AIIMS BBSR SNO - 2019: Carpal tunnel syndrome is caused by the compression of?

AIIMS BBSR SNO - 2019

Applied Anatomy

Easy

Appeared in: AIIMS BBSR SNO - 2019

Explanation

Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by the compression of the median nerve at the wrist.
The median nerve passes through the carpal tunnel, a narrow passageway formed by the carpal bones and the transverse carpal ligament.
Compression of this nerve leads to characteristic symptoms of pain, numbness, and paresthesia in the distribution of the median nerve: the thumb, index finger, middle finger, and the radial half of the ring finger.
The image provided visually confirms this anatomy, showing the median nerve situated within the carpal tunnel alongside flexor tendons.

Option B: The radial nerve is primarily responsible for wrist and finger extension. Its compression, typically in the upper arm, leads to 'wrist drop,' not the symptoms of carpal tunnel syndrome.
Option C: The ulnar nerve supplies sensation to the little finger and the ulnar half of the ring finger. Its compression occurs at the elbow (cubital tunnel syndrome) or wrist (Guyon's canal), causing symptoms in a different distribution than CTS.
Option D: The femoral nerve is a large nerve in the thigh and is not located in the arm or wrist. It is anatomically unrelated to carpal tunnel syndrome.

Clinical Relevance

Nursing practice connection: Knowing Anatomy and pathophysiology of Carpal Tunnel Syndrome helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses play a key role in managing CTS by educating patients on ergonomic modifications, applying wrist splints (especially at night to maintain a neutral position), and administering anti-inflammatory medications as prescribed.
Post-operatively, after a carpal tunnel release, nurses must perform regular neurovascular assessments of the hand to monitor for complications like nerve damage or impaired circulation.
What if? If a patient presented with numbness and tingling in their little finger and the adjacent half of their ring finger, the nurse should suspect ulnar nerve compression (e.g., cubital tunnel syndrome) instead of median nerve compression, prompting a different line of assessment.

How to Approach the Question

First, identify the key term in the question: 'Carpal tunnel syndrome'.
Recall the anatomical location of the carpal tunnel, which is in the wrist.
Access your knowledge of the major nerves of the upper limb and which one passes through this specific tunnel.
Analyze the options provided. The median nerve is the only nerve listed that passes through the carpal tunnel.
Eliminate the other nerves based on their known locations and functions: the radial nerve (associated with wrist drop), the ulnar nerve (associated with the little finger), and the femoral nerve (located in the leg).
Confirm the answer by correlating the function of the median nerve (sensation to thumb, index, middle fingers) with the classic symptoms of carpal tunnel syndrome.

Concept Tested & Keywords

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