Which one of the following is radiolucent stone: September 2007
**Core Concept**
The question tests the understanding of **urinary stone** composition and their radiographic appearance, specifically focusing on **radiolucent stones**. Urinary stones can be composed of various materials, including calcium oxalate, uric acid, and cystine, each with different radiographic properties.
**Why the Correct Answer is Right**
Uric acid stones are **radiolucent**, meaning they do not show up on plain X-ray films because they do not contain calcium. This characteristic makes them distinct from other types of stones like calcium oxalate stones, which are radiopaque due to their calcium content.
**Why Each Wrong Option is Incorrect**
**Option A:**
**Option B:**
**Option C:**
**Option D:**
Given the lack of specific options, it's known that uric acid stones are typically radiolucent, so any option not representing uric acid stones would be incorrect.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **uric acid stones** are often associated with conditions that increase uric acid production or decrease its excretion, such as gout or certain malignancies. Recognizing the radiolucent nature of these stones can aid in their diagnosis.
**Correct Answer:** D. Uric acid stone