A 36-year-old man was admitted to the emergency department unconscious. He had been hit on the side of the head by a taxi while crossing the road. On examina- tion, he was found to have a dough-like swelling over the right temporalis muscle. He also had the signs of rightsided hemiplegia. Later, a right-sided, fixed, dilated pupil developed. A lateral radiograph of the skull showed a linear fracture running downward and forward across the right pterion. His coma deepened, and he died 6 hours
after the accident. Using your knowledge of anatomy, make the diagnosis. Explain the clinical findings. How would you explain the homolateral hemiplegia?

Question

Quizplus · Accepted Answer

The Answer is The initial loss of consciousness was due to cerebral trauma. The swelling over the right temporalis muscle and the radiographic finding of a linear fracture over the anterior inferior angle of the right parietal bone (pterion) would suggest that the right middle meningeal artery had been damaged and an extradural hemorrhage had occurred. Blood had extravasated through the fracture line into the overlying temporalis muscle and soft tissue. The right homolateral hemiplegia was due to the compression of the left cerebral peduncle against the edge of the tentorial notch of the tentorium cerebelli. This is unusual. A left hemiplegia due to pressure on the right precentral gyrus is more common.
The right-sided, fixed, dilated pupil was due to the pressure on the right oculomotor nerve by the hippocampal gyrus, which had herniated through the tentorial notch.

A 36-Year-Old Man Was Admitted to the Emergency Department Unconscious