Subcostal Muscles

Description

Illustration of subcostal muscles

Subcostal muscles

Names

• Subcostal Muscles
• Musculi subcostales

General

• Thin muscles found on the posterior thoracic wall, bridging 2-3 intercostal spaces
• Contributes to the intrinsic musculature of the chest wall
• Assist with respiration by pulling the ribs inferiorly during respiration, support intercostal spaces, thorax

Gross Anatomy

• Originate from the inner surface of one rib near the posterior angle
• Fibers descend inferomedially
• Each muscle inserts on the inner surface of the 2nd or 3rd rib below its origin
• Most developed in the lower part of the thorax, sometimes fuse with innermost intercostals
• In the upper chest, considered rudimentary and sometimes do not exist

Anatomic Relationships

• Found laterally to the thoracic vertebrae
• In contact with the innermost intercostals, may sometimes fuse
• Posterior surface lies over the inner surface of ribs, internal intercostals
• Anterior surface in relation with endothoracic fascia, parietal pleura

Innervation

• Intercostal Nerves

Vascular Supply

• Muscular branches of the posterior intercostal and musculophrenic arteries
• Drained by intercostal veins, empty into azygos and brachiocephalic veins

Function

• Belong to the accessory respiratory musculature
• Depress ribs during forced exhalation

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Clinical Significance

• Needs to be updated

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See Also

• Physical Exam Torso
• Torso Anatomy (Main)
• Chest Pain (Main)

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