Bicortical

Bicortical refers to a medical or anatomical term describing something that involves or passes through both cortical layers of a bone. The cortex of a bone is the dense outer layer, and it consists of two distinct parts: the outer periosteal layer and the inner endosteal layer. Therefore, a bicortical structure or process would engage both of these layers.

In surgical contexts, the term is frequently used when describing the passage of screws or implants. A bicortical screw fixation, for example, means that the screw has penetrated and anchored into both the outer and inner cortices of a bone. This provides greater stability and strength to the fixation compared to monocortical fixation, where the screw only engages one cortical layer. This is particularly important in spinal fusion surgeries, where bicortical screw purchase in the vertebral bodies is often preferred for robust stabilization.

Anatomically, certain structures or pathways can be described as bicortical if they traverse both the outer and inner aspects of the bone's cortex. This understanding is crucial in fields like radiology, orthopedic surgery, and anatomy for accurate diagnosis and treatment planning. The integrity and thickness of the cortical layers can vary depending on the bone's location, age, and health, influencing the feasibility and technique of bicortical engagement.