Muscle · Lumbar spine

Interspinales lumborum

Musculi interspinales lumborum

Short paired muscles in the low back, one on each side of the interspinous ligament, joining the spinous process of one lumbar vertebra to the next. They are well developed in the lumbar region and each spans a single joint, which puts them among the smallest and most local muscles of the spine. Sitting behind the axis of movement, directly between two bony levers, they extend one segment on the one below — but the range they can add is trivial, and their value is that they work one joint at a time in a region where most muscles cross many.