Brain Neurorehabil.  2013 Sep;6(2):47-53. 10.12786/bn.2013.6.2.47.

Anatomy and Physiology of Balance

• Im S

• KMID: 1797945
• DOI: http://doi.org/10.12786/bn.2013.6.2.47

Abstract

Postural balance is controlled by intricate connections between the vestibular, visual and proprioception system. Among these, the vestibular system is one of the key factors in coordinating and maintaining balance. The peripheral apparatus for the vestibular system consists of the semicircular canals, which sense head rotation; and the otoliths, which sense gravity and linear acceleration. The central vestibular pathways form a large network from the vestibular nuclei, ocular motor nuclei, integration centers in the pons and rostral midbrain, vestibulocerebellum, thalamus, to the multisensory vestibular cortex areas in the temporoparietal cortex. The most important structures for the central vestibular pathways are those mediating the vestibulo-ocular reflex (VOR), and the descending pathways into the spinal cord along the medial and lateral vestibulospinal tract which mediate postural control. The cortical structures involved in vestibular function are the parietoinsular vestibular cortex, the retroinsular cortex, the superior temporal gyrus and the inferior parietal lobule. Activation of the cortical network during vestibular stimulation is not symmetrical; dominance is stronger in the nondominant hemisphere, in the hemisphere ipsilateral to the stimulated ear and in the hemisphere ipsilateral to the slow phase of the vestibular caloric nystagmus. Disorder of the vestibular pathway, anyway along its various tracts, may result in balance and coordination impairments and lead to misperception of motion.

Keyword

cerebellum; postural balance; proprioception; vestibular; vestibulo-ocular reflex

MeSH Terms

Acceleration
Ataxia
Cerebellum
Ear
Gravitation
Head
Mesencephalon
Negotiating
Nystagmus, Physiologic
Otolithic Membrane
Pons
Postural Balance
Proprioception
Reflex, Vestibulo-Ocular
Semicircular Canals
Spinal Cord
Thalamus
Vestibular Nuclei

Figure

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  Fig. 1 Lateral view of the right human labyrinth (adapted from Hardy 1934).

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  Fig. 2 Schematic drawing of the semicircular canal showing the ampulla and cupula.

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  Fig. 3 Diagram showing the various connections of the vestibular nuclei (modified from Lundy-Ekman 2012).

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  Fig. 4 Schematic drawing showing the neural structures involved in the vestibulo-ocular reflex (adapted from Dieterich 2007).

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  Fig. 5 Illustration showing cortical activation during vestibular stimulation. Activations in the temporo-parieto-insular areas of both sides are observed with dominance of the non-dominant right hemisphere. During vestibular stimulation, deactivations are observed in the visual cortex bilaterally (adapted from Dieterich 2010).

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  Fig. 6 Schematic drawing showing the vascular territories of the cerebellum (modified from Lundy-Ekman 2012).

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