Levatores Costarum Longi 1–4
Thorax · Trunk
The levatores costarum longi are the longer of the two sets of rib-elevating muscles found on the posterior thoracic wall. Each arises from the transverse process of a vertebra between C7 and T11 and passes downward and laterally, but rather than reaching the immediately adjacent rib it skips one to insert onto the outer surface of the rib two levels below, between its tubercle and angle. This oblique, longer course allows them to elevate the ribs to aid inspiration and to assist lateral flexion of the vertebral column. They are supplied 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 two levels 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 Longi 1–4 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 two levels below, between the tubercle and angle
Action & function
When the Levatores Costarum Longi 1–4 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 Longi 1–4 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 Longi 1–4, 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 Longi 1–4 (the OIANS method)
Separate the long and short levatores costarum by counting ribs. The long variety, studied here, bypasses the nearest rib and lands on the rib two levels below, which distinguishes it from the short set that attaches to the very next rib. The name levatores costarum literally means lifters of the ribs, so its inspiratory action is built into the title.
Note the unusual innervation for a thoracic wall muscle: although it moves ribs, it is supplied by posterior (dorsal) rami, aligning it with the deep back muscles rather than the intercostal nerves. Pairing that dorsal ramus rule with the two-rib span gives you both the distinguishing action and the nerve in one step.
Frequently asked questions
Where is the Levatores Costarum Longi 1–4 located?
The Levatores Costarum Longi 1–4 is a muscle of the Thorax group, located in the Trunk.
What is the origin of the Levatores Costarum Longi 1–4?
Transverse processes of C7–T11
What is the insertion of the Levatores Costarum Longi 1–4?
Outer surface of the rib two levels below, between the tubercle and angle
What movements does the Levatores Costarum Longi 1–4 produce?
Elevates the ribs (aiding inspiration) and assists lateral flexion of the vertebral column
What nerve supplies the Levatores Costarum Longi 1–4?
Posterior (dorsal) rami of C8–T11 spinal nerves
Is the Levatores Costarum Longi 1–4 free to study in OIANS?
The Levatores Costarum Longi 1–4 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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