Quick Facts
Origin: Transverse processes of thoracic vertebrae.
Insertion: Laminae and spinous processes of thoracic vertebrae two vertebral segments above.
Action: Extends and rotates trunk; stabilizes vertebral column.
Innervation: Medial branches of posterior rami of thoracic nerves.
Arterial Supply: Dorsal branches of posterior intercostal arteries.
Related parts of the anatomy
Origin
The long rotatores muscles originate from the posterior aspects of the transverse processes of thoracic vertebrae. There can be variations between individuals regarding the origin sites for the long rotatores muscles.
Insertion
The fibers of the long rotatores muscles travel superomedially to the thoracic vertebrae that are located two vertebral segments superior to their origin sites, and insert onto the:
- inferior aspects of their laminae;
- bases of their spinous processes.
For example, muscle fibers that originate from the seventh thoracic vertebra insert onto the fifth thoracic vertebra.
Key Features & Anatomical Relations
Overall, the rotatores muscles are the deepest of the three muscles of the transversospinal muscles. They are intrinsic muscles of the back and are present along the cervical, thoracic, and lumbar regions of the vertebral column. However, they are well developed, and therefore distinct, in the thoracic region only. They are composed of many individual muscles that are classified as belonging to either the:
- short rotatores muscles, which are composed of muscles that insert onto thoracic vertebrae that are one vertebral segment superior to their origin;
- long rotatores muscles, which are composed of muscles that insert onto thoracic vertebrae that are two vertebral segments superior to their origin.
Overall, the rotatores muscles are located:
- superficial to the thoracic vertebrae;
- deep to the multifidus muscles;
- medial to the external intercostal, levatores costarum breves and levatores costarum longi muscles;
- lateral to the interspinales muscles.
Actions
The long rotatores muscles are involved in multiple actions:
- during unilateral contraction, they rotate the trunk to the opposite side;
- during bilateral contraction, they extend the trunk;
- they help stabilize the vertebrae column (Netter, 2011).
References
Netter, F. H. (2011) Atlas of Human Anatomy. Netter Basic Science Series: Saunders/Elsevier.
