The pterion is the region where the

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music * The Front (band), an American rock band signed to Columbia Records and active in the 1980s and e ...

, 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, the ...

, 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 churches), Hinduism (whose temples ...

Structure

The pterion is located in the

temporal fossa The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. Boundaries * Medial: frontal bone, parietal bone, temporal bone, and sphenoid bon ...

, approximately 2.6 cm behind and 1.3 cm above the posterolateral margin of the frontozygomatic suture. It is the junction between four bones: * the

parietal bone The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, an ...

. * 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. Th ...

. * the

greater wing The greater wing of the sphenoid bone, or alisphenoid, is a bony process of the sphenoid bone; there is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally, and backward. Structure The greater wi ...

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...

. * 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, par ...

. These bones are typically joined by five

cranial sutures In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of c ...

: * the

sphenoparietal suture The sphenoparietal suture is the cranial suture between the sphenoid bone and the parietal bone. It is one of the sutures that comprises the pterion. Additional images File:Sphenoparietal suture.gif, Position of sphenoparietal suture (shown in ...

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. It r ...

joins the frontal bone to the sphenoid and parietal bones. * the

squamous suture The squamosal suture, or squamous suture, arches backward from the pterion and connects the temporal squama with the lower border of the parietal bone: this suture is continuous behind with the short, nearly horizontal parietomastoid suture, whic ...

joins the temporal bone to the sphenoid and parietal bones. * the

sphenofrontal suture The sphenofrontal suture is the cranial suture between the sphenoid bone and 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 squamo ...

joins the sphenoid and frontal bones. * the

sphenosquamosal suture The sphenosquamosal suture is a cranial suture between the sphenoid bone and the squama of the 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 te ...

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 The middle meningeal artery ('' la, arteria meningea media'') is typically the third branch of the first portion of the maxillary artery. After branching off the maxillary artery in the infratemporal fossa, it runs through the foramen spinosum to ...

runs underneath the pterion. Consequently, a traumatic blow to the pterion may rupture the middle meningeal artery causing an

epidural haematoma Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain (dura mater) and the skull. Often there is loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciou ...

. 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 Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peri ...

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 (s ...

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 expres ...

''. In

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

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