**Core Concept**
Kanavel's sign refers to a set of four cardinal signs used to diagnose acute suppurative flexor tenosynovitis, a condition characterized by inflammation of the tendon sheath surrounding the flexor tendons in the fingers. These signs are essential for differentiating this condition from other tenosynovial pathologies.

**Why the Correct Answer is Right**
The cardinal signs of Kanavel's sign include:
- Dactylitis: swelling of the entire digit
- Tenderness along the course of the flexor tendon
- Reduced mobility of the affected finger
- Puncture or fluctuance of the tendon sheath

These signs are indicative of the inflammatory process and the accumulation of pus within the tendon sheath. The presence of these signs is crucial for diagnosing acute suppurative flexor tenosynovitis and guiding appropriate treatment.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to Kanavel's sign, as it is more related to other conditions.
**Option B:** While pain is a symptom of many conditions, it is not a specific sign of Kanavel's sign.
**Option C:** This option is incorrect as it does not describe a characteristic feature of Kanavel's sign.

**Clinical Pearl / High-Yield Fact**
Kanavel's sign is a classic clinical diagnosis that should be remembered by all surgeons and emergency physicians to promptly identify acute suppurative flexor tenosynovitis and initiate appropriate treatment.

**Correct Answer:** D.