Which of the following is the most common cause of fracture of roof of orbit?

Fractures of the orbital roof usually results from blow to the brow, often associated with a late-developing periorbital hematoma. The delay in swelling can be an impoant clue in differentiating fractures of the roof from other orbital injuries. Severe fractures of the orbital roof often are associated with fractures of the forehead combined with brain injury and dural tears with cerebrospinal fluid leakage. Ref: Head & Neck Surgery: Otolaryngology edited by Byron J. Bailey, Jonas T. Johnson, Shawn D. Newlands, 2006, Page 1346.