Thorax & Abdomen Quiz

Thorax & Abdomen

• Learning outcomes:
  • Describe the blood supply to the thorax and abdomen, including the walls and each of its components
  • Describe the venous drainage of the thorax and abdomen

Case Study: Abdominal Aortic Aneurysm

• A 72-year-old man with an abdominal aortic aneurysm (expansion of the infrarenal abdominal aorta) measuring 10cm
• Scheduled for repair

Arterial Supply to Thoracic Wall

• Posterior intercostal arteries:
  • 1st and 2nd intercostal spaces: supplied by supreme intercostal artery
  • 3rd-11th intercostal spaces: supplied by thoracic aorta
• Dorsal branch: supplies spinal cord and back muscles
• Collateral branch: supplies superior border of rib and anastomoses with anterior intercostals
• Anterior intercostal arteries:
  • Upper nine intercostal spaces: supplied by internal thoracic artery and musculophrenic artery
  • 10th-11th intercostal spaces: supplied by posterior intercostals and collateral branches

Vasculature of the Lungs

• Bronchial arteries:
  • Left bronchial artery: arises from thoracic aorta
  • Right bronchial artery: arises from aorta or posterior intercostal artery

Vasculature of the Heart

• Coronary arteries:
  • Right and left coronary arteries arise from corresponding aortic sinus and ascend aorta
  • Anastomosis vs. end arteries

Ascending Aorta

• Begins at aortic orifice
• Branches:
  • Left coronary artery
  • Right coronary artery
• Anastomosis vs. end arteries

Arch of Aorta

• Begins and ends at level T4/5
• Arches superior, posterior, and left; then inferiorly
• Left vagus nerve runs anterior to arch
• Branches:
  • Brachiocephalic trunk
  • Left common carotid artery
  • Left subclavian artery

Brachiocephalic Trunk

• First and largest branch of arch of aorta
• Posterior to manubrium and anterior to trachea on the right side
• Terminal branches:
  • Right subclavian artery
  • Right common carotid artery

Common Carotid Artery

• Left: arises from arch of aorta
• Right: arises from brachiocephalic trunk
• Supplies blood to head and neck
• Terminal branches:
  • External carotid artery
  • Internal carotid artery

Subclavian Artery

• Left: arises from arch of aorta
• Right: arises from brachiocephalic trunk
• Terminates at the lateral border of the 1st rib
• Continues as the axillary artery
• Divided into three parts by the anterior scalene muscle
• Branches:
  • Vertebral artery
  • Internal thoracic artery
  • Thyrocervical artery
  • Costocervical artery
  • Dorsal scapular artery

Descending Thoracic Aorta

• Continuation of the arch of aorta
• Begins at T4/5
• Lies on the left side of the posterior mediastinum
• Lies posterior to the root of the left lung
• Terminates as abdominal aorta as it passes through the diaphragm at T12
• Thoracic duct and azygos vein pass through aortic hiatus
• Branches:
  • Posterior intercostals (thoracic wall)
  • Bronchial arteries (lungs)
  • Oesophageal arteries (oesophagus)
  • Superior phrenic artery (diaphragm)

Blood Supply to Diaphragm

• Superior phrenic artery (diaphragm)
• Musculophrenic artery (diaphragm)
• Inferior phrenic artery (diaphragm)

Abdominal Aorta

• Begins at aortic hiatus
• Ends at level L4
• Branches of abdominal aorta distributed in three planes
• Terminal branches:
  • Common iliac arteries
• Branches:
  • Unpaired:
    • Celiac trunk
    • Superior mesenteric artery
    • Inferior mesenteric artery
  • Paired visceral:
    • Suprarenal artery
    • Renal artery
    • Gonadal artery
  • Paired parietal:
    • Subcostal artery
    • Inferior phrenic artery
    • Lumbar arteries

Celiac Trunk

• Supplies the foregut
• Branch of abdominal aorta at L1
• Branches:
  • Left gastric artery
  • Splenic artery
  • Common hepatic artery

Blood Supply to Stomach

• Right gastric artery
• Proper hepatic artery
• Left gastric artery
• Right gastro-omental artery
• Gastroduodenal artery
• Left gastro-omental artery
• Splenic artery
• Short gastric arteries
• Posterior gastric arteries