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With the continuous evolution of humans, it is common to hear one ask, “How thick is a human skull?”
The human skull serves as a protective casing for the brain and other vital organs while supporting our facial features.
One intriguing aspect of the skull that often piques curiosity is its thickness and the factors influencing its thickness.
If you’re interested in learning more about the human skull, there’s no shortage of information available. Read to the end to learn more.
So, How Thick Is A Human Skull?
The average skull thickness of an adult is 6.5 to 7 millimeters. Men have a frontal thickness averaging 7.8mm, parietal thickness of 9.6mm, occipital thickness of 10.1mm, and temporal thickness of 6mm.
For women, the frontal averages 8.6mm, the parietal is 10.1mm, the occipital is 10mm, and the temporal is 6mm.
How Is The Skull Thickness Measures?
Measurement of skull thickness is an essential part of the development of medical technology and forensic investigations. Additionally, measuring skull thickness is crucial in understanding cranium developments and adaptations.
1. Computer Tomography Scan
A computer tomography scan is commonly known as a CT scan, and doctors widely use it for precise and accurate measurements of skull thickness.
The non-invasive imaging technique offers a detailed cross-sectional image of the skull, allowing one to measure the specific regions that interest them.
Integrated and specialized software can help take measurements of various aspects of the human skull, such as the inner and outer surfaces of the skull bone.
2. Ultrasonography
It’s a unique technique that utilizes high-frequency sound waves to create images of body tissues. It can be employed to measure skull thickness in infants or children. Ultrasonography offers real-time non-invasive measurements of the skull bone thickness.
3. Ruler And Calipers
In some instances, one can use a ruler or caliper to measure the thickness of a skull. These instruments are useful, especially when dealing with ancient fossils from the ground. However, the measurement method is more prone to errors than advanced imaging techniques.
4. Anthropological Techniques
Anthropologists often use craniometrical methods to understand skull morphology, including its thickness better. It involves taking physical measurements of cranial vault thickness using calipers and other physical tools.
They use most of these measurements to conduct a comparative analysis among different populations.
5. Virtual 3D Reconstruction
The advancement of technology has led to the rise of new ways of taking measurements. Virtual 3D reconstruction of skulls can be possible through computer software based on CT or MRI scans.
Through the 3D models, we can take accurate measurements of skull thickness. The best thing about using software tools is that they can recreate the CT scan of multiple people, increasing the database of the research.
Additionally, it reduces the time taken to comprehend a measurement, allowing the completion of more work over a shorter period.
Anatomy Of The Human Skull
The human skull has twenty-two outer bones, and seven inner bones joined together by ossified joints (sutures) to form the protective layer for the brain.
It consists of the facial skeleton and brain case. Here’s an overview of the major components that form the human skull:
Facial Bones
The facial bones of the skull are responsible for forming the framework of the face and offer support to sensory organs. Facial bones include:
- Lower jaw (mandibles)
- Upper jaw (maxilla),
- Cheekbones (zygomatic bones)
- Palatine bone (at the mouth roof)
Lacrymal bones are found near the eye and inside the nasal cavity, and we have vomer bones inside the nasal cavity.
Cranium
The skull encloses and protects the brain against injuries. It consists of a few bones, which include:
- Parietal bone (found at the side of the head),
- Temporal bones (sides and base of skull),
- Occipital bone (back of the head)
- Sphenoid bone (central base of the skull)
- Frontal bone (forehead)
- And ethmoid bone (between the eyes)
These bones are interconnected to shield the brain from external harm.
Sutures
Sutures are important bones that allow slight movement of cranial bones during childbirth. It also allows flexibility in the growth of the brains of children. They are also essential gateways for conducting brain surgery.
- Sagittal suture (between parietal bones)
- Coronal suture (between frontal and parietal bones)
- Lambdoid suture (between occipital and parietal bones)
- Squamous Suture (between the temporal and parietal bones)
Foramina
Foramina consists of small openings in the brain that allow passage of blood vessels, nerves, and other structures essential for brain functioning. Other foramina allow passage of cranial nerves at the base of the skull.
- Foramen magnum- Allows passage of the spinal cord
- Optic foramina- Allows passage of optic nerves to the eye
Sinuses
The skull also has cavities filled with air called sinuses. They include:
- Frontal sinuses (found in the forehead)
- Ethmoid sinuses ( between the eyes)
- Sphenoid sinus (at the base of the skull)
- Maxillary sinuses (in the cheekbone)
Factors Influencing Skull Thickness
Several factors influence the thickness of the skull, and scientific research has shed light on some, which we will discuss in this section.
Age
Researchers have noted that skull thickness increases during childhood and adolescence, reaching its peak in early adulthood. Later on, as adults grow older, the thickness of their skulls tends to decrease.
The age-related variation in the thickness of the human skull is attributed to the non-ending bone remodeling processes throughout a person’s life. One notable research study investigated age’s influence on skull thickness in 2016.
The study aimed to examine the age-related changes in skull thickness and bone mineral density in healthy Chinese adults. The study results indicated a clear association between age and skull thickness.
Sex
Several studies have observed differences in skull thickness between males and females. The research done by researchers suggests that males generally have thicker skulls compared to females.
It may be related to sexual dimorphism and the difference in hormonal influence on bone density and structure. A notable difference has been observed, especially in the frontal bones of the two genders.
Some females also have larger skulls than males, but on average, men’s skulls are thicker than those of females.
Geographical Location
Studies examining different skull thicknesses across multiple ethnic groups and geographical regions have shown some variations.
For instance, African ancestry has been found to exhibit thicker cranial bones compared to individuals of European ancestry. The differences in thickness in the skull are genetic, environmental, and evolutionary factors.
Genetics
Genetics is another important factor that plays a role in determining skull thickness. Several genes related to bone density and development directly contribute to different individuals’ skull thickness variations.
The study of genetics has highlighted specific gene variants responsible for skull morphology and thickness.
Adaptations And Significance Of Skull Thickness
The thickness of the human skull is subject to essential adaptations and holds significant functional importance. Some of the adaptations and significance related to skull thickness include:
1. Brain Protection
Protection of the brain from external forces is the primary function of the thickness of the skull. The thick bones that make up the skull are a protective barrier that absorbs and distribute impact that could harm the delicate brain tissues.
2. Mechanical Stability
The human skull skulls thickness dramatically contributes to the mechanical stability of the head and face.
It offers structural support for muscle and ligament attachment responsible for head movements, chewing, and facial expressions.
Skull thickness helps to maintain proper coordination and alignment of these movements enhancing their functional efficiency.
3. Thermal Regulation
Humans are warm-blooded, implying that their body temperature needs to be kept optimum constantly for proper functionality.
The thickness of the human skull also plays a role in thermal regulation. The insulating properties of thicker cranial bones help regulate the brain’s temperature and generally preserve heat around the body.
It is even more significant within areas with extreme climatic conditions where stable brain temperature is crucial for optimal functioning.
4. Environmental Adaptation
The thickness of the human skull can exhibit variations depending on the adaptations to different environmental factors.
A population living in an environment that experiences a lot of trauma and harsh climatic conditions might have a thicker skull as an adaptive response to increase protection. The thick craniums help mitigate the impact of external forces and environmental stress.
5. Individual Variation
Some individual variations, such as sex and genetics, can influence the thickness of the human skull. Genetic factors will influence individuals’ inheritable variation in skull thickness, while sex differences may lead to variation in skull differences between males and females.
Conclusion
The question of how thick is a human skull reveals the fascinating intricacies of cranial anatomy and highlights the remarkable adaptability of the structure. By exploring skull thickness, we can realize a world of fascinating variations and protective mechanisms.
Unraveling the mysteries of the human skull helps us understand our evolutionary changes and better appreciate our knowledge. The human skull protects our most prized possession, our brain, which is essential for our evolutionary survival.
