What is pterion and asterion?

The pterion and asterion are at the outer surface of the skull. The pterion is the region where the frontal, sphenoid, parietal and temporal bones join together, and the asterion is the intersection of parietal, temporal and occipital bones. The sutural pattern of both are different in the various population and races.

What is the location of asterion?

The asterion is an anatomical landmark on the lateral aspect of the skull formed at the junction of the occipital bone, the temporal bone, and the parietal bone.

What sutures meet at the asterion?

It is the point where three cranial sutures meet: the lambdoid suture. parietomastoid suture. occipitomastoid suture.

Why is pterion clinically significant?

The pterion is known as the weakest part of the skull. Clinically, the pterion is relevant because the middle meningeal artery runs beneath it, on the inner side of the skull, which is quite thin at this point. A blow to the pterion (e.g. in boxing) may rupture the artery causing an extradural haematoma.

What is a pterion?

The pterion is a craniometric point near the sphenoid fontanelle of the skull. It is a point of convergence of the sutures between the frontal, sphenoid, parietal, and squamous temporal bones [1]. There are varied patterns of articulation of these bones and sometimes a small epipteric bone may be present.

What does pterion mean?

Medical Definition of pterion : the point on each side of the skull where the parietal and temporal bones meet the greater wing of the sphenoid.

What happens pterion?

2.2 – Classification of Patterns at Pterion The SP pattern occurs when the sphenoid and the parietal bone articulate and prevent the frontal and the temporal bone from making contact. The FT pattern occurs when the frontal and temporal bones articulate preventing the sphenoid and the temporal bone from making contact.

How do you find pterion?

The pterion center was located at a mean distance of 37.02 mm above the midpoint of zygomatic arch, 28.20 mm behind the posterolateral margin of frontozygomatic suture, 42.73 mm lateral to the optic canal and 10.59 mm from the sphenoid ridge.

Why is the pterion so weak?

Pterion is a point of clinical significance – the skull is very thin at this point. In addition to being structurally weak due to being the point of union between several bones, it also lies over the anterior division of the middle meningeal artery.

What is bregma?

Definition of bregma : the point of junction of the coronal and sagittal sutures of the skull.

What artery is at pterion?

the middle meningeal artery
The anterior branch of the middle meningeal artery runs beneath the pterion. It is vulnerable to injury at this point, where the skull is thin. Rupture of the artery may give rise to an epidural hematoma.

What happens when pterion is damaged?

Rupture of the artery, which most commonly occurs at the pterion, typically leads to an epidural hematoma. The resulting hematoma is described as a “lens-shaped” mass on a computed tomogram (CT) scan. Damage to the middle meningeal artery may also result in an aneurysm or arteriovenous fistulas.

What 4 bones meet at the pterion?

What bones form pterion?

The pterion is an H-shaped bony neurological landmark found at the junction of the frontal, sphenoid, parietal and the squamous part of temporal bone (1). It is located approximately 4 cm superior to the zygomatic arch and 3.5 cm posterior to the frontozygomatic suture (2).

What is the meaning Hypallage?

Definition of hypallage : an interchange of two elements in a phrase or sentence from a more logical to a less logical relationship (as in “a mind is a terrible thing to waste” for “to waste a mind is a terrible thing”)