Muscle:Rotadores
Rotatores are the deepest layer of the paraspinal muscles and the shortest of the deep paraspinal group. They produce midline pain and referred tenderness on tapping the spinous process adjacent to a TrP. Involvement throughout the length of the thoracolumbar spine produces midline pain centering on the spinous processes at the segmental level of the TrP, or in the lumbar region, it may be referred a few segments caudally. The rotatores are believed to function primarily as dynamic ligaments for fine adjustments between individual vertebrae, acting as spinal position sensors, rather than as prime movers of the vertebral column as a whole. TrPs in the rotatores can induce a concurrent single-level articular dysfunction — the most segmentally specific of all the paraspinal muscles.
Anatomy
The short rotatores attach to adjacent vertebrae. The long rotatores span one segment throughout the spine but ordinarily do not include sacral segments.
The rotatores form the deepest layer at both the thoracic and lumbar levels. They occur above the sacral level. Only the multifidi extend across sacral segments. The multifidi and rotatores muscles continue beyond the lumbosacral junction where they fill the multifidus triangle of the sacrum and are covered by the tendinous extensions of the more superficial longissimus and iliocostalis muscles.
The deeper multifidi and rotatores muscles attach medially and above near the base of a vertebral spinous process; laterally and below they attach to a transverse process. As the fibres of the progressively deeper muscles become progressively shorter and more horizontal, they increasingly rotate the spine rather than primarily extending it.
Primary action: Bilateral contraction extends the vertebral column; unilateral contraction rotates the vertebrae to the contralateral side. Based on EMG evidence, the rotatores (deepest transversospinal muscles) act as dynamic ligaments that adjust small movements between individual vertebrae, functioning primarily as position sensors for fine adjustments rather than as gross movers.
Innervation: Medial branches of the dorsal primary divisions (rami) of the corresponding spinal nerves. In the lower thoracic and lumbar regions, the nerve, the rotator muscle, and the tip of the spinous process which has the same number as the nerve are all at the same level.
Referred Pain Pattern
Involvement of the rotatores throughout the length of the thoracolumbar spine produces midline pain and referred tenderness on tapping the spinous process at the segmental level of the TrP. The pain centres primarily on the spinous processes of the vertebra adjacent to the TrP. In the lumbar region, pain may be referred a few segments caudally.
This spinous process tenderness from rotatores or multifidus involvement:
- Is easily located by tapping each spinous process in succession
- Disappears after inactivation of the responsible TrPs, which may be located on either or both sides of the spine
- Is used as an osteopathic sign of articular-dysfunction involvement of that vertebra
Only deep palpation of the muscles can determine from which side the midline pain arises.
Symptoms
The severe aching "bone" pain from TrPs in the deep paraspinal group is persistent, worrisome, and disabling. When the complaint of "lumbago" is due to TrPs in the deep lumbar paraspinal muscles, the pain is a unilateral, extremely disagreeable, steady ache deep in the spine. It becomes bilateral as the muscles on both sides become involved. The patient finds little relief by changing position and is often convinced the pain originates in the bony spine rather than the muscles.
Articular Dysfunction Association
TrPs in the rotatores can induce a concurrent single-level articular dysfunction — the most segmentally specific articular effect of all the paraspinal muscles:
- Rotatores → single-level dysfunction
- Multifidi → two to three adjacent segmental levels
- Semispinalis → four to six segmental levels
This segmental specificity makes the rotatores clinically important for identifying the exact vertebral level of articular dysfunction.
Activation and Perpetuating Factors
Same as for the superficial paraspinal group — see Muscle:Iliocostalis Thoracis for full details. The deep group is more likely to show isolated muscle involvement (single-level), whereas the more superficial paraspinal muscles are likely to accumulate associated TrPs in functionally related muscles, especially the contralateral superficial muscles.
Nerve Root Compression
The muscles supplied by a compressed nerve root or any cause of mild entrapment neuropathy are likely to develop TrPs. Myofascial TrPs per se do not cause neurological deficits unless the TrP taut band entraps a peripheral nerve. The number of specific muscle-nerve entrapment syndromes is limited, and the degree of nerve damage is rarely more than neuropraxia.
Clinical Examination
Deep Paraspinal Palpation Technique
Active TrPs in the deep paraspinal muscles are identified by eliciting focal deep tenderness and noting the resulting referred pain pattern. Deep paraspinal TrPs are specifically identified by:
- Patient recumbent or seated and leaning forward to flex the spine slightly
- A flattened region or slight hollow extending over one to three vertebrae indicates the probable TrP source
- Examiner taps or presses on the tips of successive spinous processes
- When a spinous process in the flat area is hypersensitive, the deep musculature on each side is palpated by firm pressure in the groove between the process and the longissimus muscle
- Deep finger pressure is directed along the side of the spinous process to exert pressure on the rotatores against the underlying laminae, to locate a spot of maximum tenderness
- If two or three spinous processes are tender, adjacent TrPs are expected on at least one side at each level of tenderness
Distinguishing the Source of Midline Pain
Only deep palpation of the muscles can determine from which side the midline pain arises. This spine tenderness disappears after inactivation of the responsible TrPs.
Differential Diagnosis
| Condition | Distinguishing features |
|---|---|
| Interspinous ligament strain | Midline spinous process tenderness from rotatores TrPs may mimic interspinous ligament strain; distinguished by deep palpation locating the TrP lateral to the spinous process; TrP inactivation resolves spinous tenderness |
| Spinal fracture / metastasis | Persistent midline spine tenderness requires imaging to exclude fracture or metastatic disease if the clinical context warrants; myofascial TrP pain disappears after TrP inactivation; structural bony pathology does not |
| Articular dysfunction (single segment) | Rotatores TrPs can induce concurrent single-level articular dysfunction; articular and myofascial components may coexist; treating one often helps the other; the spinous process tenderness is used as an osteopathic sign of articular dysfunction of that vertebra |
| Spinal stenosis | Deep paraspinal aching pain aggravated by extension; neurogenic claudication with standing and walking; distinguished by neurological examination and MRI; myofascial TrPs and stenosis may coexist |
Treatment
Trigger Point Release — Spray and Stretch
To stretch the rotatores, the seated patient's spine is simultaneously flexed and rotated, turning the chest toward the side of the involved muscle — the same technique as for the multifidi:
- After initial sweeps of spray, the operator takes up the slack that develops and repeats the process several times
- To incorporate PIR: the patient looks toward the contralateral side while the examiner resists any attempt to turn the torso, then relaxes and turns toward the involved side
- Release is augmented through reciprocal inhibition if the patient gently voluntarily assists rotation toward the involved side
- The spray pattern follows a diagonal direction corresponding to the diagonal fibre orientation
Trigger Point Injection
TrPs in the rotatores, which lie against the laminae of the vertebrae and attach at the base of each spinous process, require a needle at least 5 cm (2 in) long:
- The needle is directed somewhat caudally and medially, nearly parallel to the long axis of the spine
- The needle is aimed toward the base of the spinous process, not between the spinous processes
- This angle of approach eliminates the possibility of introducing the needle into the pleural cavity (between the ribs) or into the epidural space (between the vertebrae)
- Penetration to a depth greater than the laminae is unnecessary and undesirable
Manual Release
Many manual release techniques directed toward spinal articular dysfunctions are as effective for releasing the tense deep spinal muscles as they are for releasing restricted joint movement. Given the unique single-segment articular association of the rotatores, manual therapy directed at the identified dysfunctional segment is particularly relevant.
Satellite Trigger Points
- Multifidi — adjacent deeper paraspinal layer; commonly co-active
- Semispinalis thoracis — more superficial partner in the deep group
- Longissimus thoracis — overlying superficial layer at the same level
- Iliocostalis thoracis — superficial lateral layer
Related Pages
- Pain:Low Back — Diagnostic algorithm
- Pain:Mid Back Deep — Deep paraspinal "bone" pain at spinous process level
- Muscle:Multifidi — Adjacent partner; two-to-three segment articular involvement
- Muscle:Semispinalis Thoracis — More superficial deep partner; four-to-six segment involvement
- Muscle:Longissimus Thoracis — Overlying superficial layer
References
- Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 2: The Lower Extremities. Baltimore: Williams & Wilkins; 1992. Chapter 48.
- Macintosh JE, Bogduk N. The biomechanics of the lumbar multifidus. Clinical Biomechanics 1:205–213, 1986.