[level-membership-for-cardiothoracic-surgery-category]Chapter 5

Cisterna Chyli/Thoracic Duct Axial 1

Normal Anatomy

A normal structure is shown—the cisterna chyli—which is inconsistently seen on clinical thoracic CT scans. The cisterna chyli is typically located between the distal thoracic or upper abdominal aorta and azygos vein in the right posterior mediastinum or retrocrural space, posterior to the right diaphragmatic crus. The cisterna chyli receives lymph from the right and left lumbar lymphatic trunks, the intestinal lymphatic trunk, and the inferior intercostal lymph nodes. The cisterna chyli gives rise to the thoracic duct, whose course will be shown on subsequent images.

Cisterna Chyli/Thoracic Duct Axial 2

Normal Anatomy

The thoracic duct is not always visible on thoracic CT scans, but is well seen in this patient. The thoracic duct originates from the cisterna chyli and ascends within the posterior mediastinum. The thoracic duct is well visualized adjacent to the azygos vein, posterior to the esophagus. Caudally, it usually ascends on the right side, often crossing to the left of midline at approximately the level of the 5th thoracic vertebral body. In this patient, the thoracic duct crossed midline at a more inferior level than is typically seen.

Cisterna Chyli/Thoracic Duct Axial 3

Normal Anatomy

The thoracic duct is again seen coursing within the posterior mediastinum adjacent to the azygos vein and descending thoracic aorta and posterior to the esophagus.

Cisterna Chyli/Thoracic Duct Axial 4

Normal Anatomy

At the level of the aortic arch at the cranial aspect of the azygos vein, the thoracic duct is again seen to the left of midline, posterior to the esophagus.

Cisterna Chyli/Thoracic Duct Axial 5

Normal Anatomy

Within the superior mediastinum, the thoracic duct is visible to the left of midline. The thoracic duct courses cranially and eventually empties into the junction of the left subclavian and left internal jugular veins. The thoracic duct drains lymph from the entire body except for the right head and neck, right thorax, and right arm.

Cisterna Chyli/Thoracic Duct Coronal 1

Normal Anatomy

This coronal image, and those that follow, accompanies Cisterna Chyli/Thoracic Duct Axial 1-5 above and shows the position of the cisterna chyli and course of the thoracic duct in the coronal plane. The thoracic duct is not always visible on thoracic CT scans, but is well seen in this patient. The thoracic duct originates from the cisterna chyli and ascends within the posterior mediastinum. In this image, the thoracic duct is well visualized to the left of midline, in proximity to the azygos vein. The thoracic duct usually ascends on the right side, often crossing to the left of midline at approximately the level of the 5th thoracic vertebral body.

Cisterna Chyli/Thoracic Duct Coronal 2

Normal Anatomy

The thoracic duct is again seen coursing within the posterior mediastinum to the left of midline superiorly, in close proximity to the esophagus. Inferiorly, the thoracic duct is again visible medial to the azygos vein as it is crossing midline from right to left.

Cisterna Chyli/Thoracic Duct Coronal 3

Normal Anatomy

Slightly anterior to the two preceding views, the thoracic duct is shown on both sides of midline, to the right inferiorly and to the left superiorly.

Cisterna Chyli/Thoracic Duct Coronal 4

Normal Anatomy

Still slightly more anteriorly located than preceding views, portions of the central pulmonary arteries and veins are shown. At this level, the thoracic duct is seen inferiorly, to the right of midline, adjacent to the descending thoracic aorta.

Cisterna Chyli/Thoracic Duct Coronal 5

Normal Anatomy

The left superior pulmonary vein is shown as it enters the left atrium. The cisterna chyli is now visible posteriorly on the right at the thoracoabdominal junction. The cranial portion of the thoracic duct is visible to the left of midline, adjacent to the esophagus and thoracic aorta.

Cisterna Chyli/Thoracic Duct Coronal 6

Normal Anatomy

The cranial portion of the thoracic duct is shown in close proximity to the esophagus. The right superior intercostal vein, which drains the 2nd, 3rd, and 4th posterior intercostal veins, can be seen draining into the azygos vein.

Cisterna Chyli/Thoracic Duct Coronal 7

Normal Anatomy

Again, the cranial portion of the thoracic duct is shown in close proximity to the esophagus, beginning to extend cranial to the thoracic aortic arch. The right superior intercostal vein is again seen draining into the azygos vein.

Cisterna Chyli/Thoracic Duct Coronal 8

Normal Anatomy

This view, anteriorly located relative to preceding views, shows the cranial portion of the thoracic duct adjacent to the esophagus, cranial to the thoracic aortic arch.

Cisterna Chyli/Thoracic Duct Coronal 9

Normal Anatomy

The most anteriorly positioned of the preceding views, detailing the course of the thoracic duct, shows the thoracic duct extending cranially toward the root of the neck, prior to entry into the junction of the left subclavian and internal jugular veins.

[/level-membership-for-cardiothoracic-surgery-category][not-level-membership-for-cardiothoracic-surgery-category]Chapter 5

Cisterna Chyli/Thoracic Duct Axial 1

Normal Anatomy

A normal structure is shown—the cisterna chyli—which is inconsistently seen on clinical thoracic CT scans. The cisterna chyli is typically located between the distal thoracic or upper abdominal aorta and azygos vein in the right posterior mediastinum or retrocrural space, posterior to the right diaphragmatic crus. The cisterna chyli receives lymph from the right and left lumbar lymphatic trunks, the intestinal lymphatic trunk, and the inferior intercostal lymph nodes. The cisterna chyli gives rise to the thoracic duct, whose course will be shown on subsequent images.

Cisterna Chyli/Thoracic Duct Axial 2

Normal Anatomy

The thoracic duct is not always visible on thoracic CT scans, but is well seen in this patient. The thoracic duct originates from the cisterna chyli and ascends within the posterior mediastinum. The thoracic duct is well visualized adjacent to the azygos vein, posterior to the esophagus. Caudally, it usually ascends on the right side, often crossing to the left of midline at approximately the level of the 5th thoracic vertebral body. In this patient, the thoracic duct crossed midline at a more inferior level than is typically seen.

Cisterna Chyli/Thoracic Duct Axial 3

Normal Anatomy

The thoracic duct is again seen coursing within the posterior mediastinum adjacent to the azygos vein and descending thoracic aorta and posterior to the esophagus.

Cisterna Chyli/Thoracic Duct Axial 4

Normal Anatomy

At the level of the aortic arch at the cranial aspect of the azygos vein, the thoracic duct is again seen to the left of midline, posterior to the esophagus.

[/not-level-membership-for-cardiothoracic-surgery-category]

Netters Correlative Imaging Cardiothoracic Anatomy