Peter Huijbregts PT MSC MHSC DPT OCS MTC FAAOMPT FCAMT
Paul Vidal PT MHSC DPT OCS MTC
dizziness, vertigo, vestibular, anatomy, vascularization, physiology
Dizziness is a frequent complaint in orthopaedic physical therapy and general medical practice. It can result from dysfunctions in multiple body systems relevant to balance control. Knowledge of vestibular anatomy, vascular supply, and vestibular and visual system physiology is a necessary prerequisite for the successful clinical diagnosis and management of patients complaining of dizziness. This article discusses peripheral and central vestibular anatomy and relevant afferent and efferent pathways with emphasis on the vestibuloocular, vestibulo-spinal, and vestibulo-collic reflex circuits. The article also provides information on vestibular system vascularization and vestibular and relevant visual system physiology including a discussion of the contribution to gaze stabilization by the vestibuloocular and cervico-ocular reflex circuits, the smooth pursuit and saccadic systems, and the optokinetic response. The basic science information provided is made clinically relevant by discussing specific clinical implications for evaluation and management of patients with a main complaint of dizziness clarifying the need for comprehensive multi-system evaluation in this patient group.
Dizziness is a frequent patient complaint in orthopaedic physical therapy and general medical practice. It can result from dysfunctions in multiple body systems relevant to balance control. Proper balance control requires multi-system integration: visual, vestibular, auditory, tactile, proprioceptive, and cognitive input is integrated to produce an appropriate motor output. Extensive connections exist between the vestibular nuclear complex, the cerebellum, the ocular motor nuclei, the brainstem reticular activating system, and higher cortical centers to formulate appropriate signals for the effector organs of the balance system, i.e., the extra-ocular and skeletal muscles1. In-depth understanding of the anatomy, vascularization, and physiology of especially the vestibular system is a prerequisite to the successful differential diagnosis of patients complaining of dizziness.
The goal of this article is to provide said prerequisite knowledge by way of a review of anatomy of the vestibular system and its afferent and efferent pathways, vascularization of the vestibular system, and vestibular and relevant visual system physiology. The article will also relate this information to the clinical diagnosis and management of patients complaining of dizziness. A comprehensive discussion of anatomy and physiology of the visual, auditory, cognitive, and somatosensory systems is outside the scope of this review and we refer the reader to relevant anatomy texts for a discussion of these topics.