The rotatores are the deepest of the transversospinalis group, spanning one or two vertebral levels in the thoracic spine. Despite their name, they are poor rotators given their short moment arm. Their high density of muscle spindles (the highest of any spinal muscle) suggests a primary proprioceptive role — monitoring and feeding back vertebral position to the CNS. They are the deepest muscles encountered in posterior spinal approaches.
| Origin | Transverse process of each thoracic vertebra |
|---|---|
| Insertion | Base of the spinous process of the vertebra one (rotatores brevis) or two (rotatores longi) levels superior |
| Nerve Supply | Medial branches of dorsal rami |
| Blood Supply | Posterior intercostal arteries |
| Actions | Rotation of the thoracic spine (primary proposed function — disputed); Proprioceptive role — high density of muscle spindles suggests a sensory rather than motor primary function |
|---|
The rotatores contain three to four times more muscle spindles per gram than the erector spinae — this extreme spindle density makes them key proprioceptors for spinal position sense. This proprioceptive function is impaired in thoracic pain syndromes and contributes to poor thoracic position awareness in kyphotic postures.
The rotatores are not palpable individually — they lie deep to all other paraspinal muscles.
Rotator spindle dysfunction in thoracic pain syndromes contributing to poor position sense managed with thoracic awareness and movement re-education.
