The Navicular Bone: A Keystone for Foot Mechanics and Whole-Body Health

What is the most remarkable human thing on the planet?

Is it our oversized brains for our bodies? Is it that we have terraformed the planet and our homes to be more hospitable for our furless bodies? Or is it the art, cities, and sciences our brains and society have created?
The most human thing on the planet is our feet and how it allows us to be bipedal. The anatomy that makes that possible is our straight big toe and our 3 arches of the foot, of which the navicular bone is the keystone of the medial arch.

The navicular bone, a small yet significant component of the human foot, plays a crucial role in foot mechanics and overall body health. This unique bone, nestled within the medial longitudinal arch, has been instrumental in developing human bipedalism - one of our most distinguishing traits as a species.

Bipedalism relies heavily on the structural adaptations of our feet, which are markedly different from those of our closest relatives, the great apes. While ape feet are characterized by a flexible, grasping structure that aids in climbing and knuckle-walking, the human foot has evolved a robust, stable arch that efficiently supports our weight during upright walking and running.

The navicular bone is a keystone for this arch, providing critical support and stability for efficient bipedal locomotion. As we explore the importance of the navicular bone in foot mechanics, we will also examine its impact on overall body health and the interconnectedness of the human musculoskeletal system.

Anatomy of the Navicular Bone

The navicular bone, situated in the medial aspect of the foot, plays a pivotal role in the evolution of human bipedalism, setting us apart from our primate relatives. Unlike the flexible and versatile feet of apes, designed for grasping branches and knuckle-walking, the human foot has developed a more rigid and supportive structure that allows for efficient bipedal locomotion. Central to this functional transformation is the navicular bone, which is nestled between the talus and the three cuneiform bones, acting as a critical junction in the tarsal structure. This small, boat-shaped bone is a keystone for the medial longitudinal arch, connecting to surrounding structures such as the plantar fascia, spring ligament, and posterior tibial tendon. These connections contribute to the stability and support of the arch but also help maintain the biomechanical integrity of the foot, ultimately facilitating the evolution of bipedalism as a defining human trait.

Mechanics of the Foot and the Role of the Navicular Bone

The medial longitudinal arch, a vital component of the human foot, has evolved to facilitate effective bipedal locomotion by providing shock absorption, load distribution, and energy return during walking and running. This arch starkly contrasts the more flexible foot structure of apes, which is designed for grasping and arboreal movement. At the core of the medial longitudinal arch's Function is the navicular bone, which serves as a keystone, ensuring the stability and integrity of the arch. This crucial role of the navicular bone supports our ability to walk upright and distinguishes us from our primate counterparts. However, dysfunction of the navicular bone can lead to a cascade of biomechanical issues, such as fallen arches or overpronation, which can compromise the foot's ability to effectively support and propel the body during bipedal movement. Understanding the role of the navicular bone in maintaining proper foot mechanics is essential for recognizing its significance in developing and preserving one of humanity's most defining traits—bipedalism.

Consequences of Navicular Dysfunction

The significance of the navicular bone in supporting bipedalism and maintaining proper foot mechanics becomes particularly evident when dysfunction arises. Navicular dysfunction can lead to various conditions, such as navicular stress fractures or posterior tibial tendon dysfunction, which may cause pain, instability, and altered gait patterns. However, the repercussions of these issues are not limited to the foot alone. Altered foot mechanics resulting from navicular dysfunction can disrupt the kinetic chain, propagating imbalances and compensations throughout the lower extremity, pelvis, and spine. This ripple effect highlights the interconnectedness of the human musculoskeletal system and underscores the importance of maintaining the functional integrity of the navicular bone. By contrast, the foot structure of apes, with its inherent flexibility and adaptability, may not exhibit the same degree of mechanical vulnerability. The unique role of the navicular bone in human foot mechanics and bipedalism, therefore, necessitates a thorough understanding of its potential impact on overall body health and Function.
V. Chiropractic Approaches for Navicular Dysfunction

As the navicular bone is instrumental in bipedalism and overall body health, it is essential for healthcare professionals, particularly chiropractors, to effectively identify and address navicular dysfunction. Various assessment techniques, such as manual palpation and gait analysis, can be employed to pinpoint biomechanical issues stemming from navicular dysfunction. Chiropractic treatments, including manipulation, mobilization, and orthotics, can help restore proper foot mechanics and alleviate discomfort associated with this dysfunction. While the foot structure of apes is inherently different from that of humans, the unique role of the navicular bone in human foot mechanics necessitates a comprehensive understanding of its Function and potential implications. Collaboration with other healthcare professionals, such as podiatrists and physical therapists, is crucial to ensure a holistic and multidisciplinary approach to managing and preventing navicular dysfunction and its impact on bipedalism and overall body health. This collaborative effort highlights the importance of considering the navicular bone in the broader human biomechanics and well-being context.

Prevention and Self-Care Tips

The unique role of the navicular bone in human bipedalism and foot mechanics highlights the importance of taking proactive measures to maintain its Function and prevent dysfunction. Proper footwear and minimalist shoe are crucial for preserving optimal foot mechanics, as they provide a stable foundation for the navicular bone and the medial longitudinal arch.

Minimalist wide-toe box shoes offer many benefits, particularly in foot strength and navicular function. By providing ample space for the toes to spread naturally, these shoes encourage proper foot alignment and allow the muscles to work more effectively. This, in turn, can help strengthen the foot's intrinsic muscles, leading to improved stability, balance, and overall foot health. Furthermore, the minimalist design of these shoes facilitates better ground feedback, enabling the wearer to develop a more efficient and natural gait pattern. This can lead to reduced strain on the lower extremities and a decreased risk of injury.

One of the critical benefits of minimalist wide-toe box shoes is their impact on navicular function. The navicular bone in the midfoot region plays a vital role in maintaining the medial longitudinal arch. Wearing shoes with a wide toe box allows the navicular bone to maintain its optimal position, supporting proper arch function. This can help prevent issues like flat feet or overpronation, often associated with more traditional, narrow shoes. By promoting healthy foot mechanics and supporting the navicular bone, minimalist wide-toe box shoes offer a comfortable and functional alternative that encourages long-term foot health and improved biomechanics.

By contrast, the foot structure of apes is inherently more adaptable, with less reliance on external support. For humans, incorporating foot strengthening exercises into one's routine can help maintain arch stability and promote healthy biomechanics, further safeguarding against navicular dysfunction.

Regular chiropractic care also plays a vital role in preserving foot and overall body health, as it can address biomechanical imbalances before they lead to dysfunction or injury. By prioritizing prevention and self-care, individuals can better support the Function of the navicular bone, ensuring the continued efficiency of bipedal locomotion and overall musculoskeletal health.

As for the chiropractic and AK perspective of navicular dysfunction, most of the time the navicular bone will drop or subluxate inferiorly, this usually results in an inhibition of the posterior tibialis muscle.  

Conclusion

The navicular bone, a critical component of the human foot, has played a crucial role in the evolution of bipedalism, distinguishing us from our primate relatives. While ape feet are designed for grasping and arboreal movement, the human foot has developed a stable arch, with the navicular bone acting as its keystone, facilitating efficient bipedal locomotion. Understanding the importance of the navicular bone for foot mechanics and whole-body health is crucial, as dysfunction can lead to a cascade of biomechanical issues affecting the foot and the entire kinetic chain. Chiropractic care is invaluable in managing and preventing navicular dysfunction and related conditions, as it addresses biomechanical imbalances and promotes optimal musculoskeletal Function. By recognizing the unique role of the navicular bone in human foot mechanics and bipedalism, individuals and healthcare professionals can better appreciate the significance of maintaining its functional integrity for overall health and well-being.