The lumbar interspinales are paired small muscles flanking the interspinous ligament between adjacent spinous processes. They contribute minimally to extension but, like the rotatores and intertransversarii, serve a proprioceptive function. They are encountered during interspinous process device implantation (Coflex, X-Stop) — the device replaces their position between the spinous processes.
| Origin | Superior border of each lumbar spinous process |
|---|---|
| Insertion | Inferior border of the adjacent superior spinous process — paired columns flanking the interspinous ligament |
| Nerve Supply | Medial branches of dorsal rami |
| Blood Supply | Lumbar arteries |
| Actions | Assists lumbar extension between adjacent segments; Proprioceptive monitoring of interspinous space and segmental position |
|---|
Interspinales are removed during interspinous spacer implantation procedures. Their proprioceptive function may be partially compensated by the mechanoreceptors in the interspinous ligament and supraspinous ligament after their removal.
Not palpable individually — located in the interspinous space alongside the interspinous ligament.
Interspinales involvement in Baastrup disease (kissing spinous processes) producing midline extension pain managed with interspinous injection.
