Do skulls change shape as we age? The surprising truth about craniofacial remodeling

While it's a common assumption that the adult skull is a static structure, medical science confirms that the human skull undergoes continuous and significant remodeling throughout life. The intricate process of bone resorption and deposition means that the answer to 'Do skulls change shape as we age?' is a definite yes, impacting our facial features and bone density over time.

Quick Summary

Adult skulls undergo continuous and significant remodeling, meaning they do change shape over time due to bone resorption and deposition, affecting facial features and bone density throughout life.

Key Points

• Skull Shape Isn't Static: The adult human skull continues to change shape subtly throughout life due to a process called bone remodeling.

• Bone Resorption is Key: Age-related changes are primarily driven by the imbalance between bone resorption (breakdown) and bone formation, with resorption often outpacing formation later in life.

• Facial Bones are Most Affected: The most noticeable changes occur in the facial skeleton, including the eye sockets (orbits), nasal cavity, maxilla, and mandible.

• Forehead Shows Growth: Interestingly, some areas like the forehead can experience bone deposition, while other areas like the midface and jaw experience resorption.

• Hormones and Diet Play a Role: Factors like hormonal changes (especially in women) and nutritional status can significantly influence the rate and degree of skull changes.

• Changes Contribute to Facial Aging: The alterations in the underlying bone structure, along with soft tissue changes, contribute to the appearance of an aging face, such as sunken eyes and jowls.

The Dynamic Nature of the Adult Skull

Contrary to the common belief that the adult skull is a rigid, unchangeable structure, it is actually in a constant state of flux. This process, known as bone remodeling, is a lifelong activity where old bone tissue is broken down by cells called osteoclasts and replaced with new bone tissue by osteoblasts. While this process is most active during childhood and adolescence, it never truly stops. The balance between bone resorption and formation shifts as we age, leading to notable changes in the craniofacial skeleton that contribute to the appearance of an aging face.

Understanding Bone Remodeling

Bone remodeling is a vital process that repairs micro-damage, maintains mineral homeostasis, and allows the skeleton to adapt to mechanical stresses.

• Osteoclasts: These are large, multi-nucleated cells that adhere to bone surfaces and secrete acids and enzymes to dissolve old bone tissue.
• Osteoblasts: Following resorption, these cells move into the vacated area and secrete a new bone matrix, which is later mineralized.
• Osteocytes: These are mature bone cells trapped within the bone matrix. They act as sensors, detecting mechanical stress and regulating the activity of osteoclasts and osteoblasts to maintain bone integrity.

With age, this delicate balance shifts, with resorption outpacing formation, particularly in older adults. This results in a gradual net loss of bone mass and density, including within the skull.

Where Skull Shape Changes Occur

Research using advanced imaging techniques like computed tomography (CT) has revealed specific regions of the skull that are particularly susceptible to age-related remodeling.

The Midface

One of the most noticeable areas of change is the midface. The orbits (eye sockets) and the pyriform aperture (nasal cavity opening) tend to expand with age due to bone resorption at their margins. This process can cause the eyes to appear more sunken and the nose to look longer and wider. The maxilla, or upper jawbone, also experiences anterior and inferior resorption, which can cause the midface to recede and contribute to the deepening of nasolabial folds.

The Jaw and Chin

The mandible, or lower jaw, undergoes significant changes as well. The angle of the jaw becomes more obtuse (wider) with age due to resorption, and the chin can become shorter and more oblique. The loss of teeth can accelerate these changes, leading to further atrophy of the jawbone.

The Forehead and Cranial Vault

Interestingly, not all parts of the skull experience bone loss. The forehead, or frontal bone, can actually experience bone deposition on its outer surface, particularly around the supraorbital rim, leading to a continuous expansion over time. While the overall shape of the cranial vault (the top of the skull) remains relatively stable compared to the face, studies have shown significant, though more subtle, changes occurring in its inner and outer surfaces throughout adulthood.

Factors Influencing Skull Shape Changes

Several intrinsic and extrinsic factors influence the degree and rate of skull remodeling throughout life.

• Genetics: Your genetic makeup plays a significant role in determining your craniofacial structure and how it ages. Some individuals are simply more prone to certain changes than others.
• Hormonal Changes: Hormonal shifts, particularly the decline in estrogen levels in postmenopausal women, can accelerate bone resorption and lead to more pronounced age-related changes.
• Diet: Proper nutrition, including sufficient intake of calcium and vitamin D, is crucial for maintaining bone health throughout life. Deficiencies can exacerbate age-related bone loss.
• Biomechanics: The mechanical forces exerted on the facial bones, such as those from chewing, can influence bone remodeling. Studies on medieval populations have suggested that a coarser diet may lead to a slower rate of resorptive changes in the facial skeleton.

Aging Skull vs. Aging Soft Tissues: A Comparison

To understand the full picture of facial aging, it's essential to differentiate between the changes in bone structure and the changes in soft tissues like skin, fat, and muscle.

Feature	Bone Remodeling (Hard Tissue) Changes	Soft Tissue Changes	Contribution to Aging Appearance
Midface	Resorption of bone around the eye sockets and upper jaw.	Descending fat pads, reduced collagen and elastin in skin.	Accentuated tear troughs, flattened cheeks, and deepening nasolabial folds.
Jawline	Resorption along the lower jaw, widening the jaw angle.	Loss of skin elasticity and muscle tone, causing jowls.	Sagging along the jawline and blurring of the youthful contour.
Forehead	Bone deposition, particularly near the brow ridge.	Thinning skin, loss of elasticity, and fine lines.	Fine lines, wrinkles, and changes in the brow position.
Nose	Widening of the pyriform aperture, or nasal cavity opening.	Weakening of cartilage and gravity.	Appears larger, longer, or drooping at the tip.

The Takeaway

While the changes to our skull are gradual and often unnoticed day-to-day, they play a foundational role in the overall process of facial aging. These bone changes, in conjunction with the more commonly recognized soft tissue alterations, produce the characteristic signs of advancing age.

For further reading on the complex relationship between bone health and overall aging, the National Institute on Aging provides comprehensive information on keeping your bones strong and healthy throughout your life: https://www.nia.nih.gov/health/bone-health/osteoporosis-what-you-need-know-about-it. Understanding these structural shifts can help us appreciate the full scope of the aging process and why our faces change over time.

Frequently Asked Questions

Does my face change shape with age because of my skull?

Yes, your face changes shape with age due to a combination of factors, including changes in the underlying bone structure of your skull and alterations in soft tissues like fat and muscle. As the facial bones remodel, they provide less support for overlying tissues, contributing to changes like sagging and wrinkles.

Do eye sockets change shape as you get older?

Yes, studies show that the orbits, or eye sockets, change shape with age. The orbital rims, particularly the superior and inferior parts, undergo bone resorption, causing them to widen and deepen. This can make the eyes appear more sunken or hollowed over time.

What happens to the jawbone as a person ages?

With age, the jawbone (mandible) experiences bone resorption, particularly in the angle of the jaw and the chin. This can lead to a wider jaw angle and a shorter, more oblique chin. Tooth loss can accelerate this bone loss, affecting the shape and stability of the lower face.

Can proper diet and exercise prevent skull shape changes?

While proper diet and exercise are crucial for overall bone health, they cannot entirely prevent age-related skull changes. They can, however, help to mitigate the rate of bone loss and support the body's natural remodeling processes. A diet rich in calcium and vitamin D, along with weight-bearing exercise, is beneficial for bone density.

Is it normal to notice my skull getting thicker as I age?

In some areas, yes. Research indicates that certain parts of the skull, such as the outer wall of the frontal bone (forehead), can experience bone deposition with age, leading to a thickening effect. However, other areas may experience thinning, so the changes are not uniform across the entire skull.

Do cranial sutures fuse completely and stop all changes?

While the cranial sutures, or fibrous joints of the skull, do ossify and fuse during development, the underlying process of bone remodeling continues throughout life. This microscopic renewal process, not the growth at the sutures, is responsible for the ongoing shape changes observed in the adult skull.

Can hormonal changes cause significant facial bone changes?

Yes, hormonal changes, particularly in women during and after menopause, can have a significant impact on bone remodeling. The decline in estrogen can accelerate bone resorption throughout the skeleton, including the facial bones, contributing to more pronounced age-related changes in shape.