The reflex action of the toes are indicative of abnormalities in the motor control pathways leading from cere… - ESIC Nursing Officer - 2019 (Shift-2)

ESIC Nursing Officer - 2019 (Shift-2)

Applied Physiology

Easy

Appeared in: ESIC Nursing Officer - 2019 (Shift-2)

Explanation

The Babinski reflex is elicited by stroking the sole of the foot to check for abnormalities in the motor pathways originating from the cerebral cortex.
A positive Babinski sign in an adult involves the big toe extending upward (dorsiflexion) and the other toes fanning out.
This abnormal response specifically indicates a lesion or damage to the upper motor neurons within the corticospinal tract.
While this response is abnormal in adults, it is a normal finding in infants up to 1-2 years old due to the immaturity of their nervous system.

Option B: The Patellar reflex, or knee-jerk reflex, is a deep tendon reflex that assesses the integrity of the spinal nerves at the L3-L4 level. It tests the peripheral nervous system and spinal reflex arc, not the motor pathways from the cerebral cortex.
Option C: The Achilles reflex, or ankle-jerk reflex, is another deep tendon reflex. It assesses the integrity of the S1-S2 spinal nerves. Like the patellar reflex, it evaluates a spinal reflex arc, not the corticospinal tract.
Option D: The Romberg test is not a reflex but a test for balance. It primarily assesses proprioception (the sense of body position), which is a function of the dorsal columns of the spinal cord and the vestibular system. A positive Romberg test indicates a sensory problem, not a motor pathway abnormality from the cortex.

Visual 1: Diagram - A flowchart showing the steps to perform a Babinski reflex test and illustrating the difference between a normal (flexor) and abnormal (extensor) response.
Visual 2: Infographic - A comparison table highlighting the key differences between Upper Motor Neuron (UMN) signs (e.g., Babinski, spasticity, hyperreflexia) and Lower Motor Neuron (LMN) signs (e.g., muscle atrophy, fasciculations, hyporeflexia).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Neurological assessment of motor pathways and reflexes as background academic context rather than a clinical decision trigger.
Nurses frequently perform neurological assessments, including the plantar reflex, on patients with conditions like stroke, head injury, spinal cord injury, or multiple sclerosis to monitor for changes in neurological status.
A change from a normal (negative) to an abnormal (positive) Babinski sign is a critical finding that must be documented and immediately reported to the physician, as it may indicate worsening neurological function.
What if? If a patient with a known spinal cord injury at T10 has a positive Babinski sign, it is an expected finding consistent with the UMN lesion. However, if a patient admitted for a headache suddenly develops a positive Babinski sign, it becomes an urgent finding suggesting a new, acute brain lesion like a stroke or bleed.

How to Approach the Question

First, identify the key phrases in the question: 'reflex action of the toes' and 'abnormalities in the motor control pathways leading from cerebral cortex'.
This combination points directly to a test for an upper motor neuron lesion.
Next, review the options. Think about what each test assesses.
Recall that the Babinski reflex is specifically a test of the plantar response to check the integrity of the corticospinal tract.
Eliminate the other options: Patellar and Achilles reflexes are deep tendon (lower motor neuron) reflexes, and the Romberg test assesses balance/sensation, not a motor reflex of the toes.

Concept Tested & Keywords

Concept Tested: Neurological assessment of motor pathways and reflexes.
Stem keywords: reflex action, toes, abnormalities, motor control pathways, cerebral cortex
Lead-in keywords: is
Negative lead-in flag: false

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