Rotatores

At a glance

English

Rotatores

Latin (TA2)

Rotatores

System

Muscle

Region

Neck

Side

Paired, left and right

About the rotatores

The rotatores are the deepest layer of the transversospinal muscles, lying directly on the vertebral arches under multifidus. They are found along the whole spine, in the neck, thorax and lower back, but are best developed in the thoracic region; in the neck they are small and irregular. They are named for their supposed rotating action, and are divided into cervical, thoracic and lumbar groups.

Each rotator is a small, roughly four-sided slip. It arises from the upper and back part of a transverse process and runs upwards and inwards to the lower edge and outer face of the next lamina up, some fibres reaching the base of the spine. These short rotatores join neighbouring vertebrae; long rotatores skip one level and end on the vertebra two above. In the neck they arise from the articular processes, since the cervical transverse processes are small. One or more may be missing at either end of a region.

Their size makes them weak movers. When one side acts, they help turn the vertebra above towards the opposite side, and acting together they assist extension. Much more important, they contain a very high density of muscle spindles, so they are thought to act chiefly as position sensors, reporting how each vertebra lies on the next and helping the nervous system control posture and spinal stability.

The rotatores are supplied by the medial branches of the dorsal rami of the spinal nerves at each level. Their blood comes from the dorsal branches of the segmental arteries: in the neck from the vertebral and deep cervical arteries, and in the thorax from the posterior intercostal arteries. They may contribute to deep, localised back or neck pain when strained, and are crossed in posterior approaches to the spine.

Attachments, action and supply

Origin

Upper and back part of the transverse process (articular processes in the neck).

Insertion

Lower border and outer face of a lamina one or two levels higher, reaching the base of the spine.

Action

Help rotate the vertebra above to the opposite side and assist extension; chiefly provide position sense.

Nerve supply

Medial branches of the dorsal rami of the spinal nerves.

Blood supply

Dorsal branches of segmental arteries (vertebral and deep cervical in the neck, posterior intercostal in the thorax).