Ventral parts of lateral intertransversarii lumborum muscles

At a glance

English

Ventral parts of lateral intertransversarii lumborum muscles

Latin (TA2)

Partes ventrales musculorum intertransversariorum lateralium lumborum

System

Muscle

Region

Back

Side

Paired, left and right

About the ventral parts of lateral intertransversarii lumborum muscles

The intertransversarii are short muscles that fill the spaces between the transverse processes of neighbouring vertebrae. In the lumbar region each side has a medial set and a lateral set, and each lateral muscle can be divided into a ventral part in front and a dorsal part behind. The ventral parts are the front slips of the lateral set.

Each ventral part passes from the lower border of one lumbar transverse process to the upper border of the next transverse process down. The slips are thin and short and lie close to the front of the lumbar spine, behind psoas major and medial to quadratus lumborum. The lumbar ventral rami emerge in front of them as they leave the intervertebral foramina.

Because they lie at the side of the vertebral column, they can bend the lumbar spine towards their own side and help to steady each segment. Their force is small compared with that of quadratus lumborum and psoas. Like other tiny spinal muscles they are thought to work largely as sensors of the position of each vertebra.

They are supplied by ventral rami of the lumbar spinal nerves, which, together with their position, links them by development to the muscles of the body wall rather than to the true back muscles. Their blood comes from branches of the lumbar arteries.

Attachments, action and supply

Origin

Lower border of a lumbar transverse process.

Insertion

Upper border of the transverse process of the next lumbar vertebra down.

Action

Helps to bend the lumbar spine to the same side and steady each segment; supplies position sense.

Nerve supply

Ventral rami of the lumbar spinal nerves.

Blood supply

Branches of the lumbar arteries.