Equine Vestibular Disease Study Guide

Overview and Clinical Importance

Vestibular disease in horses represents a significant category of neurological disorders affecting balance, coordination, and spatial orientation. The vestibular system is responsible for maintaining equilibrium and coordinating eye movements with head position. Dysfunction of this system produces characteristic clinical signs that are commonly tested on the NAVLE examination.

The two most common causes of vestibular disease in horses are temporohyoid osteoarthropathy (THO) and head trauma (basilar skull fractures). Understanding the anatomical basis, clinical presentation, diagnostic approach, and treatment options is essential for accurate diagnosis and effective case management.

Anatomy of the Vestibular System

Peripheral Vestibular System

The peripheral vestibular system consists of receptor organs within the inner ear and the vestibular portion of the vestibulocochlear nerve (cranial nerve VIII). The inner ear is housed within the petrous temporal bone and contains the membranous labyrinth, which is filled with endolymph.