BIOPHYSICS OF POSTURE AND MASTICATORY MUSCLES: HOW SPINAL ALIGNMENT AFFECTS FACIAL FORM AND HEALTH

БИОФИЗИКА ОСАНКИ И ЖЕВАТЕЛЬНЫХ МЫШЦ: КАК ВЫРАВНИВАНИЕ ПОЗВОНОЧНИКА ВЛИЯЕТ НА ФОРМУ ЛИЦА И ЗДОРОВЬЕ

Кундулдаев Шакарим

студент, Школа медицины, Казахский национальный медицинский университет имени С. Д. Асфендиярова,

Казахстан, Алматы

Исак Нурдаулет

студент, Школа медицины, Казахский национальный медицинский университет имени С. Д. Асфендиярова,

Казахстан, Алматы

Абдрасилова Венера

научный руководитель, и.о. доц. кафедры нормальной физиологии с курсом биофизики, Казахский национальный медицинский университет имени С. Д. Асфендиярова,

Казахстан, Алматы

ABSTRACT

Posture is an important biomechanical factor influencing the function of both the musculoskeletal and craniofacial systems. The alignment of the spine, especially in the cervical region, is closely related to mandibular position, the activity of the masticatory muscles, and the development of facial structures. Modern lifestyle habits, including prolonged sitting and intensive use of digital devices, contribute to postural disorders such as forward head posture. These changes may disrupt neuromuscular balance, affect temporomandibular joint function, and influence facial growth patterns. This article analyzes the biophysical relationship between posture and the masticatory system, explains the main underlying mechanisms, and discusses their practical significance for health and prevention.

АННОТАЦИЯ

Осанка является важным биомеханическим фактором, влияющим на работу опорно-двигательной и челюстно-лицевой систем. Положение позвоночника, особенно в шейном отделе, тесно связано с положением нижней челюсти, активностью жевательных мышц и формированием лицевых структур. Современный образ жизни, характеризующийся длительным сидением и активным использованием цифровых устройств, способствует развитию постуральных нарушений, в частности выдвинутого положения головы вперёд. Эти изменения могут нарушать нейромышечный баланс, влиять на функцию височно-нижнечелюстного сустава и изменять процессы роста лица. В статье рассматривается биофизическая взаимосвязь между осанкой и жевательной системой, объясняются основные механизмы и практическое значение для здоровья.

Keywords: posture; spinal alignment; masticatory muscles; temporomandibular joint; craniofacial development; biomechanics; forward head posture.

Ключевые слова: осанка; положение позвоночника; жевательные мышцы; височно-нижнечелюстной сустав; развитие лица; биомеханика; выдвинутая голова вперёд.

Introduction

In recent decades, posture disorders have become increasingly common. This trend is largely associated with sedentary lifestyles, long hours spent at computers, and extensive use of smartphones. One of the most typical postural deviations is forward head posture, a condition in which the head is positioned anteriorly relative to the shoulders. Although posture is traditionally discussed in the context of back or neck pain, its influence extends beyond the spinal column. The craniofacial region, including the jaws, teeth, and masticatory muscles, is functionally connected with the cervical spine. The position of the head determines the spatial orientation of the mandible and affects the loading conditions of the temporomandibular joint (TMJ). According to Solow and Sandham (2002), cranio-cervical posture plays a significant role in the development and function of dentofacial structures. Therefore, postural imbalances may influence facial structure, muscle tone, occlusion, and even breathing patterns. Understanding these interactions is especially relevant for students and professionals in medicine, dentistry, and physiotherapy, as it supports a more integrated approach to prevention and treatment.

Key Concepts

Posture

Posture can be described as the position of the body in space that is maintained by coordinated muscle activity and neural regulation. It reflects the balance between gravitational forces and muscular support. In clinical practice, posture is considered an indicator of both musculoskeletal health and functional efficiency.

Spinal Alignment

Spinal alignment refers to the natural curvatures of the vertebral column, including cervical lordosis, thoracic kyphosis, and lumbar lordosis. These curves help distribute mechanical loads and maintain balance during movement and rest. Disturbances in one part of the spine often lead to compensatory changes in adjacent regions.

Masticatory Muscles and TMJ

The masticatory muscles are responsible for movements of the mandible during chewing and speech. The main muscles involved are the masseter, temporalis, and the medial and lateral pterygoids. Their coordinated activity ensures efficient jaw function. The temporomandibular joint connects the mandible to the temporal bone of the skull. It allows movements such as opening, closing, protrusion, and lateral deviation of the jaw. According to Okeson (2019), the TMJ is highly sensitive to changes in muscle tone and head posture.

Biomechanical Mechanisms of Interaction

Influence of Head Position on Jaw Alignment

The human head weighs approximately 4–6 kilograms. In a neutral posture, it is balanced over the cervical spine, which minimizes muscular effort. However, in forward head posture, this balance is disturbed. As the head moves forward, the cervical spine gradually loses its natural curvature. In response, the mandible tends to rotate downward and backward. This shift alters the loading conditions within the temporomandibular joint and increases the activity of the masticatory muscles. Studies have shown that such changes are associated with elevated muscle tension and uneven joint loading (Cuccia & Caradonna, 2009). These mechanisms suggest that even moderate postural deviations may have functional consequences for the masticatory system over time.

Neuromuscular Connections

The masticatory and cervical muscles are interconnected through shared neural pathways in the brainstem. There is also reflex coordination between the jaw and neck muscles during chewing, swallowing, and speech. For example, activation of jaw-closing muscles is often accompanied by stabilization of the cervical spine. This indicates that the two systems operate as a functional unit rather than as independent structures. As a result, disturbances in cervical muscle balance may influence jaw function and vice versa.

Muscle Chain Concept

The body functions through interconnected muscle chains. The anterior chain includes the cervical flexors, the suprahyoid and infrahyoid muscles, the tongue muscles, and the masticatory muscles. Changes in one part of this chain can influence the entire system. For instance, shortening of the neck flexors may alter tongue posture. In turn, tongue position affects the development of the dental arches, which ultimately influences facial structure. This interconnectedness highlights the importance of considering posture when evaluating craniofacial conditions.

Influence on Facial Growth

In children and adolescents, bone structures are still developing. Mechanical forces generated by muscles and posture play an important role in shaping the face. According to the functional matrix theory described by Proffit et al. (2018), bone growth is largely guided by functional demands and surrounding soft tissues. Continuous muscle tension can lead to gradual changes in bone shape and orientation, a process known as bone remodeling. If postural disorders persist, they may contribute to narrowing of the dental arches, mandibular retrusion, elongation of the facial profile, and different types of malocclusion. These observations suggest that posture should be considered as one of the contributing factors in craniofacial development, especially during growth periods.

Practical Significance

Temporomandibular Disorders

Temporomandibular disorders (TMD) involve dysfunction of the TMJ and the masticatory muscles. Common symptoms include jaw pain, clicking sounds, limited mouth opening, and headaches. Research indicates that forward head posture is associated with increased activity of the masseter and temporalis muscles and a higher prevalence of TMD symptoms (Okeson, 2019; Cuccia & Caradonna, 2009). This relationship suggests that correcting posture may help reduce muscle tension and improve joint function.

Orthodontic Treatment

Orthodontic treatment aims to correct tooth alignment and jaw relationships. However, if underlying postural issues are not addressed, treatment results may become unstable over time. In some cases, malocclusion may recur or facial asymmetry may persist. Modern orthodontics increasingly considers factors such as head and neck posture, tongue position, breathing patterns, and muscular balance. This reflects a more comprehensive understanding of craniofacial development.

Breathing and Speech

Posture also affects respiration, voice production, and swallowing patterns. Forward head posture may reduce airway space, promote mouth breathing, and alter tongue position. These changes can influence both breathing efficiency and speech articulation. From a functional perspective, this highlights the importance of maintaining proper posture not only for musculoskeletal health but also for optimal respiratory and speech function.

Conclusion

The relationship between posture and the masticatory system illustrates the integrated nature of the human body. Spinal alignment, particularly in the cervical region, directly influences jaw position, muscle activity, and temporomandibular joint function. Forward head posture may alter mandibular alignment, increase muscle tension, and contribute to temporomandibular disorders. In growing individuals, postural imbalances can also affect facial development through bone remodeling and functional adaptation. These findings support the idea that posture should be considered an important factor in both prevention and treatment strategies. Interdisciplinary approaches involving dentistry, physiotherapy, and ergonomics appear to be the most effective way to address these complex interactions.

References:

1. Cuccia, A. M., Caradonna, C. The relationship between the stomatognathic system and body posture. Clinics, 2009.
2. Kendall, F. P., McCreary, E. K., Provance, P. G. Muscles: Testing and Function with Posture and Pain. Lippincott Williams & Wilkins, 2005.
3. Okeson, J. P. Management of Temporomandibular Disorders and Occlusion. Elsevier, 2019. Proffit, W. R., Fields, H. W., Sarver, D. M. Contemporary Orthodontics. Elsevier, 2018.
4. Solow, B., Sandham, A. Cranio-cervical posture: a factor in the development and function of the dentofacial structures. European Journal of Orthodontics, 2002