Nail are involved in
**Core Concept**
Nail involvement is a common manifestation of various systemic and localized conditions. The nail anatomy consists of the nail plate, nail bed, cuticle, eponychium, and hyponychium. Any alteration in these structures can lead to nail changes.
**Why the Correct Answer is Right**
Nail involvement is often a result of trauma, infection, or systemic diseases affecting the nail matrix or nail bed. The nail matrix is responsible for nail plate production, while the nail bed provides a substrate for nail plate adherence. Conditions like psoriasis, lupus, and fungal infections can cause nail changes by affecting the nail matrix or nail bed. For instance, psoriasis leads to nail plate thickening and pitting due to abnormal nail matrix function.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.
**Clinical Pearl / High-Yield Fact**
Nail changes can be a valuable clue in diagnosing systemic conditions. For example, clubbing of the fingers and toes is often associated with lung cancer, while pitting of the nails is a characteristic feature of psoriasis.
**Correct Answer:** A, B, C, D