The collagen fibers of the periodontal ligament are grouped into what arrangement?

• A. Bundles
• B. Sheets
• C. Fibers
• D. Lamellae

Answer: (A)

Collagen in the periodontal ligament is organized into bundles (fascicles). These bundles run in multiple directions from the cementum of the tooth root to the surrounding alveolar bone, forming a network that can resist forces from different directions. This bundled arrangement provides the tensile strength and flexibility needed to distribute chewing loads safely and to stabilize the tooth within the socket. When collagen is grouped into bundles, you get Sharpey's fibers where the bundles extend into cementum and bone, reinforcing attachment and load transfer. Other terms like sheets imply a flat, layered arrangement, and lamellae refer to layered structures more typical of bone or other tissues, while simply saying fibers misses the organized, hierarchical grouping essential for function.