Importance of Pterion

The pterion is area where four bones, the pariental and frontal bones, the greater wing of the sphenoid bone, and the squamous part of the temporal bone, approach each other.

The pterion overlies the anterior branch of the middle meningeal artery on the internal aspect of the skull, and it corresponds to the stem of the lateral sulcus of the brain.

The center of the pterion is about 4 cm above the midpoint of the zygomatic arch and nearly the same distance behind the zygomatic process of the frontal bone.

The pterion is identifying as the weakest part of the skull.

Clinically, the pterion is relevant because the anterior division of the middle meningeal artery runs beneath it, on the inner side of the skull, which is quite thin at this point. The combination of both a vital artery in this area and the relatively thin bone structure has lent itself to the name "God's little joke" by some physicians.

A blow to the pterion (e.g. in boxing) may rupture the artery causing an extradural haematoma. The pterion may also fracture indirectly. Blows to the top or back of the head may not cause fracture at the site of impact, but may place sufficient force on the skull that its weakest part, the pterion, will fracture.