Posterior Mediastinum: Azygous Vein & Thoracic Duct (MSØV)
1. Describe the origin, course, and tributaries of Azygous Vein:
- Origin: Right ascending lumbar vein and hemiazygos vein.
- Course: It ascends on the right side of the vertebral column, behind the root of the right lung, and crosses the midline at the level of T5 vertebra.
- Tributaries: It receives blood from the right intercostal veins, right subcostal vein, right ascending lumbar vein, and hemiazygos vein.
2. Mention the relations of Azygous Vein:
- Right pleura, right lung, right bronchus, right tracheobronchial lymph nodes, aortic arch, thoracic duct, and vertebral column.
3. Describe the origin, course, and tributaries of Thoracic Duct:
- Origin: Cisterna chyli.
- Course: It ascends on the right side of the aorta and crosses the midline at the level of T5 vertebra to reach the left side.
- Tributaries: It receives lymph from the lower limbs, abdomen, and left side of the thorax.
4. Mention the relations of Thoracic Duct:
- Aorta, vertebral column, left pleura, left lung, left bronchus, and left tracheobronchial lymph nodes.
5. Describe their applied anatomy:
- Azygous vein: It plays a significant role in the drainage of the right thoracic cavity.
- Thoracic duct: It is the main lymphatic vessel of the body and plays a crucial role in the immune system.
Developmental Process: Cisterna chyli → Thoracic duct → Lymphatic system
Applied Anatomy:
- Azygous vein is used as an anatomical landmark during thoracic surgeries.
- Thoracic duct is used as a landmark during thoracic surgeries, and its injury can lead to chylothorax.
Stepwise Anatomical Mechanism: step 1 → Lymph is collected from the body → step 2 → Cisterna chyli → step 3 → Thoracic duct → step 4 → Left jugulosubclavian junction.