Movement of Thumb & Little finger towards each other called?

Appeared in: PGIMER Sangrur NO - 2023

Explanation

Opposition is the specific anatomical term for the movement where the thumb is brought across the palm to touch the tip of another finger.
This movement is unique to humans and some primates, enabling precise grip and fine motor skills.
It is a complex motion involving a combination of flexion and medial rotation at the saddle joint of the thumb (first carpometacarpal joint).
The primary muscles responsible are the opponens pollicis and opponens digiti minimi.

Option B: Abduction is the movement of a body part away from the central line of the body or a limb. For fingers, it means spreading them apart, not bringing the thumb and little finger together.
Option C: Adduction is the opposite of abduction; it is the movement of a body part toward the central line. While it involves bringing digits 'together', it does not describe the specific thumb-to-finger tip action.
Option D: Extension refers to straightening a joint, which increases the angle. This movement is the opposite of bending (flexion) and does not describe the thumb moving across the palm to meet another finger.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomical terminology for movements of the hand and thumb as background academic context rather than a clinical decision trigger.
Assessing a patient's ability to perform opposition is a key part of a neurological examination. Inability to perform this movement can indicate damage to the median nerve, which innervates the thenar muscles responsible for opposition.
This assessment is crucial in conditions like Carpal Tunnel Syndrome, after wrist injuries, or during rehabilitation for stroke patients to gauge recovery of fine motor skills.
What if? If a patient could move their thumb but not touch the tip of their little finger, the nurse should suspect a specific motor deficit (impaired opposition) and document it. This would prompt a more detailed neurological workup, possibly by a physical or occupational therapist, to assess the integrity of the median nerve and intrinsic hand muscles.

How to Approach the Question

First, identify the key actions in the question: 'Movement of Thumb & Little finger towards each other'.
Recall the specific anatomical terms for movements of the digits.
Consider each option. 'Abduction' means moving away, and 'adduction' means moving towards the midline, which are general terms. 'Extension' means straightening.
Recognize that the thumb touching the fingertips is a special, named movement.
Select 'Opposition' as the term that specifically describes this unique and complex action of the thumb.

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 4 p. 137-139

E6 Anatomy BDChaurasia V1 10e p. 120-122

Practise the full PGIMER Sangrur NO - 2023

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