Human Movement Science & Functional Anatomy of the:

Rotatores, Interspinales and Intertransversarii

by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

 

Rotatores

  • Origin: Transverse processes of vertebrae at all levels (3)
  • Insertion: Base of the spinous process and adjacent lamenae.  The fibers spanning one segment may be referred to as short rotatores or rotatores brevis.  The fibers spanning 2 segments may be referred to as long rotatores or rotatores longus (3).
    • The rotatores are deep to the multifidus; lying between and adjacent (lateral) to vertebral facets.  (The multifidus fill the vertebral arch between spinous and transverse process, lying on top (posterior) the facet joints.)  The rotatores muscles are enveloped by the deepest and most medial layer of spinal fascia that extends from spinous process to transverse process in cross section.  The multifidus and interspinales are also enclosed within this compartment.
      • It is unlikely that the rotatores can be deferentially palpated.  However, when a "nodule" is palpated in the trough between spinous and transverse process, adjacent to a dysfunctional spinal segment, it may be over-activity and increased tissue density (trigger or tender points) within fascicles of the rotatores and multifidus.
  • Nerve: Segmentally innervated by dorsal rami of adjacent spinal nerves (3).
  • Action:
    • Extension, ipsilateral flexion, and contralateral rotation (although the cross-sectional area, small moment arm, and length imply little if any contribution to motion.)
    • Segmental (vertebrae on vertebrae) stabilization.
    • Based on a study by Nitz and Peck (15), these muscles exhibit 4.5 to 7.3 times the muscle spindle density of the multifidus, implying greater contribution to position sense, proprioception, and a role in reflexive facilitation, and/or inhibition of larger and more superficial spinal and trunk musculature (13, 15).

Interspinales

  • Origin: These muscles extend between adjacent spinous processes in the cervical spine (below C2), often the extreme upper and lower regions of the thoracic spine, and the lumbar spine.  Note these muscles are not present between mid-thoracic segments.
    • The interspinales are embedded in a complex fascial network that includes the supraspinous ligament, interspinous ligament, the ligamentum nuchae in the cervical spine, and encased within the same fascial envelope that surrounds the multifidus and rotatores.  It is not possible to palpate this musculature, and their position and surrounding fascial network has posed a challenge to safe, effective and consistent EMG analysis.
  • Nerve: Segmentally innervated by dorsal rami of adjacent spinal nerves
  • Action:
    • Extension (although the cross-sectional area, small moment arm, and length imply little if any contribution to motion.)
    • Segmental (vertebrae on vertebrae) stabilization.
    • It has been proposed by McGill that these muscles may serve a similar role to the rotatores in position sense, proprioception and reflexive facilitation.

 

Intertransversarii (Intertransversarius)

  • Origin and Insertion: These muscles extend between adjacent transverse processes in the cervical spine, lower thoracic spine, and all lumbar vertebrae.  The cervical region is subdivi

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