Beyond the Growth Spurt: Do any parts of your body not grow?

October 1, 2025 •

4 min read

While the smallest bone in your body, the stapes located in your inner ear, is fully formed at birth and never grows again, this doesn't hold true for everything. The question, Do any parts of your body not grow?, reveals that while most of our anatomy continuously changes, a few surprising exceptions exist.

Quick Summary

The inner ear ossicles, eye lenses, and fully erupted teeth are fixed in size early in life. Other features, like ears and nose, only appear larger with age due to gravity and weakened cartilage, not actual growth.

Key Points

Fixed Bones: The three tiny inner ear bones, known as ossicles, are fully developed at birth and do not grow throughout life, a unique feature that ensures their function in hearing.
Eye Myths: While the eye lens is fixed in size from an early age, the eyeball itself grows significantly during childhood and adolescence, reaching full size around the early twenties.
Aging Illusion: The perception that ears and noses continuously grow with age is a myth; instead, aging and gravity cause cartilage to weaken and droop, making them appear larger.
Brain Development: The brain undergoes massive growth in the first few years, but its maturation, particularly the frontal lobe, continues into the mid-20s, allowing for ongoing cognitive development.
Dental Limits: Once permanent teeth fully erupt, they do not grow in size. Changes in jaw size during childhood make room for these larger adult teeth.
Dynamic Regeneration: Most tissues, such as skin and the liver, are in a constant state of renewal and regeneration, demonstrating the body's remarkable ability to repair and maintain itself.

The Smallest Parts That Reach Their Final Size Early

The most cited example of a body part that stops growing very early is the inner ear ossicles, the smallest bones in the human body. These three bones—the malleus (hammer), incus (anvil), and stapes (stirrup)—are fully grown at birth, reaching their adult size of a few millimeters. Their tiny, fixed size is essential for sound transmission and allows them to perform their delicate function within the confined space of the middle ear.

Another structure that follows a similar pattern is the lens of the eye. While the eye itself grows, the lens remains a fixed size. The cells of the lens continue to divide, but instead of expanding the structure, the new fibers are laid down on the surface, causing the lens to get denser and less flexible with age. This lack of growth is what leads to presbyopia, the age-related loss of near vision.

What About the Eyeball?

Contrary to a widespread myth, the eyeball is not the same size at birth as it is in adulthood. A newborn's eye is about two-thirds its final size, undergoing a significant growth spurt in the first two years of life and continuing to grow into adolescence. The perception that a baby's eyes are large is due to their disproportionately large size relative to the rest of the head at that age. By their early twenties, the eyeballs reach their full adult size, after which their length becomes stable.

Ears and Noses: Appearances Can Be Deceiving

The belief that the nose and ears never stop growing is another common misconception. While they may appear larger in older adults, this is not due to continuous growth. The effect is caused by the breakdown of cartilage and other connective tissues, combined with the relentless pull of gravity over a lifetime. This leads to the ears and nasal tip drooping and elongating, creating the illusion of growth. The cartilage itself actually stops dividing and growing after puberty.

The Dynamics of Growth and Regeneration

While some parts of the body reach a fixed size early on, most tissues and organs are in a constant state of renewal, growth, or change throughout life.

Bones continue to regenerate and remodel themselves throughout life, though overall skeletal growth typically halts around age 20 when growth plates fuse.
Skin is constantly shedding and replacing cells.
Hair and nails are made of dead cells but grow from living tissue.
The liver is a remarkable organ with a significant capacity for regeneration.


Body Part	Growth Profile	Key Characteristics
Inner Ear Ossicles	Stops growing at birth.	Fully formed at birth, smallest bones in the body.
Eye Lens	Fixed size early on.	Adds new fibers that increase density, not size, leading to presbyopia.
Teeth	Fixed size after eruption.	Baby teeth fall out and are replaced by larger permanent teeth; once erupted, size is fixed.
Eyeball	Rapid growth until early adulthood.	Reaches full adult size by the early twenties; appears large in infants due to disproportionate head size.
Ears and Nose	Cartilage stops growing after puberty.	Appear to grow in old age due to gravity and tissue degradation, causing sagging.
Bones	Grow rapidly until ~age 20.	Constantly remodeled; height may decrease slightly with age.
Skin	Continuous cell regeneration.	Outer layer is constantly shed and replaced throughout life.
Liver	Significant regenerative capacity.	Can regenerate damaged tissue and rebuild itself to its original size.

Growth Patterns of Other Key Organs

The Brain

While it is a common belief that we lose brain cells over time, the story of brain growth is more complex. The brain grows extremely rapidly in the first couple of years, reaching about 90% of its adult size by age five. However, the frontal lobe, responsible for higher cognitive functions, continues to develop into a person's mid-20s. While the number of neurons is largely fixed early on, the brain's "wiring" continues to refine and adapt throughout life through synaptic pruning and formation.

The Reproductive System

Unlike other organs that grow steadily, the reproductive organs remain largely immature until puberty. Triggered by hormones, they undergo a rapid period of growth and development during adolescence. The uterus, for example, remains small throughout childhood but has an incredible capacity for growth during pregnancy, before shrinking back to its non-pregnant size.

Conclusion

The human body is a dynamic system, but the answer to "Do any parts of your body not grow?" is yes. While many of our tissues are in a constant cycle of renewal, key structures like the inner ear ossicles, eye lenses, and fully erupted teeth reach their final size relatively early and remain fixed. Other parts, such as the ears and nose, may create the illusion of growth later in life, but this is a result of gravity and the aging process rather than true cellular expansion. Understanding these different growth profiles offers a deeper appreciation for the complex and fascinating processes that govern our bodies throughout our lives.

Frequently Asked Questions

No, this is a myth. A baby's eyeballs are only about two-thirds the size of an adult's and grow significantly in the first couple of years and during puberty, reaching their full size around age 20.

This is a common misconception. The apparent increase in size is due to the effects of aging, such as the breakdown of collagen and the effects of gravity, which cause the cartilage and skin to sag over time.

No, teeth do not grow. The baby teeth erupt first, and the jaw later grows to accommodate the larger permanent teeth, which have a fixed size once they emerge.

Yes, the three inner ear ossicles are fully formed and reach their adult size by the time a person is born. They are the smallest bones in the human body.

The brain grows extremely rapidly in early childhood, reaching about 90% of its adult size by age 5. However, its development, especially the frontal lobe, continues into the mid-20s.

The liver is a prime example of an organ with high regenerative capacity. It can repair itself and regrow lost tissue if it is damaged.

Skin is in a constant state of regeneration. New skin cells are continuously produced, while old ones are shed, maintaining the skin's surface throughout life.