouth is stroked, the newborn turns the head toward that stimulus to "root" for the nipple. This aids in feeding.
Option 3 describes the Palmar grasp reflex. When pressure is applied to the palm, the newborn's fingers flex in a strong grasp. This reflex is a precursor to voluntary grasping.
Option 4 describes the Babinski reflex (plantar reflex). When the sole of the foot is stroked from heel to toe along the lateral edge, the normal newborn response is dorsiflexion of the big toe and fanning of the other toes. In an adult, this finding would be abnormal and indicate upper motor neuron disease, but in an infant, it is a normal primitive reflex.
Related Concepts: Assessment of primitive reflexes is a standard part of the newborn neurological exam. Other important reflexes include the Tonic neck reflex (fencing posture), Stepping reflex, and Sucking reflex. The disappearance of these reflexes on schedule is as important as their presence at birth.
Concept Summary
Reflex
Stimulus
Normal Response
Age of Disappearance
Moro (Startle)
Sudden movement, noise, head drop
Arms/legs extend & abduct, then flex & adduct
4-6 months
Rooting
Stroke cheek/mouth
Turns head toward stimulus, opens mouth
3-4 months
Palmar Grasp
Pressure on palm
Fingers flex in a strong grasp
4-6 months
Babinski (Plantar)
Stroke sole of foot
Big toe dorsiflexes, other toes fan
12-24 months
Tonic Neck (Fencing)
Turn head to one side while supine
Arm/leg on face side extend, opposite limbs flex
4-6 months
Side-by-Side Comparison!
Reflex
Common Mistake
Key Differentiator
Moro
Confusing with simple "startle" or crying
Look for the specific two-phase arm movement pattern (extension then flexion).
Rooting
Confusing with sucking reflex
Rooting is the head-turning search for food. Sucking is the rhythmic mouth action once the nipple is found.
Babinski (Infant)
Applying adult norms to infants
In infants, toe fanning is Normal. In adults, it's a Pathological sign of corticospinal tract damage.
Anatomy, Physiology & Pharmacology Points
The primitive reflexes are mediated by the brainstem and spinal cord and are present before the cerebral cortex is fully developed. Their integration (disappearance) occurs as the corticospinal tracts myelinate and higher cortical centers gain inhibitory control over these lower-level responses. Persistence of reflexes beyond their expected timeline can signal conditions like cerebral palsy or other neurological impairments.
Memory TipsMnemonic for Moro Reflex: "Moro = More Motion" or "Startle = Spread then Snuggle." Remember the sequence: Startle → Spread (extend/abduct) → Snuggle (flex/adduct).
Quick ID Trick: If the question mentions "arms" and "startled," think Moro. If it mentions "cheek," think Rooting. If it mentions "palm," think Grasp. If it mentions "sole of foot," think Babinski.
High-Frequency NCLEX Topics
Newborn assessment, including primitive reflexes, is a Core topic. The NCLEX often tests your ability to:
1. Identify the correct response for a named reflex.
2. Recognize which reflex is being demonstrated in a scenario.
3. Understand the clinical significance of an absent, asymmetric, or persistent reflex.
4. Differentiate between normal newborn findings and abnormal adult findings (especially Babinski).
Watch Out for Question Variations!
The same concept can be tested in different ways:
Reverse Identification: "The nurse observes a newborn extend and abduct the arms when startled. Which reflex is this?" (Answer: Moro)
Abnormal Finding: "A 9-month-old infant still exhibits a strong Moro reflex. What does this finding suggest?" (Answer: Possible neurological delay)
Priority Action: "A newborn has an absent Moro reflex on one side. What is the nurse's priority action?" (Answer: Notify the healthcare provider/HCP for further neurological evaluation.)
Nursing Clinical Practice GuideClinical Scenario: You are performing a routine assessment on Baby Girl Rodriguez, a 36-hour-old newborn in the well-baby nursery. The mother asks, "Why does she jump like that every time there's a loud noise?" As you prepare to assess the Moro reflex, you explain its purpose and what you're looking for.
Nursing Intervention Strategy:
1. Assessment: Ensure the infant is awake, alert, and lying supine on a firm surface. One common method is to support the infant's head and shoulders slightly off the bed, then allow the head to drop back a few centimeters (the "head-drop" maneuver) while continuing to support it. Never let the head fall freely. Alternatively, you can produce a sudden loud noise near the infant. Observe the bilateral symmetry and completeness of the two-phase arm/leg movement.
2. Nursing Care & Patient Education: Explain to parents that the Moro reflex is a normal sign of a healthy nervous system. Reassure them that the infant's startle responses will lessen as the nervous system matures. Demonstrate safe swaddling techniques, as a snug swaddle can help contain the Moro reflex and prevent the infant from startling themselves awake.
3. Evaluation & Reporting: Document the reflex as "present and symmetric" or note any abnormalities (e.g., "Moro reflex absent on left," "asymmetric Moro noted"). An absent, weak, or asymmetric Moro reflex requires immediate notification of the pediatrician or neonatal nurse practitioner, as it may indicate brachial plexus injury (e.g., Erb's palsy), clavicle fracture, or a more central neurological issue.
Patient Safety and Precautions:
Contraindication/Caution: Do not perform the head-drop maneuver if there is any suspicion of cervical spine injury or in very premature infants with fragile vasculature.
Key Monitoring: Always assess for symmetry. Asymmetry may point to a peripheral nerve injury (like from shoulder dystocia during delivery) rather than a central brain problem.
Nursing Procedure & Medication FlowProcedure for Eliciting the Moro Reflex:
1. Position infant supine on a firm, flat surface.
2. Ensure the infant is in a quiet, alert state.
3. Gently lift the infant's head and shoulders a few inches, supporting the head.
4. Quickly but gently lower the head back a short distance (allowing it to "startle").
5. Observe and Document: Immediate symmetric extension/abduction of arms (fingers spread, legs may extend), followed by flexion/adduction of arms (embracing motion). The infant may cry.
Alternative Method: Strike the mattress beside the infant's head to create a sudden vibration/noise.
A Word from Your Senior Nurse
"Mastering newborn assessments like primitive reflexes is where you truly become the eyes and ears for your tiniest patients. They can't tell you what's wrong, but their reflexes speak volumes about their neurological health. When you see an asymmetric Moro, don't just document it—think critically. Could it be a birth injury? Is there a clavicle fracture you haven't palpated yet? This kind of integrated thinking, connecting your assessment findings to potential pathophysiology, is what makes an excellent pediatric nurse. On the NCLEX, they're testing your ability to make these connections, not just memorize reflex names. So, learn the 'why' behind the reflex—it will stick with you long after the exam!"
Primitive Reflexes — Involuntary, stereotyped movements present at birth that indicate brainstem and spinal cord function. They disappear as the cerebral cortex matures.
Moro Reflex (Startle Reflex) — A primitive reflex elicited by a sudden stimulus, causing the infant to extend and abduct the arms/legs, then flex and adduct them. Absence or asymmetry can indicate neurological issues.
Rooting Reflex — A primitive reflex where stroking the cheek or mouth causes the infant to turn the head toward the stimulus, aiding in finding the nipple for feeding.
Palmar Grasp Reflex — A primitive reflex where pressure on the palm causes the infant's fingers to flex in a strong grasp. It is a precursor to voluntary grasping.
Babinski Reflex (Plantar Reflex) — A normal primitive reflex in infants where stroking the sole of the foot causes dorsiflexion of the big toe and fanning of the others. In adults, this response is abnormal and indicates upper motor neuron disease.