7: The Brain, Cerebral Arterial Circle, Dura Mater, Venous Sinuses and Cranial Fossa
Introduction - Overview - Identification - Summary - Imaging - Clinical Case Study
Epidural Hematoma

A 22 year old biology student was struck by a puck on the left "temple" (temporal fossa) during an intramural hockey game. He fell to the ice unconscious but regained consciousness in about one minute. There was bleeding from a laceration located two fingers' breadth above his left zygomatic arch that extended from the top of his ear almost to his eyebrow.

As you helped him to the bench, he said he felt rather weak and unsteady. Realizing he may have sustained a skull fracture, you summoned a doctor and helped your friend to the locker room. As you waited, you noticed his pupils were equal in size and both constricted to light. You also observed the injury site started to swell, but otherwise your friend seemed okay.

After about half and hour he said he was sleepy and wanted to lie down. His left pupil was moderately dilated and reacted to light. By the time the doctor arrived he was unconscious. His left pupil was widely dilated and did not respond to light, whereas his right pupil was slightly dilated but showed a normal reaction to light. The doctor immediately ordered an ambulance and he was taken to the hospital for a CT scan which revealed he had sustained a fracture of the squamous portion of the temporal bone.

QUESTIONS

  1. What other structure, within the cranial vault, probably was damaged by the bone fragments of his skull fracture?
  2. What is the formal terminology of this pathological condition resulting from damage to this structure?
  3. What is the anatomical relationship of this structure to the meninges?
  4. Why were the pupils dilated and unresponsive to light?