Rotatores and Multifidi – Functional Anatomy

Rotatores are the deepest muscles in the lamina groove. Rotatores connect the transverse process of a vertebra to the spinous processes of the two vertebrae just above it.

Multifidi lay just on top of the rotatores.  Multifidi connect from the transverse process of a vertebra to the spinous processes of the vertebrae 3-5 segments higher trapping vertebrae between the attachments.

They, in combination with the rotatores, are seen as stabilizing vertebrae in relation to the 5 or 6 vertebrae above it.

Rotatores lay under the multifidi, and semispinalis muscles lay above the multifidi, but the bulk of muscle in the lamina groove is made of the multifidi.

They are innervated by the posterior rami of spinal nerves.

Cervical:

Origin – articular process (of the lower four vertebrae)

Insertion – transverse process of the vertebrae 2-4 segments above, up to the axis

There are exceptions to the typical multifidi structure, and cervical multifidi are included. They originate on C5-C7 and insert on C2-C5, leaving some with single strands that only skip over one vertebra.

Thoracic:

Origin – transverse process

Insertion – the spinous process of the vertebrae 3-5 vertebrae above the origin

Lumbar:

Origin – mamillary process

Insertion – spinous process of the vertebrae 3-5 segments above the origin

The lumbar multifidi form a thick pillar of muscle on in the low back. They continue onto the sacrum to the

Studies report that the lumbosacral multifidi, especially below L3, atrophy much faster than most muscles with age, starting in the late 30s.