Xiphoid fuses with sternum by what age ?
**Core Concept**
The xiphoid process is the lowest part of the **sternum**, and its fusion with the rest of the sternum is an important anatomical landmark. This process is related to **bone development** and **ossification**. The timing of this fusion is crucial for understanding **thoracic anatomy**.
**Why the Correct Answer is Right**
The xiphoid process typically fuses with the rest of the sternum by around **40 years of age**. This fusion is a gradual process that occurs through **ossification**, where the cartilaginous part of the xiphoid process is replaced by bone. The exact timing can vary among individuals due to factors such as **genetics** and **hormonal influences**.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it suggests an age that is too early for xiphoid fusion.
**Option B:** Similarly, this option is also incorrect as it proposes an age that does not align with the typical timeframe for xiphoid fusion.
**Option D:** This option is incorrect because it suggests an age that is too late for the completion of xiphoid fusion.
**Clinical Pearl / High-Yield Fact**
Remember that the xiphoid process serves as an important landmark for **thoracic** and **abdominal surgery**, and its fusion with the sternum can affect the approach to certain procedures.
**Correct Answer:** C. 40 years.