Infantile acute subdural hemorrhage probably caused by injury to the diploic channels.

A 6-month-old, previously healthy boy hit the right frontal region of his head against the corner of a plastic toy box. At presentation, a small area with scalp discoloration was noted in the right frontal region. Head computed tomography at the level of discoloration revealed an intracranial hematoma, 5 mm in maximal thickness, below the coronal suture. In addition, there were bony bridges connecting the frontal and parietal bones. Furthermore, a linear crack was found in the diploe of the frontal bone in contact with the coronal suture. Cerebral MRI confirmed linear hyperintensity between the inner tables. We assumed that a kind of ping-pong ball fracture was caused by the head blow, centering on the coronal suture, resulting in rupture of contacting diploic channels and tear of the dura mater, and forming a subdural hematoma. Acute subdural hemorrhage may be caused by an insignificant blow to the coronal suture in infantile patients with underdeveloped cranial bones and sutures, accompanied by subtle external findings.