Sacrum

The sacrum is a large, triangular bone situated in the lower part of the vertebral column and at the upper and back part of the pelvic cavity. This unique piece of human anatomy interlocks with the hip bones to form the pelvis, providing a sturdy base for spinal structure and facilitating the weight transfer from the upper body to lower limbs.

Composed typically of five naturally fused vertebrae, this wedge-shaped structure plays an important role in balancing and sitting. Its anterior surface is smoother than its posterior counterpart which has several openings for passage of nerves and blood vessels.

Its shape, curvature, and location make it distinctive among other vertebral bones. It also serves as an attachment point for multiple muscles including those responsible for movement in our lower extremities.

**Exact Match Keyword:**
Sacrum

**N-Gram Classification:**
Single word

**Substring Matches:**
None

**Category:**
Anatomy

**Search Intent:**
Educational/Informational

**Semantic Relevance:**
Bone structure

**Parent Category:**
Human anatomy

**Subcategories:**
Pelvis, Vertebrae

**Synonyms:**
None

**Similar Searches:**
Sacral bone, Sacral vertebrae, Sacrum function

**Related Searches:**
Coccyx, Ilium, Lumbar vertebrae

**Geographic Relevance:**
N/A

**Topically Relevant Entities:**
Vertebral column, Pelvic girdle