Why a Blow to the Temple Can Be Fatal
A strike to the side of the head may appear trivial, but the region known as the pterion is uniquely vulnerable. Beneath this thin region of the skull lies the anterior division of the middle meningeal artery (MMA), a vessel whose injury can rapidly produce a life-threatening epidural hematoma. Understanding this anatomy is essential for quick clinical recognition.
Anatomy of the Pterion
The pterion is the junction where four skull bones meet—the frontal, parietal, temporal, and sphenoid bones. This area of the calvaria is the thinnest part of the lateral skull. The underlying temporal bone is particularly fragile, offering minimal protection for deeper neurovascular structures.
Middle Meningeal Artery: The Critical Structure
The MMA enters the cranial cavity through the foramen spinosum and ascends between the dura mater and the inner surface of the skull. Its anterior branch courses precisely beneath the pterion. Because the dura is tightly adherent to the bone here, even a small fracture can tear the artery.
The vessel lies between the cranial bone and the dura mater, making this region susceptible to accumulation of arterial blood in the extradural space.
How an Epidural Hematoma Forms
When the anterior branch of the MMA is ruptured, high-pressure arterial blood dissects the dura from the inner table of the skull, producing an epidural hematoma. This accumulation expands rapidly, increasing intracranial pressure and compressing adjacent brain tissue.
Classically, the patient may experience a transient loss of consciousness followed by a lucid interval. As the hematoma enlarges, neurological deterioration occurs due to uncal herniation and brainstem compression.
Why a Small Impact Can Be Deadly
Three anatomical features explain the danger:
- The pterion is extremely thin and fractures easily.
- The MMA’s anterior branch runs tightly against this bone without muscular or soft-tissue protection.
- Arterial bleeding into the extradural space expands quickly and does not tamponade.
Because of these factors, even a seemingly insignificant blow—sports injury, fall, or assault—can result in rapid neurological decline if unrecognized.
Clinical Significance
Any head trauma localised to the temple region must be considered high risk. Rapid identification using CT imaging and emergent neurosurgical intervention can be life-saving. The anatomical relationship between the pterion and the middle meningeal artery forms the basis for this critical emergency.