Trunk (thorax, abdomen, back)

Multifidus, thoracic part

Musculus multifidus (pars thoracis)

Origin

Transverse processes of the thoracic vertebrae

Insertion

Spinous processes 2 to 4 vertebrae above

Function

Segmental stabilization and slight extension/rotation of the thoracic spine

Innervation

Dorsal rami of the thoracic spinal nerves

Movement & chain

Like the other multifidus segments, contributes to segmental stabilization through continuous low-grade feedforward activity, with a smaller range of motion than the lumbar portion due to the restraining action of the rib cage.

Palpation

Palpable in the deep groove between thoracic spinous and transverse processes beneath the semispinalis layer.

Clinical

Segmental stabilizer resisting shear and torsion in the thoracic spine; dysfunction correlates with localized thoracic facet pain.

Segmental innervation

Dorsal rami T1-T12

In clinical practice

Ergonomic patient repositioning (log-roll technique in spinal trauma) and pressure offloading; maintain neutral spinal alignment in bedridden patients.

Region in the model

Trunk (thorax, abdomen, back)