Multifidus

Origin, Insertion, Action, Innervation

Origin: Sacrum (posterior surface), PSIS, mammillary processes of the lumbar vertebrae, transverse processes of the thoracic vertebrae, and articular processes of C4–C7
Insertion: Spinous processes of vertebrae 2–4 levels above the origin (each fascicle spans 2–4 segments)
Action:
Primary: Segmental stabilization of the vertebral column — controls intervertebral motion segment by segment
Extension of the vertebral column (bilateral — but this is secondary to its stabilization role)
Contralateral rotation (minor — each fascicle rotates the superior vertebra away from the side of contraction)
Innervation: Dorsal rami of the spinal nerves (segmental — each fascicle innervated by the medial branch of the dorsal ramus at its level)

Palpation Guide

Client position: Prone with a pillow under the abdomen to reduce lumbar lordosis.
Landmark sequence:

Multifidus lies in the paravertebral gutter immediately adjacent to the spinous processes, deep to the erector spinae. It is the deepest muscle you can palpate in the posterior trunk.
In the lumbar region, multifidus is thickest — press firmly into the gutter between the spinous processes and the erector mass, approximately 1–2 cm from the midline. You are pressing through the erector spinae to reach multifidus.
The lumbar multifidus fills the "gutter" between the L4–S1 spinous processes and the erector mass — it is a substantial, thick muscle at this level.
In the thoracic and cervical regions, multifidus is thinner and harder to distinguish from spinalis and the rotatores.

Tissue feel: In the lumbar region, a well-developed multifidus feels firm, thick, and "meaty" when palpated deep in the paravertebral gutter. In atrophied states (chronic low back pain), the gutter feels flat, thin, and "empty" compared to the normal side — this asymmetric wasting is palpable and visible on imaging.
Confirmation test: Ask the client to gently extend the spine (lift the chin slightly). The multifidus should firm up under your fingers deep in the paravertebral gutter. In clients with multifidus inhibition, you may feel the erector spinae contract prominently while the deep gutter remains soft — indicating the global muscles are compensating for the inhibited local stabilizer.
Common errors:
Palpating the erector spinae (longissimus/iliocostalis) and calling it multifidus — you must press past the erector mass to reach multifidus in the deep gutter. If you are on a large, superficial muscle mass, you are on the erectors.
Assuming bilateral symmetry — multifidus frequently atrophies unilaterally (on the painful side) in low back pain. Always compare left to right.

Trigger Point Referral

Common TrP locations: TrPs are found at each segmental level, particularly L4–S1 where multifidus is thickest. TrPs are localized deep in the paravertebral gutter, close to the spinous processes.
Referral pattern: Refers locally to the adjacent spinal level and may refer into the buttock. The referral is deep, poorly localized, and aching — clients have difficulty pointing to a specific spot.
Clinical significance: The deep, poorly localized quality of multifidus TrP referral mimics facet joint pain or disc-related pain. If a client has deep lumbar pain that does not follow a dermatomal pattern and is not reproduced by facet loading tests (extension + rotation), consider multifidus TrPs.

Trigger point referral diagram — coming soon

Image coming soon. For visual reference, see [Multifidus at TriggerPoints.net](http://www.triggerpoints.net/muscle/multifidus).

Clinical Notes

Stabilization significance:

Multifidus and transversus abdominis form the deep local stabilization system of the lumbar spine. Multifidus provides posterior segmental control while TrA provides anterior circumferential compression. Both are inhibited in chronic low back pain (Hides et al., 1996), and both require specific motor control retraining — not just general strengthening.
Multifidus atrophy occurs rapidly after a first episode of acute low back pain (within days) and does not recover spontaneously even when pain resolves. This persistent atrophy predicts recurrence — clients who do not retrain multifidus have significantly higher recurrence rates.

Common conditions:

The most consistently documented finding in chronic conditions/low-back-pain is multifidus wasting at the symptomatic level. This is visible on ultrasound and MRI, and palpable as a "flat" or "empty" paravertebral gutter on the affected side.
Part of the deep stabilization system disrupted in conditions/lower-crossed-syndrome — while the erector spinae (global muscles) tighten, multifidus (local stabilizer) becomes inhibited. This is a fundamental distinction: the back feels "tight" because the erectors are overworking to compensate for the inhibited multifidus.
Involved in conditions/facet-joint-syndrome — multifidus controls segmental motion at the facet joints. When inhibited, the segment becomes hypermobile, and the facet joints are loaded abnormally.

What you'll typically find:

In clients with acute low back pain, the multifidus on the affected side is often inhibited and may already be atrophying. Palpation reveals a "flat" gutter compared to the contralateral side, while the overlying erectors are hypertonic (compensating).
In chronic low back pain, the asymmetric wasting pattern is established — one side is noticeably smaller and softer than the other. This finding guides the rehabilitation prescription.

Treatment effects:

Direct manual treatment of multifidus (deep sustained compression in the paravertebral gutter) can reduce local TrP pain and improve segmental mobility.
However, the primary intervention for multifidus dysfunction is motor control retraining — isometric activation of multifidus at the segmental level while maintaining a neutral spine. Massage therapy's role is to facilitate this retraining by reducing pain, releasing compensatory erector hypertonicity, and improving the client's ability to recruit the deep system.
Releasing the hypertonic erectors first allows the client to access the deep multifidus more effectively during retraining exercises.

Cautions:

Deep pressure in the paravertebral gutter should be applied carefully — you are pressing close to the spinous processes and the underlying facet joints. If the client reports sharp, localized pain that worsens with your pressure, you may be loading a sensitized facet joint rather than treating muscle.
In acute disc herniation, avoid deep paravertebral pressure at the affected level — the segment is already unstable and deep compression can increase symptoms.

Clinical pearl:

When a client's low back feels "tight" but the erectors are already released and the tightness persists, the problem is not residual erector tension — it is multifidus inhibition. The brain perceives the unstabilized segment as "tight" (a protective perception) even though the muscle is actually weak and atrophied. The solution is not more release — it is retraining the multifidus. Knowing this distinction prevents the common trap of chasing "tightness" that is actually instability.

Assessment

Manual muscle testing:

Segmental multifidus activation: Client prone. Palpate the paravertebral gutter at the target level. Ask the client to gently "swell" the muscle under your finger (subtle isometric extension at one level) without lifting the trunk. Compare bilateral response — the inhibited side fails to activate or activates with a delay.

Stretch test:

Multifidus does not have a standard clinical stretch test. Assessment focuses on activation ability and size symmetry rather than length.

Related special orthopedic tests:

Prone instability test — pain with posteroanterior pressure that resolves when the client lifts the feet off the floor (activating trunk muscles) suggests segmental instability that multifidus retraining would address
Real-time ultrasound — can visualize multifidus thickness and activation at each level

Muscle Groups

Local spinal stabilizers (functional — deep system):

Multifidus (this article)
anatomy/muscles/transversus-abdominis
anatomy/muscles/diaphragm
Pelvic floor muscles

Transversospinalis group (anatomical — deep posterior):

Multifidus (this article)
anatomy/muscles/rotatores
Semispinalis

Medial paravertebral muscles (anatomical):

Related Muscles

Functional partner (deep stabilization cylinder):

anatomy/muscles/transversus-abdominis — anterior local stabilizer; co-activates with multifidus

Synergists for trunk extension (global):

anatomy/muscles/erector-spinae-iliocostalis — global extensor (compensates when multifidus is inhibited)
anatomy/muscles/erector-spinae-longissimus — global extensor

Same anatomical group (transversospinalis):

anatomy/muscles/rotatores — deepest layer; spans 1–2 segments

Key Takeaways

Multifidus atrophies rapidly after acute low back pain and does not recover spontaneously — specific motor control retraining is required, not just general strengthening.
The "tight" back in low back pain is often multifidus inhibition, not erector hypertonicity — the brain perceives instability as tightness. More release is not the answer; retraining is.
Multifidus and TrA form the deep stabilization system — dysfunction in either predicts low back pain recurrence and guides the rehabilitation prescription.