Trunk (thorax, abdomen, back)

Semispinalis Thoracis

Musculus semispinalis thoracis

Origin

Transverse processes of T6-T10

Insertion

Spinous processes of C6-T4

Function

Extends the thoracic and lower cervical spine; contralateral rotation on unilateral contraction

Innervation

Dorsal rami of the thoracic spinal nerves

Movement & chain

Part of the transversospinalis system; works together with semispinalis cervicis and capitis in extension and rotation of the spine.

Palpation

Palpable in the medial groove of the upper thoracic spine adjacent to the T1–T6 spinous processes.

Clinical

Extends and rotates the upper thoracic spine; frequently hypertonic in postural hyperkyphosis and structural scoliosis.

Segmental innervation

Dorsal rami T6-T10

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)