Which bone does NOT participate in forming the pterion?

Which bone does NOT participate in forming the pterion?

• A. Occipital
• B. Frontal
• C. Parietal
• D. Sphenoid

Answer: (A)

The pterion is a thin, hatchet-shaped junction where four bones come together: the frontal bone, the parietal bone, the greater wing of the sphenoid, and the temporal bone. The occipital bone does not participate in this junction; it is located posteriorly and forms sutures with the parietal and temporal bones in other regions, not at the pterion. This area is clinically important because the underlying middle meningeal artery runs beneath it, so trauma here can lead to an epidural hematoma.

The pterion is a thin, hatchet-shaped junction where four bones come together: the frontal bone, the parietal bone, the greater wing of the sphenoid, and the temporal bone. The occipital bone does not participate in this junction; it is located posteriorly and forms sutures with the parietal and temporal bones in other regions, not at the pterion. This area is clinically important because the underlying middle meningeal artery runs beneath it, so trauma here can lead to an epidural hematoma.