**Core Concept**
Inflammatory arthritis, such as rheumatoid arthritis, is characterized by inflammation of the synovial lining, leading to joint swelling, warmth, and tenderness. In contrast, osteoarthritis is a degenerative joint disease marked by wear and tear of the cartilage, resulting in bony changes and crepitus.

**Why the Correct Answer is Right**
Swelling and warmth are key clinical signs of inflammation, indicating an increase in synovial fluid and blood flow to the affected joint. This is a hallmark of inflammatory arthritis, such as rheumatoid arthritis or psoriatic arthritis. The presence of swelling and warmth suggests an active inflammatory process, rather than the degenerative changes seen in osteoarthritis. In contrast, osteoarthritis typically presents with bony changes, crepitus, and a painful range of motion due to joint degeneration and loss of cartilage.

**Why Each Wrong Option is Incorrect**
**Option A:** Painful range of motion can be seen in both inflammatory and osteoarthritis, as it is a non-specific symptom that can result from joint inflammation or degeneration.

**Option B:** Crepitus, or the sensation of grating or grinding, is often associated with osteoarthritis, where it is caused by the roughening of bone ends due to cartilage loss.

**Option C:** Bony articular enlargement can be seen in both inflammatory and osteoarthritis, as a result of joint inflammation and degeneration.

**Clinical Pearl / High-Yield Fact**
When evaluating joint pain, remember that the presence of swelling and warmth is a red flag for inflammatory arthritis, and warrants further investigation and treatment.

**Correct Answer:**
✓ Correct Answer: D. Swelling and warmth.