Trunk (thorax, abdomen, back)

Interspinales Thoracis

Musculi interspinales thoracis

Origin

Spinous process of a thoracic vertebra (mainly T1-T2 and T11-T12)

Insertion

Spinous process of the adjacent thoracic vertebra above

Function

Segmental stabilization of the thoracic spine

Innervation

Dorsal rami of the thoracic spinal nerves

Movement & chain

Less consistently present in the thoracic region than cervically and lumbarly, because the long spinous processes and rib cage already provide substantial stability.

Palpation

Often rudimentary or absent in the mid-thoracic region; deep between adjacent thoracic spinous processes.

Clinical

Provide segmental thoracic stability; involved in localized interspinous ligament sprains and thoracic stiffness.

Segmental innervation

Dorsal rami T2-T12 (the small muscles are mainly present at levels T1-T2 and T11-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)