The thoracic duct is the largest lymphatic vessel that extends from the upper abdomen to the lower neck. It begins near the 12th thoracic vertebrae and ascends through the posterior mediastinum before passing into the superior mediastinum. In the neck, it opens at the junction of the left subclavian and left internal jugular veins. It receives lymph from the lower body and left side of the body above the diaphragm. Obstruction or injury to the thoracic duct can lead to conditions such as chylothorax.

1. THORACIC DUCT

2. LEARNING OBJECTIVE
• Introduction
• Course
• Relations
• Tributaries
• Clinical

3. INTRODUCTION
 The Thoracic Duct is the largest lymphatics vessel of the body.
Extend from upper part of abdomen to lower part of neck.
Cross posterior and superior parts of mediastinum.

4. 1. The thoracic duct begins as a continuation of the upper end
of the cisterna chyli near the lower border of the
12th thoracic vertebra
2. Enters the thorax through the aortic opening of the diaphragm.
COURSES

5. 3. then ascends through the posterior mediastinum from level
of 12th thoracic vertebra to fifth thoracic vertebra.
4. Then it courses through the superior mediastinum.
 DIG- POSTERIOR MEDIASTINUM

6. 5. In the neck, it arches laterally at the
level of 7th cervical vertebra.
6. And open at the junction of
left subclavian and left internal jugular vein.
 LEFT INTERNAL
JUGULAR VEIN
 Left subclavian vein

7. Relations
At aortic opening of diaphragm
Ant – Diaphragm
Post – vertebral colum
To the right – Azygos vein
To the left - AORTA
In the posterior mediastinum
Ant – (1) Diapragm
(2) Oesophagus
Post - (1) Vertebral column
(2) Rt Posterior intercostal arteries
To the right - AZYGOS VEIN
To the left – Descending Aorta
 DIGRAM- POSTERIOR
MEDIASTINUM

8. In the superior Mediastinum
Ant- Arch of aorta
Post- vertebral column
To the right- Oesophagus
To the left- Pleura
In the neck
The thoracic duct forms an arch rising about 3-4cm above the clavicle.
Ant- Lt common carotid artery
Lt vagus
Internal jugular vein
Post – Vertebral artery
sympathetic trunk
Lt Pherenic nerve

9. Tributaries
1.) Thoracic duct recive lymph from both half of the body below the
diaphragm and left half above the abdomen.
2) In thorax thoracic duct receive – lymph vessel from posterior
mediastinal node and small intercostal node.
3) Left jugular trunk, Left subclavian trunk end in thoracic duct.
4) Left bronchiomediastinal trunk – drain lymph from Left half of thorax
And ends in thoracic duct
Rt half above diaphragm
Rt side there is lymphatic duct Into which 
(1) Rt brachiomediastinal
(2) Rt jugular
(3) Rt subclavianlymph drain
Rt lymphatic trunk end in Rt brachiocephalic vein

10. Applied anatomy
 Thoracic duct is very thin walled and colourless so more prone for injury
during surgery in post mediastinum.
Obstruction of Thoracic duct - Due to mature filarial parasites lymph
vessels get burst chylothorax, chyloperitoneum, chyluria.
 Cervical part of thoracic duct is damaged in block dissection of neck