Corpus: Rotator muscles
1. Definition
The rotator muscles are skeletal muscles that are part of the deep back musculature and belong to the medial tract of the erector spinae muscle.
2. Course
The rotator muscles are most prominent in the thoracic spine but are inconsistently developed in the cervical and lumbar regions. There are three main types of rotator muscles, each corresponding to a region of the spine:
- Rotatores thoracis (thoracic spine)
- Rotatores lumborum (lumbar spine)
- Rotatores cervicis (cervical spine)
2.1. Rotatores thoracis
In the thoracic region, the rotator muscles run from the transverse process of one vertebra to the spinous process of the vertebra one or two levels above, situated beneath the multifidi muscles.
When the rotatores extend to the vertebra directly above, they are referred to as short rotators (rotatores breves). If they extend two vertebrae higher, they are called long rotators (rotatores longi).
2.2. Rotatores cervicis and lumborum
In the cervical spine, the rotator muscles run from the articular processes to the spinous processes of the vertebrae above. In the lumbar spine, they originate from the mammillary processes and attach to the spinous processes of the vertebrae above.
3. Innervation
The rotator muscles are innervated by the medial branches of the posterior rami from the respective segmental spinal nerves.
4. Function
When the rotator muscles contract unilaterally, they rotate the spinal column to the opposite side. Bilateral contraction results in the extension of the thoracic spine.