Final answer:
The dural sac ends at the S2 level in adults. The cervical region of the vertebral column has the greatest range of motion for rotation due to its anatomical structure, which is designed for head support and flexible movement.
Step-by-step explanation:
The dural sac in adults typically ends at the level of the second sacral vertebra (S2). The vertebral column is divided into various regions which include the cervical, thoracic, lumbar, and sacral regions. Looking at the vertebral column’s motion for rotation, the region with the greatest range is the cervical region, specifically the C1-C7 vertebrae. This is due to the fact that the cervical vertebrae are designed to support the head and allow for extensive movement in multiple directions, including rotation.
- Cervical (C1-C7 vertebrae): Allows for a large range of motion, including rotation.
- Thoracic (T1-T12 vertebrae): This region has a limited range of motion for rotation due to the attachment of the ribs.
- Lumbar (L1-L5 vertebrae): Has a limited range of motion in rotation; its movement is mainly flexion and extension.
- Sacral (fusion of sacral vertebrae): Very limited movement due to its role in connecting the spine to the pelvis.