The musculophrenic artery is a blood vessel lying in the antero-lateral, lower part of thorax. It is one of the two terminal branches into which the internal thoracic artery divides, the other being the superior epigastric artery. The musculophrenic supplies the diaphragm and the lower intercostal muscles.
From its point of origin, the musculophrenic artery stretches obliquely downwards, running laterally, behind the cartilages of the false ribs. It travels laterally along the costal arch on the line of attachment of the costal part of the diaphragm to the thorax. It enters the diaphragm at the eighth or ninth costal cartilage, ending considerably in size opposite the last intercostal space.
The musculophrenic artery sends intercostal offshoots to the seventh, eighth, and ninth intercostal spaces. These branches become smaller in diameter as these spaces decrease in length. The musculophrenic also gives off collateral branches to supply the lower part of the pericardium and upper portions of abdominal muscles.
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| Above, the musculophrenic artery arising as one of the two terminal branches of the internal thoracic. |