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Upper and lower posterior dentate muscles
Last reviewed: 07.07.2025
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Two thin flat muscles are attached to the ribs - the upper and lower posterior serratus muscles.
The superior posterior serratus muscle (m. serratus posterior superior) is located under the rhomboid muscles, the muscle begins with a flat tendinous plate on the lower part of the nuchal ligament and the spinous processes of the VI-VII cervical and I-II thoracic vertebrae. Directed obliquely from top to bottom and laterally, the muscle is attached with separate teeth to the posterior surface of the II-V ribs, outward from their angles.
Function: Raises the ribs.
Innervation: intercostal nerves (ThI-ThIV).
Blood supply: posterior intercostal arteries, deep cervical artery.
The lower posterior serratus muscle (m. serratus posterior inferior) lies in front of the latissimus dorsi muscle, begins with a tendinous plate on the spinous processes of the XI-XII thoracic and I-II lumbar vertebrae. This muscle is fused with the superficial plate of the lumbosacral fascia and the beginning of the latissimus dorsi muscle, and is attached by separate muscle teeth to the four lower ribs.
Function: Lowers the ribs.
Innervation: intercostal nerves (ThIX-ThXII).
Blood supply: posterior intercostal arteries.
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