Which of the following contains an incorrect definition?

• A. Causalgia: severe pain caused by dry skin.
• B. Cryogenic: produces cold.
• C. Subungual: under the nail.
• D. Autotoxin: substance produced by organism which is toxic to the organism itself.

Answer: (A)

Verified step by step guidance

1. Step 1: Review each term and its given definition carefully to understand the meaning of the medical terminology.
2. Step 2: Analyze 'Cryogenic' which is defined as 'produces cold.' This is correct because 'cryo-' means cold and '-genic' means producing or causing.
3. Step 3: Analyze 'Subungual' which is defined as 'under the nail.' This is correct because 'sub-' means under and 'ungual' relates to the nail.
4. Step 4: Analyze 'Autotoxin' which is defined as 'substance produced by organism which is toxic to the organism itself.' This is correct because 'auto-' means self and 'toxin' means poison.
5. Step 5: Analyze 'Causalgia' which is defined as 'severe pain caused by dry skin.' This is incorrect because 'causalgia' actually means severe burning pain usually caused by nerve injury, not dry skin.