A nurse is assessing a 2-day-old newborn's primitive reflexe… | 마이메르시 MyMerci
Maternal Newborn Health
문제

A nurse is assessing a 2-day-old newborn's primitive reflexes. Which finding would indicate a normal Moro reflex?

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).

심화 해설

Core Nursing Explanation Key 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
ReflexStimulusNormal ResponseAge of Disappearance
Moro (Startle)Sudden movement, noise, head dropArms/legs extend & abduct, then flex & adduct4-6 months
RootingStroke cheek/mouthTurns head toward stimulus, opens mouth3-4 months
Palmar GraspPressure on palmFingers flex in a strong grasp4-6 months
Babinski (Plantar)Stroke sole of footBig toe dorsiflexes, other toes fan12-24 months
Tonic Neck (Fencing)Turn head to one side while supineArm/leg on face side extend, opposite limbs flex4-6 months

Side-by-Side Comparison!
ReflexCommon MistakeKey Differentiator
MoroConfusing with simple "startle" or cryingLook for the specific two-phase arm movement pattern (extension then flexion).
RootingConfusing with sucking reflexRooting is the head-turning search for food. Sucking is the rhythmic mouth action once the nipple is found.
Babinski (Infant)Applying adult norms to infantsIn 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 Tips Mnemonic 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.)

임상 시나리오

Nursing Clinical Practice Guide Clinical 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 Flow Procedure 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!"

핵심 개념

마이메르시로 국가고시 완벽 대비

기출문제와 상세 해설을 무료로. 내 약점을 분석하고 진도를 관리하며 더 똑똑하게 공부하세요.

무료로 시작하기

학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요.