The normal response to the plantar reflex in an adult is:

Appeared in: AIIMS Delhi NO-2016

Explanation

In an adult, the normal response to stroking the sole of the foot is plantar flexion, which means the toes curl downwards.
This flexion response indicates that the corticospinal tracts, which are part of the central nervous system's upper motor neurons, are intact and functioning correctly.
This normal finding is sometimes referred to as a negative Babinski sign.

Option A: Extension (dorsiflexion) of the great toe is an abnormal finding in adults, known as the Babinski sign.
Option C: The Babinski response refers to the abnormal extension of the great toe. The question asks for the normal response in an adult.
Option D: Only one of the options (Flexion) represents the normal response in an adult, making 'All of the above' incorrect.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Neurological Assessment: Plantar Reflex as background academic context rather than a clinical decision trigger.
The plantar reflex is a fundamental component of the neurological examination, used to assess the integrity of the corticospinal tract.
A positive Babinski sign in an adult is a red flag for an upper motor neuron lesion, prompting further investigation for conditions like stroke, spinal cord injury, multiple sclerosis, or a brain tumor.
What if? If the patient was a 9-month-old infant, an extensor (Babinski) response would be considered a normal finding, reflecting the developmental stage of their nervous system. The persistence of this reflex beyond age 2 can indicate a neurological problem.

How to Approach the Question

First, identify the key components of the question: 'plantar reflex', 'normal response', and 'adult'.
Recall the standard procedure for testing the plantar reflex.
Differentiate between the normal physiological response in an adult versus an infant.
The normal adult response is flexion (downward curling) of the toes.
The abnormal adult response (and normal infant response) is extension (upward movement) of the great toe, known as the Babinski sign.
Evaluate the options: 'Flexion' matches the normal adult response. 'Extension' and 'Babinski response' describe the abnormal response. 'All of the above' is therefore incorrect.

Concept Tested & Keywords

Concept Tested: Neurological Assessment: Plantar Reflex
Stem keywords: plantar reflex, normal response, adult
Lead-in keywords: BEST, MOST RELEVANT CLUE
Clinical cues: The question specifies the patient is an adult, which is a critical factor in determining the normal reflex.

QKRv0KS3eTDoQlfShUXqND

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

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

Practise the full AIIMS Delhi NO-2016

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