and Edgar D. Guzman-Arrieta3
(1)
Department of Surgery Advocate Illinois Masonic Medical Center, University of Illinois Metropolitan Group Hospitals Residency in General Surgery, Chicago, IL, USA
(2)
University of Illinois at Chicago, Chicago, IL, USA
(3)
Vascular Specialists – Hattiesburg Clinic, Hattiesburg, MS, USA
Keywords
Lymphatic channelsLymph nodesThoracic ductCystic hygromasChylothorax1.
All of the following are correct except:
(a)
The lymphatic system is derived from the mesoderm.
(b)
The lymphatic system originates from the venous system.
(c)
The remnant of the right thoracic duct drains the upper right hemithorax.
(d)
Congenital lymphedema (lymphedema praecox) is caused by hyperplasia of the lymphatic vessels.
(e)
Visceral lymphatics have no valves.
Comments
Please see question 3.
Answer
d
2.
All of the following are correct except:
(a)
Lymphatic capillaries lack a continuous basal membrane.
(b)
Extremity lymphatic vessels have valves.
(c)
The thoracic duct is interrupted by lymph nodes.
(d)
The lymph is propelled by transient increases in tissue pressure.
(e)
Reflux of blood from the jugular vein into the thoracic duct is prevented by valves.
Comments
Please see question 3.
Answer
c
3.
All of the following are correct except:
(a)
The cisterna chyli represents the confluence of the bilateral lumbar and intercostal trunks with the unpaired intestinal trunk.
(b)
The cisterna chyli gives origin to the thoracic duct and lies to the right of T12.
(c)
The thoracic duct receives multiple intercostal branches in its ascent through the thorax.
(d)
The thoracic duct traverses the diaphragm through the caval hiatus.
(e)
The rate of flow along the thoracic duct fluctuates between 60 and 190 ml/h.
Comments
The lymphatic system, like the remainder of the vascular system, is thought to arise from the mesoderm. The lymphatic system arises from six primordial lymph sacs that are outgrowths of venous channels, paralleling the six aortic arches from the branchial apparatus. The first primordial lymph sacs arise at the jugular–subclavian confluences and extend into the upper extremities and head. Two unpaired sacs appear along the mesenteric and celiac trunks and form the cisterna chyli. Finally, paired femoral sacs appear and extend into the lower extremities. These six sacs become linked by a rich network of lymphatic vessels, ultimately leading from the peripheral tissues to the central veins. Lymph nodes develop at a later stage at places where lymphatic channels join.
The right and left thoracic ducts are derived from the jugular–subclavian lymph sacs. Originally, they both connect to the cisterna chyli and drain lymph towards the subclavian vessels. Later in development the distal portion of the right thoracic duct crosses over the midline behind the esophagus to join the proximal part of the left thoracic duct (T5–T7), thus forming a single duct. The caudal aspect of the left thoracic duct involutes, while the proximal part of the right thoracic duct persists and drains the lymph from the right side of the head and neck, right arm, and upper thorax into the right jugular–subclavian confluence. The thoracic duct crosses the diaphragm through the aortic hiatus. As the thoracic duct ascends though the thorax, it receives multiple intercostal branches [1].
The cisterna chyli is an elongated lymphatic sac located over T12 to L2. It receives the lymphatic drainage of the right and left lumbar trunks carrying the lymph from the lower extremities. In addition, it receives the intestinal and intercostals trunks, carrying the lymph from the GI tract and lower chest wall, respectively (Fig. 23.1).
![A311788_1_En_23_Fig1_HTML.jpg](https://i0.wp.com/basicmedicalkey.com/wp-content/uploads/2017/06/A311788_1_En_23_Fig1_HTML.jpg?w=960)
![A311788_1_En_23_Fig1_HTML.jpg](https://i0.wp.com/basicmedicalkey.com/wp-content/uploads/2017/06/A311788_1_En_23_Fig1_HTML.jpg?w=960)
Fig. 23.1
![](https://freepngimg.com/download/social_media/63059-media-icons-telegram-twitter-blog-computer-social.png)
Superficial and deep lymphatics follow their respective venous counterparts. Lymph node stations are located at the site of joints in the extremities and anatomical functional units in the head and neck. Virtually 90 % of all the lymph drains into the thoracic duct. The right lymphatic duct drains the remainder, mostly from right half of the head and neck, upper right thorax, and right upper extremity. Eventually the entire body lymph is returned to the right atrium via the superior vena cava
![](https://freepngimg.com/download/social_media/63059-media-icons-telegram-twitter-blog-computer-social.png)
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