Which of the following elements is found within a normal periodontal membrane?

The periodontal membrane, also known as the periodontal ligament, plays a crucial role in supporting and anchoring the teeth within their sockets. Fibroblasts are a key component of this membrane, as they are responsible for synthesizing collagen and other extracellular matrix materials that provide structural integrity to the ligament. These cells also play a role in the repair and regeneration of periodontal tissues, making them essential for maintaining periodontal health.

While neurons and keratinocytes are present in various types of oral tissues, they do not have the same functional significance in the periodontal membrane as fibroblasts. Neurons can be involved in the sensation of pain or pressure, but they are not a predominant cellular component of the periodontal ligament itself. Keratinocytes are typically associated with epithelial tissues and are not found in the periodontal ligament. Osteocytes, on the other hand, are bone cells and are primarily located within bone tissue rather than in the periodontal membrane. Thus, fibroblasts are the correct answer as they are integral to the structure and function of the periodontal ligament.