A six-month-old baby has fallen out of the crib. An X-ray determines the baby has fractured their femur in one cortex of the bone and isn't showing a complete break. What type of fracture has occurred?

The fracture described in the case of the six-month-old baby is a greenstick fracture. This type of fracture is characteristic of pediatric patients due to the unique properties of their bones, which are softer and more pliable than adult bones.

In a greenstick fracture, one side of the bone is fractured while the other side remains intact, similar to how a young twig breaks partially while not completely severing. This aligns with the description of the baby having a fracture in one cortex of the femur without a complete break, indicating that the bone bent and broke on one side but did not fully fracture through.

In contrast, other types of fractures such as transverse, spiral, and comminuted involve different patterns of injury. A transverse fracture features a straight break across the bone, a spiral fracture is caused by a twisting force that creates a helical break around the bone, and a comminuted fracture results in the bone being shattered into multiple pieces. None of these descriptions fit the situation presented in this case, making greenstick the only appropriate choice.