Pterion

The pterion is the region where the frontal, parietal, temporal, and sphenoid bones join together.[1] It is located on the side of the skull, just behind the temple.

Pterion
Side view of head, showing surface relations of bones (Pterion labeled at center)
Side view of the skull with arrow pointing to the Pterion
Details
Identifiers
Latin	Pterion
TA	A02.1.00.019
FMA	264720
Anatomical terminology

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.[2]

It is the junction between four bones:

• the parietal bone
• the squamous part of temporal bone
• the greater wing of sphenoid bone
• the frontal bone

These bones are typically joined by five cranial sutures:

• the sphenoparietal suture joins the sphenoid and parietal bones
• the coronal suture 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

The pterion is known as the weakest part of the skull.[3] The anterior division of the middle meningeal artery runs underneath the pterion.[4] 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.

Etymology

The pterion receives its name from the Greek root pteron, meaning wing. In Greek mythology, Hermes, messenger of the gods, was enabled to fly by winged sandals, and wings on his head, which were attached at the pterion.

References

This article incorporates text in the public domain from page 182 of the 20th edition of Gray's Anatomy (1918)

1. R.M. McMinn.Last's anatomy regional and applied, 9th edition. Edinburgh (UK): Churchill Livingstone; 1994. Page 645
2. Siyan, MA; Louisa J.M. Baillie; Mark D. Stringer (April 2012). "Reappraising the surface anatomy of the pterion and its relationship to the middle meningeal artery". Clinical Anatomy. 25 (3): 330–339. doi:10.1002/ca.21232. PMID 21800374.
3. Garner, Jeff; Goodfellow, Peter (2004). Questions for the MRCS Vivas. p. 123.
4. Weston, Gabriel (22 August 2011). "Mapping the Body: The Temple". The Guardian. Retrieved 4 April 2012.

External links

• Anatomy figure: 22:01-04 at Human Anatomy Online, SUNY Downstate Medical Center
• Diagram - look for #24 (source here)