Anatomy study note · Thorax

Levatores costarum

Twelve pairs of small triangular muscles at the back of the thorax, each running from a transverse process to the rib below.

Key points

• 12 pairs: transverse process (C7–T11) → rib below.
• Posterior rami of thoracic nerves.
• Elevate ribs; probably proprioceptive.
• Trunk muscles: from myotomes of the somites.
• Dorsal part → dorsal-ramus muscles; ventral part → ventral-ramus muscles.
• Skeletal muscle: multinucleated, peripheral nuclei, striated.
• Epimysium → perimysium → endomysium.

The full note in the atlas also covers

Origin · Insertion · Action · Nerve supply · Histology · Development

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Written from

• Snell’s Clinical Anatomy by Regions, 10th ed., ch. 4, PDF pp. 494, 503
• Inderbir Singh’s Human Embryology, ch. 7, PDF pp. 108–109
• BRS Cell Biology & Histology, 7th ed., ch. 8, PDF pp. 135–144

More from the thorax

• Lung
• Lymph nodes of the thoracic wall
• Main and lobar bronchi
• Mediastinal and tracheobronchial lymph nodes
• Mitral valve
• Pulmonary trunk
• Pulmonary valve
• Pulmonary veins
• Ribs
• Right atrium
• Right coronary artery
• Right ventricle

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