Levatores Costarum Breves 1–12
Thorax · Trunk
The levatores costarum breves are the shorter set of rib-elevating muscles on the posterior thoracic wall. Each arises from the transverse process of a vertebra between C7 and T11 and runs downward and laterally to insert onto the outer surface of the rib immediately below, between its tubercle and angle. By pulling on these ribs they elevate them to aid inspiration and assist lateral flexion of the vertebral column. Like their longer counterparts, they are innervated by the posterior (dorsal) rami of the C8 to T11 spinal nerves.
Origin, Insertion, Action & Nerve
Origin
Transverse processes of C7–T11
Insertion
Outer surface of the rib immediately below, between the tubercle and angle
Action
Elevates the ribs (aiding inspiration) and assists lateral flexion of the vertebral column
Nerve
Posterior (dorsal) rami of C8–T11 spinal nerves
Attachments explained
The Levatores Costarum Breves 1–12 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 processes of C7–T11
Insertion
Outer surface of the rib immediately below, between the tubercle and angle
Action & function
When the Levatores Costarum Breves 1–12 contracts, it produces the following movement: Elevates the ribs (aiding inspiration) and assists lateral flexion of the vertebral column.
As part of the Thorax 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 Levatores Costarum Breves 1–12 receives its nerve supply from the Posterior (dorsal) rami of C8–T11 spinal nerves. This nerve carries fibres from spinal segment(s) C8, T11.
Because a muscle can only contract when its nerve is intact, injury to the Posterior or to its spinal roots (C8, T11) can weaken or paralyse the Levatores Costarum Breves 1–12, impairing the movements it normally produces (elevates the ribs (aiding inspiration) and assists lateral flexion of the vertebral column). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Levatores Costarum Breves 1–12 (the OIANS method)
Learn the short levatores costarum in direct contrast with the long set: the short slips reach only the next rib down, one segment away, while the long slips reach the rib two levels below. Both attach between the tubercle and angle of the rib, so the span is the single feature that tells them apart.
Reinforce that, despite acting on ribs, these muscles belong to the deep back by innervation and take posterior (dorsal) rami of C8 to T11. Grouping breves and longi together as a pair, identical in origin, action, and nerve but differing only in reach, is the most efficient way to master both.
Frequently asked questions
Where is the Levatores Costarum Breves 1–12 located?
The Levatores Costarum Breves 1–12 is a muscle of the Thorax group, located in the Trunk.
What is the origin of the Levatores Costarum Breves 1–12?
Transverse processes of C7–T11
What is the insertion of the Levatores Costarum Breves 1–12?
Outer surface of the rib immediately below, between the tubercle and angle
What movements does the Levatores Costarum Breves 1–12 produce?
Elevates the ribs (aiding inspiration) and assists lateral flexion of the vertebral column
What nerve supplies the Levatores Costarum Breves 1–12?
Posterior (dorsal) rami of C8–T11 spinal nerves
Is the Levatores Costarum Breves 1–12 free to study in OIANS?
The Levatores Costarum Breves 1–12 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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