Trunk (thorax, abdomen, back)

Interspinales Lumborum

Musculi interspinales lumborum

Origin

Spinous process of a lumbar vertebra (L1-L4)

Insertion

Spinous process of the lumbar vertebra below (L2-L5)

Function

Extension and segmental stabilization of the lumbar spine

Innervation

Dorsal rami of the lumbar spinal nerves

Movement & chain

Like the cervical variant, mainly important proprioceptively for segmental control between adjacent vertebrae.

Palpation

Deep between adjacent lumbar spinous processes L1–L5; palpable as deep midline interspinous resistance.

Clinical

Reinforce lumbar lordosis and prevent shear forces during forward flexion; strained in acute mechanical low back pain (lumbago).

Segmental innervation

Dorsal rami L2-L5.

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)