Cisterna chyli

The cisterna chyli (CC), also known as the receptaculum chyli,is a normal anatomical structure in the lymphatic system. It is seen as a saccular area of dilatation in the lymphatic channels that are located in the retrocrural space, usually to the immediate right of the abdominal aorta.

Gross anatomy

Location

The cisterna chyli is located at the level of L1 and L2 vertebral bodies immediately right to the aorta behind the right crus of the diaphragm.

Origin

It is an elongated, sac-like structure formed by the junction of a variable number of lumbar, intestinal, liver and descending intercostal lymphatic trunks. It extends 5-7 cm in the caudocephalad axis.

Termination

The upper end of the cisterna chyli continues as the thoracic duct to empty into the left subclavian vein.

Drainage

Receives lymph from the abdominal wall, non-alimentary viscera and lower extremities.

Relations

• anteriorly: right crus of the diaphragm
• posteriorly: L1 and L2 vertebral bodies
• left laterally: abdominal aorta
• right laterally: azygos vein

Radiographic features

CT

The cisterna chyli can be identified as a rounded-to-elliptical retrocrural structure with an average attenuation of 4 HU. There is no enhancement following intravenous contrast administration.

MRI

The signal intensity characteristics of the cisterna chyli on MRI are the same as those for static or slow-moving fluids with high signal intensity on fluid-sensitive MR sequences ³.

Differential diagnosis

On CT consider:

• enlarged retrocrural lymph node ¹
• small neurenteric cyst