## **Core Concept**
Chordomas are rare, malignant bone tumors that arise from the remnants of the notochord. The notochord is a precursor to the spinal cord and is typically found in the axial skeleton. Chordomas most commonly occur at the ends of the axial skeleton, particularly in the sacrum, base of the skull (clivus), and less frequently in the spine.

## **Why the Correct Answer is Right**
The correct answer involves the common sites where chordomas are typically found. Chordomas have a predilection for the axial skeleton, particularly the **sacrum** and the **clivus** (base of the skull). The sacrum is one of the most common sites, and the clivus is another frequent location. These tumors can occur in other parts of the spine but are much less common.

## **Why Each Wrong Option is Incorrect**
- **Option A: Dorsal spine** - While chordomas can occur in the spine, they are much less common in the dorsal (thoracic) spine compared to the sacrum and clivus.
- **Option C: Lumbar spine** - Similar to the dorsal spine, the lumbar spine is an uncommon site for chordomas.
- **Option E: Cervical spine** - Though chordomas can occur here, they are less common than in the sacrum and clivus.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that chordomas are typically located in the midline, and their common sites are the **sacrum**, **clivus**, and less frequently, other parts of the vertebral column. Given their location, chordomas can cause a variety of symptoms depending on their site of origin, including pain and neurological deficits.

## **Correct Answer:** D.