Internal thoracic artery:
It supplies the anterior wall of the body from the level of clavicle to umbilicus.
Origin: It originates as a branch of first part of subclavian artery in the neck.
Course: After its origin, it descends vertically over the pleura behind the costal cartilages and a fingerbreadth lateral to the sternum.
Termination: It ends in the sixth intercostal space by dividing into superior epigastric and musculophrenic arteries.
- Two anterior intercostal arteries: For each of the upper six intercostal spaces, it gives two branches known as the anterior intercostal arteries.
- Perforating arteries: These accompany the terminal branches of the intercostal nerves of the corresponding intercostal space.
- Pericardiophrenic artery: It accompanies the phrenic nerve and supplies the pericardium.
- Mediastinal arteries: They supply the contents of anterior mediastinum.
- Superior epigastric artery: It is one of the terminal branches of the internal thoracic artery. It enters the rectus sheath of the anterior abdominal wall and supplies the rectus muscle of abdomen as far as umbilicus.
- Musculophrenic artery: It is also one of the terminal branches of internal thoracic artery. It runs around the costal margin of diaphragm and supplies the lower intercostal spaces and diaphragm.
Internal thoracic vein:
Internal thoracic vein begins as a number of small veins that accompany the internal thoracic artery. These small veins eventually join each other to form one large vessel, the internal thoracic vein. It ends by draining into the brachiocephalic vein on each side.