Module 9 of 12

Vestibulospinal Reflexes

Medial and lateral vestibulospinal tracts, the vestibulocollic reflex, and postural control.

While the VOR steadies the eyes, the vestibulospinal reflexes steady the body — adjusting muscle tone in the neck, trunk, and limbs to keep you upright.

The same balance organ that moves your eyes also helps you stand without falling. It sends signals down the spinal cord that tense or relax muscles in the neck, back, and legs to keep you steady.

The vestibulospinal tracts — the medial and lateral vestibulospinal tracts — integrate vestibular input with spinal proprioception to control posture. They regulate muscle tone in the neck, trunk, and limbs in response to destabilizing forces. The vestibulocollic reflex uses vestibular feedback to stabilize head position through neck muscle activation ²².

Polysynaptic connections between the vestibular nuclei and the cervical spinal cord support rapid, adaptable postural responses. These reflexes are critical for gait stability and fall prevention, especially in older adults and in patients with vestibular impairment³². Loss of vestibulospinal function contributes to the unsteadiness seen in bilateral vestibulopathy.

The medial vestibulospinal tract (MVST) projects to the cervical cord, stabilising head and neck position. The lateral vestibulospinal tract (LVST) descends the length of the cord, regulating extensor tone for trunk and limb posture against gravity.

Vestibulocollic reflex. A perturbation that tips the head triggers an opposing contraction of the sternocleidomastoid and other neck muscles, driven from the vestibular nuclei through the medial vestibulospinal tract — restoring head position within milliseconds.

Posture as an integrated output

Postural control is never vestibular alone: the vestibulospinal system blends otolith, semicircular, proprioceptive, and visual cues into a single coordinated motor output ³⁴.