The pterion is the region where the frontal, parietal, temporal, and sphenoid bones join. It is located on the side of the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, t ...

, just behind the

temple A temple (from the Latin ) is a building reserved for spiritual rituals and activities such as prayer and sacrifice. Religions which erect temples include Christianity (whose temples are typically called church (building), churches), Hindui ...

Structure

The pterion is located in the temporal fossa, approximately 2.6 cm behind and 1.3 cm above the posterolateral margin of the

frontozygomatic suture The zygomaticofrontal suture (or frontozygomatic suture) is the cranial suture between the zygomatic bone and the frontal bone. The suture can be palpated just lateral to the eye. Additional images File:Gray164.png, Left zygomatic bone in situ. F ...

. It is the junction between four bones: * the parietal bone. * the squamous part of

temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears ...

. * the greater wing of sphenoid bone. * the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...

. These bones are typically joined by five

cranial sutures In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones are ...

: * the sphenoparietal suture joins the sphenoid and parietal bones. * the

coronal suture The coronal suture is a dense, fibrous connective tissue joint that separates the two parietal bones from the frontal bone of the skull. Structure The coronal suture lies between the paired parietal bones and the frontal bone of the skull. ...

joins the frontal bone to the sphenoid and parietal bones. * the squamous suture joins the temporal bone to the sphenoid and parietal bones. * the sphenofrontal suture joins the sphenoid and frontal bones. * the sphenosquamosal suture joins the sphenoid and temporal bones.

Clinical significance

Haematoma

The pterion is known as the weakest part of the skull. The anterior division of the middle meningeal artery runs underneath the pterion. Consequently, a traumatic blow to the pterion may rupture the middle meningeal artery causing an epidural haematoma. The pterion may also be fractured indirectly by blows to the top or back of the head that place sufficient force on the skull to fracture the pterion.

Surgery

The pterion is a structural landmark for neurosurgical approach to middle cerebral artery

aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus ...

Etymology

The pterion receives its name from the Greek root ''pteron'', meaning ''

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is exp ...

''. In

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities of ...

Hermes Hermes (; grc-gre, Ἑρμῆς) is an Olympian deity in ancient Greek religion and mythology. Hermes is considered the herald of the gods. He is also considered the protector of human heralds, travellers, thieves, merchants, and orato ...

, messenger of the gods, was enabled to fly by winged sandals, and wings on his head, which were attached at the pterion.

References

External links

*
Diagram - look for #24
(sourc
here
{{Authority control Skull