Okay, let's tackle this question. The user mentioned the "Positive metacarpal sign" and wants to know which condition it's associated with. First, I need to recall what the metacarpal sign is. From what I remember, it's a clinical sign used in diagnosing certain hand conditions, maybe something related to the metacarpal bones.

Wait, the metacarpal sign—maybe it's related to a specific test? Let me think. Oh, right! The metacarpal sign is used in the assessment of carpal tunnel syndrome. When the patient makes a fist, the metacarpal bones become prominent, and in carpal tunnel syndrome, there's thenar atrophy which makes the metacarpal heads more pronounced. So a positive sign would indicate that prominence, pointing towards carpal tunnel syndrome.

But wait, are there other conditions where this sign is positive? Let me check. Conditions like Dupuytren's contracture might cause hand deformities, but I don't think that's linked to the metacarpal sign. Maybe rheumatoid arthritis? It can cause joint deformities, but again, not the specific metacarpal sign. The key here is the prominence of the metacarpal heads, which is a classic sign of thenar atrophy seen in chronic carpal tunnel syndrome.

So the correct answer should be carpal tunnel syndrome. The other options might include things like ganglion cysts, De Quervain's tenosynovitis, or others. The distractors would be incorrect because they don't present with thenar atrophy or the prominence of the metacarpal heads. For example, De Quervain's affects the thumb, and ganglion cysts are lumps, not related to bone prominence. So the clinical pearl here is that the metacarpal sign is a key indicator of carpal tunnel syndrome, especially when thenar atrophy is present. That's the high-yield fact students should remember.

**Core Concept**
The metacarpal sign assesses thenar eminence atrophy, a hallmark of chronic **carpal tunnel syndrome (CTS)**. It is elicited by observing the prominence of metacarpal heads during hand closure, indicating denervation of the thenar muscles due to median nerve compression.

**Why the Correct Answer is Right**
In chronic CTS, prolonged median nerve compression leads to **thenar muscle atrophy**. When the hand is clenched, the atrophied thenar eminence fails to pad the metacarpal heads, causing their prominence. This sign is pathognomonic for CTS and correlates with irreversible nerve damage if untreated. The median nerve’s sensory and motor deficits (e.g., loss of thumb opposition) further confirm the diagnosis.

**Why Each Wrong Option is Incorrect**
**Option A:** "Ganglion cyst" – These are benign masses, not linked to thenar atrophy or metacarpal prominence.
**Option B:** "Rheumatoid arthritis" – Causes joint deformities (e.g., ulnar deviation), not metacarpal head prominence.
**Option C:** "De Quervain’s tenosynovitis" – Involves thumb extensor tendons, not thenar muscles or metacarpal bones.

**Clinical Pearl / High-Yield

✓ Correct Answer: C. Turners Syndrome