Rotatores Breves (Thoracis)
Back · Trunk
The rotatores breves are the shorter of the two rotatores sets and lie in the very deepest layer of the transversospinales, most clearly developed in the thoracic region. Each arises from the transverse process of a thoracic vertebra and runs upward and medially to attach to the lamina and base of the spinous process of the immediately adjacent vertebra above. Spanning only a single segment, they rotate the thoracic spine toward the opposite side and, above all, stabilise adjacent vertebrae while supplying rich proprioceptive information about the spine. They are innervated by the posterior (dorsal) rami of the thoracic spinal nerves. Their extremely short fibres make them monitors of position more than generators of movement.
Origin, Insertion, Action & Nerve
Origin
Transverse process of a thoracic vertebra
Insertion
Lamina and base of the spinous process of the adjacent vertebra above
Action
Rotates the thoracic spine to the opposite side and stabilizes adjacent vertebrae
Nerve
Posterior (dorsal) rami of thoracic spinal nerves
Attachments explained
The Rotatores Breves (Thoracis) is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Transverse process of a thoracic vertebra
Insertion
Lamina and base of the spinous process of the adjacent vertebra above
Action & function
When the Rotatores Breves (Thoracis) contracts, it produces the following movement: Rotates the thoracic spine to the opposite side and stabilizes adjacent vertebrae.
As part of the Back group of the Trunk, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Rotatores Breves (Thoracis) receives its nerve supply from the Posterior (dorsal) rami of thoracic spinal nerves.
Because a muscle can only contract when its nerve is intact, injury to the Posterior can weaken or paralyse the Rotatores Breves (Thoracis), impairing the movements it normally produces (rotates the thoracic spine to the opposite side and stabilizes adjacent vertebrae). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Rotatores Breves (Thoracis) (the OIANS method)
Fix rotatores breves as the single-segment version of the rotatores: transverse process to the spinous process of the very next vertebra above. Being the shortest muscles in the deepest layer, they can produce only weak opposite-side rotation, so treat their true job as steadying one joint at a time and feeding the nervous system detailed position data.
Contrast breves directly with longi to lock in both: breves span one segment, longi span two, and both are essentially thoracic. Because their fibres are so short and packed with muscle spindles, think of the rotatores breves as proprioceptive sensors of the spine, which is a more accurate mental model than picturing them as rotators.
Frequently asked questions
Where is the Rotatores Breves (Thoracis) located?
The Rotatores Breves (Thoracis) is a muscle of the Back group, located in the Trunk.
What is the origin of the Rotatores Breves (Thoracis)?
Transverse process of a thoracic vertebra
What is the insertion of the Rotatores Breves (Thoracis)?
Lamina and base of the spinous process of the adjacent vertebra above
What movements does the Rotatores Breves (Thoracis) produce?
Rotates the thoracic spine to the opposite side and stabilizes adjacent vertebrae
What nerve supplies the Rotatores Breves (Thoracis)?
Posterior (dorsal) rami of thoracic spinal nerves
Is the Rotatores Breves (Thoracis) free to study in OIANS?
The Rotatores Breves (Thoracis) is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Trunk is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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