A newborn delivered by forceps exhibits an asymmetrical Moro reflex. This finding is indicative of injury to:

NORCET 7 Prelims -2024

Child Health Nursing (Pediatrics)

Hard

Appeared in: NORCET 7 Prelims -2024

Explanation

The Moro reflex is a primitive startle reflex in which a newborn symmetrically abducts and extends their arms, then adducts and flexes them.
An asymmetrical Moro reflex means that one arm does not move or has a weaker response compared to the other, indicating unilateral weakness or paralysis.
The brachial plexus is the network of nerves originating from spinal roots C5-T1 that provides motor and sensory function to the entire upper limb.
During a difficult delivery, such as one requiring forceps, lateral traction on the head and neck can stretch or injure the brachial plexus.
This injury, known as brachial palsy (e.g., Erb's palsy), results in weakness of the arm muscles, causing the Moro reflex to be absent or diminished on the affected side.

Option A: The femoral plexus innervates the muscles of the anterior thigh. An injury here would affect the newborn's ability to extend the leg at the knee, not the arm movements involved in the Moro reflex.
Option B: The sacral plexus supplies the muscles of the posterior thigh, lower leg, and foot. Injury would manifest as problems with the lower extremities, such as foot drop, not an asymmetrical arm reflex.
Option C: The cervical plexus innervates muscles of the neck and, most importantly, gives rise to the phrenic nerve (C3-C5), which controls the diaphragm. While it can be injured during birth, it does not control the arm movements of the Moro reflex.

Visual 1: Diagram - An anatomical illustration of the brachial plexus, showing the nerve roots (C5, C6, C7, C8, T1) and their distribution into the arm.
Visual 2: Illustration - A comparison showing a newborn with a normal, symmetrical Moro reflex versus a newborn with an asymmetrical Moro reflex, where one arm remains limp.
Visual 3: Photograph - A clinical photograph of a newborn with Erb's palsy, demonstrating the characteristic 'waiter's tip' posture of the affected arm.

Clinical Relevance

Nursing practice connection: Knowing Assessment of neonatal birth injuries helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses are often the first to perform a comprehensive newborn assessment, including checking primitive reflexes. Identifying an asymmetrical Moro reflex is a critical finding that requires prompt reporting and further evaluation.
Early diagnosis of brachial plexus injury allows for the initiation of physical therapy to prevent muscle contractures and promote recovery of function.
Patient education is key. The nurse must explain the finding to the parents, provide emotional support, and teach them how to handle the infant carefully to avoid further injury and how to perform range-of-motion exercises as prescribed.

How to Approach the Question

First, identify the key clinical finding in the question stem: 'asymmetrical Moro reflex'.
Recall the normal Moro reflex, which involves symmetrical movement of both arms.
Understand that 'asymmetrical' implies a problem with one side, specifically one of the upper limbs.
Next, analyze the options provided, which are all nerve plexuses.
Systematically link each plexus to the part of the body it innervates: Femoral and Sacral plexuses supply the lower limbs; the Cervical plexus supplies the neck and diaphragm; the Brachial plexus supplies the upper limbs (arms).
Conclude that an injury causing an asymmetrical arm reflex must involve the nerve supply to the arm. Therefore, the brachial plexus is the correct answer.

Concept Tested & Keywords

Concept Tested: Assessment of neonatal birth injuries
Stem keywords: newborn, forceps, asymmetrical Moro reflex, injury
Lead-in keywords: indicative of
Clinical cues: Forceps delivery suggests a potentially difficult or traumatic birth, increasing the risk for injury.
Clinical cues: Asymmetrical Moro reflex is the key clinical sign pointing to a unilateral upper extremity problem.

Q4L0QEy9G8TjcTMqJ60gED