The temple is the slightly concave region on each side of your head, roughly between the outer edge of your eyebrow and the top of your ear. What makes it medically noteworthy is that the bone here is among the thinnest anywhere on the skull, and just beneath it runs a major artery that supplies blood to the membranes surrounding the brain. A hard blow to this spot can fracture the bone and tear that artery, creating a life-threatening bleed inside the skull far more easily than a similar blow almost anywhere else on the head. That combination of thin bone and critical blood supply is what gives the temple its reputation as one of the body’s most vulnerable points.
The Bones That Meet at the Temple
When people say “the temple,” they are usually pointing at the area around a bony junction called the pterion. The pterion is the spot where four skull bones converge: the frontal bone (your forehead), the parietal bone (the upper side of your skull), the temporal bone (the lower side), and the greater wing of the sphenoid bone (a butterfly-shaped bone deep in the skull base).1PubMed Central. Morphological and Morphometric Analysis of the Pterion and Its Neurosurgical Implications You can feel this area on yourself: place your fingertips on your head just behind and above your eye socket, in the shallow depression where the temporalis muscle sits. The bone beneath your fingers there is noticeably thinner than the top or back of your skull.
Measurements from cadaver studies illustrate the difference starkly. At the midpoint of the pterion, average skull thickness is about 4.4 mm. But at its thinnest point in the surrounding squamous temporal bone, thickness drops to as little as 1 mm.2PubMed. Reappraising the surface anatomy of the pterion and its relationship to the middle meningeal artery For comparison, the skull at the top of the head or the back of the head is often 6 to 7 mm thick and reinforced by internal ridges. The temple simply lacks that structural reinforcement.
Why a Major Artery Runs Right Behind Thin Bone
The middle meningeal artery, or MMA, is the main blood supply to the dura mater, the tough membrane that lines the inside of the skull and protects the brain. The artery enters the skull through a small hole near the base, then runs upward along the inner surface of the temporal bone, branching as it goes. Its anterior branch passes directly behind the pterion. One study measuring the distance between the center of the pterion and the groove carved by the MMA found an average gap of only about 12 mm.3International Journal of Drug Delivery Technology. Morphometric study of pterion and its relation with middle meningeal artery in dry human skulls In roughly two-thirds of adults, a circle just one centimeter wide centered on the pterion directly overlaps the anterior branch of the artery.2PubMed. Reappraising the surface anatomy of the pterion and its relationship to the middle meningeal artery
This anatomy creates an unfortunate pairing. The thinnest patch of skull sits directly over a pressurized artery. A fracture here does not just crack bone; it can rip open the artery, which then bleeds into the tight space between the skull and the dura. Because there is virtually no room for extra fluid inside the skull, even a relatively small volume of blood can compress the brain rapidly.
The Epidural Hematoma and the Lucid Interval
When the MMA tears from a temple fracture, the resulting bleed is called an epidural hematoma. Blood pools between the skull bone and the outer brain membrane, forming a lens-shaped clot that presses inward on the brain. This is a surgical emergency. Without treatment, the expanding clot can push the brain downward through the opening at the skull’s base, a process called herniation, which is often fatal.
One of the most dangerous features of an epidural hematoma is something called the lucid interval. After the initial impact, a person may briefly lose consciousness, then wake up and appear alert and functional for minutes to hours, only to deteriorate suddenly as the clot grows large enough to compress the brain.4Journal of Angiotherapy. Multidisciplinary Approach to the Management of Traumatic Epidural Hematoma: Pathophysiology, Treatment, and Outcomes This interval has caused countless people to refuse medical attention, or to be sent home from emergency rooms, because they seemed fine. It is the main reason that any significant blow to the temple should be treated seriously even if the person feels well afterward. The window for surgical intervention can be narrow, and CT imaging can detect the bleed long before symptoms return.
CT angiography is used in emergency settings to check whether the MMA itself is damaged. In patients with acute epidural hematomas, imaging can reveal pseudoaneurysms of the artery, small balloon-like outpouchings at the injury site, sometimes only 1.5 to 2.8 mm across.5PubMed Central. Computed tomography angiography for detection of middle meningeal artery lesions associated with acute epidural hematomas These pseudoaneurysms can re-bleed if not treated, making accurate imaging essential.
Temporal Bone Fractures Beyond the Pterion
The pterion is the most famous weak point at the temple, but the entire temporal bone is thinner than most of the skull, and fractures here are common in head trauma more broadly. In one study of 60 patients with temporal bone fractures at a major referral hospital, the squamous portion of the temporal bone (the broad, flat area that makes up much of the temple region) was involved in about 44% of fracture cases.6PubMed Central. Imaging Patterns of Temporal Bone Fracture among Patients with Head Injury at Tikur Anbessa Specialized Hospital, Ethiopia In that same group, the longitudinal fracture pattern, where the fracture runs roughly parallel to the long axis of the temporal bone, was the most common type, accounting for about 78% of one-sided cases.
Temporal bone fractures carry consequences beyond the immediate bleed risk. The temporal bone houses the middle and inner ear structures, so fractures here can damage hearing and balance. Injuries to the middle ear may cause conductive hearing loss by disrupting the chain of tiny bones that transmit sound. Damage that extends into the inner ear’s otic capsule, the dense shell protecting the cochlea and semicircular canals, can cause sensorineural hearing loss, vestibular dysfunction, or cerebrospinal fluid leaks.7PubMed Central. Report of an Otic Capsule Disrupting Fracture of the Temporal Bone: Visualization of Pneumolabyrinth and Functional Assessment Facial nerve paralysis is another risk, because the facial nerve runs through a canal inside the temporal bone.8Neurotrauma. Management of Temporal Bone Fractures
A retrospective review of 152 patients with temporal bone fractures found that disruption of the ossicular chain (the tiny hearing bones) occurred in about 12% of patients, and otic capsule violation in about 6%. Patients over 60 with these fractures faced a relative risk of death more than three times higher than younger patients.9PubMed Central. Hearing and Mortality Outcomes following Temporal Bone Fractures That elevated mortality is partly because older adults are more likely to be on blood-thinning medications and have less physiological reserve to tolerate brain compression.
Not Everyone’s Pterion Looks the Same
The four bones at the pterion do not always meet in the same pattern. Anatomists have identified several configurations, and they vary meaningfully across populations. The most common arrangement is called the sphenoparietal type, where the sphenoid and parietal bones meet each other directly at the center, keeping the frontal and temporal bones separated. This pattern was found in about 86% of Nigerian skulls in one study,10PubMed Central. Study of the Location and Morphology of the Pterion in Adult Nigerian Skulls but only about 70 to 75% on each side in an Indian skull series.11PubMed Central. Morphometric Evaluation of Sutural Patterns at the Pterion and Asterion in Dry Indian Skulls: Surgical Relevance
Other configurations include the frontotemporal type, where the frontal and temporal bones meet instead, and the stellate type, where all four bones converge at a single point. Some skulls also have an extra small bone, called an epipteric bone, wedged into the junction. In the Indian skull study, the epipteric variety was the second most common pattern at about 11 to 13% per side, while in the Nigerian sample no epipteric types were found at all. These differences matter in surgery: a surgeon planning to drill into the skull at the pterion needs to know the local anatomy precisely, because the relationship between the bone junction and the underlying artery shifts depending on which pattern is present. The distance between the pterion’s center and the MMA groove varies with pterion type in a statistically meaningful way.3International Journal of Drug Delivery Technology. Morphometric study of pterion and its relation with middle meningeal artery in dry human skulls
Children’s Temples Are Even More Fragile
If adult temporal bone can be as thin as 1 mm, the situation in young children is more precarious still. Skull bone thickness increases with age, and in early childhood the temporal bone has not yet reached adult dimensions. Research on pediatric patients in Japan found that bone thickness in the temporal region correlated positively with age, with children under age two showing no significant thickness difference between measurement sites. A 3 mm thickness threshold, considered a minimum for certain surgical implants, was not reached in half of children until about age five to six, and not in 90% until around age ten to thirteen, depending on the exact location.
This developmental trajectory has practical consequences. Young children are more vulnerable to temple injuries from falls, which are the leading cause of head trauma in toddlers. It also means that infants who suffer non-accidental head trauma are at particular risk for temporal bone fractures and the dangerous bleeding that follows. Pediatric helmets and car seat head supports are designed with this vulnerability in mind, though the temple region remains difficult to fully protect in most helmet designs, as discussed below.
Helmets, Combat Sports, and Protecting the Temple
The temple’s vulnerability has direct implications for helmet design. Standard bicycle helmets, for example, tend to focus their coverage on the crown and back of the head. A study testing lateral impacts to helmeted heads found that in seven of eight tests using common-design bicycle helmets, the temporal area still made contact with the striking surface, and in one case a skull fracture occurred despite the helmet. Helmets with extended temporal coverage consistently prevented that contact.12PubMed. Lateral head impacts and protection of the temporal area by bicycle safety helmets This is a known gap in many recreational helmet designs: the sides of the head are left partly exposed to keep the helmet lightweight and well-ventilated.
In combat sports, the temple is a well-known target. Fighters learn early that a hook punch landing cleanly on the temple can produce a knockout more reliably than hits to other parts of the skull. A systematic review of injuries in mixed martial arts found that fighters sustained an average of about 16 significant head impacts per sparring session, and noted no major sex difference in impact magnitude, though lighter fighters absorbed more head punches than heavier ones.13PubMed Central. Injuries in Mixed Martial Arts After Adoption of the Unified Rules of MMA: A Systematic Review The temple’s susceptibility to knockout is not just about the thin bone. The brain sits loosely inside the skull, suspended in cerebrospinal fluid, and a lateral impact at the temple produces rotational acceleration of the brain that is especially effective at disrupting the brainstem’s reticular activating system, which maintains consciousness.
Military helmets, motorcycle helmets, and football helmets all extend further down the sides of the head than bicycle helmets, reflecting the higher-velocity impacts those activities involve. Even so, the temple remains a weak spot in head protection engineering. Any helmet that needs to allow peripheral vision and jaw movement must leave some of the temporal region exposed or lightly covered.
Why Surgeons Deliberately Cut Through the Temple
Paradoxically, the same thinness and anatomical relationships that make the temple dangerous in trauma make it useful in neurosurgery. The pterional craniotomy, where a surgeon removes a small window of bone at the pterion to access the brain, is one of the most common approaches in neurosurgical practice. It provides a direct line of sight to structures deep in the brain, including the arteries at the base of the brain, the optic nerves, and tumors growing near the skull base.14PubMed Central. Pterional Craniotomy With Anterior Clinoidectomy for the Resection of a Sphenoid Ridge Meningioma: A Case Report and Two-Dimensional Operative Video The thinness of the bone means less drilling is needed, and the pterion’s position on the lateral skull gives access to the middle cranial fossa without having to retract the brain excessively.
The relationship between the pterion and the MMA, so dangerous in trauma, is actually advantageous in controlled surgery because surgeons know exactly where the artery lies. Cadaver studies have mapped the pterion’s surface location precisely: in most adults, it falls within a one-centimeter circle located about 2.6 cm behind and 1.3 cm above the easily palpable outer edge of the brow ridge.2PubMed. Reappraising the surface anatomy of the pterion and its relationship to the middle meningeal artery This predictability allows surgeons to plan their approach with confidence, avoiding the artery when it is not the target and finding it quickly when it is. The anatomical variation in pterion types across populations is one reason preoperative imaging and population-specific anatomical data remain important for surgical planning.15PubMed. Surgical anatomy of the pterion and its relationship to the middle meningeal artery in optimizing pterional craniotomies: a cadaveric perspective
Nerve Damage and the Risk of Facial Paralysis
The temple region is not just about bone and arteries. Running through the soft tissue over the temple is the temporal branch of the facial nerve, which controls the muscles that raise your eyebrow and close your upper eyelid. This nerve is vulnerable during any surgery or trauma in the area. Research mapping the nerve’s course identified a danger zone about 40 degrees wide and 1.5 cm long near the level of the outer corner of the eye, particularly over the zygomatic arch and within about 2.5 cm in front of the tragus (the small flap of cartilage in front of your ear canal).16PubMed Central. Neurosurgical Importance on Temporal Branch of the Facial Nerve
Damage to this nerve branch results in an inability to raise the eyebrow on that side and difficulty fully closing the eye, which can lead to corneal drying and vision problems. Cosmetic procedures like facelifts, as well as neurosurgical approaches through the temple, must navigate carefully around this zone. The nerve runs in the superficial layers of tissue, not deep inside the skull, so even relatively minor lacerations or blunt injuries to the temple skin can sometimes injure it.
When Disease Thins the Temple Further
The bone at the temple can become even thinner than normal in certain medical conditions. A case report described a patient with alcohol-induced liver cirrhosis who developed bilateral thinning of the squamous temporal bone, an extremely rare finding. The thinning was attributed to osteoporosis caused by the liver disease, which depleted the spongy inner layer of the skull bone called the diploë.17PubMed. Bilateral Thinning of the Temporal Bone: A Case Rep While this is an unusual presentation, it illustrates a broader principle: conditions that weaken bone throughout the body, including osteoporosis from any cause, hormonal disorders, and chronic steroid use, can disproportionately affect areas where bone is already thin. The temple is naturally the thinnest part of the skull, so it has the smallest margin of safety to begin with.
People with known bone-thinning conditions may want to discuss fall prevention with their doctors, since even a modest impact to the temple area carries outsized risk when the bone there has become paper-thin. There is no practical way to externally reinforce the temple in daily life, but awareness of the risk can inform choices about helmets during cycling or skiing and about household modifications to prevent falls.
An Evolutionary Trade-Off
You might wonder why evolution left such a critical spot so poorly armored. The answer involves trade-offs. The temporal bone’s thinness is partly a consequence of the brain’s expansion over human evolutionary history. As the brain grew larger, particularly in the temporal and frontal lobes, the skull had to accommodate that growth. Research comparing modern human skulls to those of earlier human species found that temporal lobe expansion contributed to the characteristic globular shape of the modern human skull and the retraction of the face beneath the braincase.18PubMed Central. The evolution and development of cranial form in Homo sapiens Thicker bone everywhere would have meant a heavier skull, requiring a more muscular neck, and potentially limiting the brain’s ability to grow. The temporalis muscle, which fills the temple’s depression and powers your jaw when you chew, also needed room to attach and move. A thicker temporal bone would have reduced the space available for that muscle.
So the temple’s vulnerability is, in a sense, the price paid for a larger brain and a functional jaw. The thin bone and close-running artery were not a problem for most of human evolutionary history, when lateral skull impacts at high velocity were rare. Modern life, with its vehicles, contact sports, falls from height, and interpersonal violence, has made this anatomical compromise far more consequential than it was for our ancestors walking the savanna.