What does the azygos vein Do?
(Azygos vein labeled at bottom left.) The azygos vein is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood to the right atrium when either of the venae cavae is blocked.
What are the variants of the azygos system anatomy?
Variants of the azygos system anatomy occur frequently, especially the configuration of the hemiazygos and accessory hemiazygos veins. In some cases, the hemiazygos and accessory hemiazygos vein form a common trunk instead of draining separately into the azygos vein.
What is the meaning of azygos?
1. any unpaired part, as the azygos vein. 2. unpaired. Called also azygous. azygos vein. a vein beginning in the abdomen and coursing in the dorsal mediastinum which returns blood from the thorax to the heart. The right azygos is found in most domestic animals (rarely the pig) while the left azygos is found in pigs and ruminants.
What are the tributaries of the azygos?
This system consists of the azygos vein and its two main tributaries: the hemiazygos vein and the accessory hemiazygos vein. This article will discuss the anatomical course, relations and variations of the azygos vein as well as its tributaries. This will be followed by a discussion of any related clinical pathology.
What is the function of the azygos vein?
The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein.
What is unique about the azygos vein?
Azygos vein is the vein that drains the venous blood from the upper part of the posterior abdominal wall and the thoracic wall. It is very important for the reason that it connects the superior vena cava with the inferior vena cava, and it has very few to no valves.
Where is the Azygous vein?
The azygos vein originates at the junction of the right ascending lumbar and subcostal veins, entering the chest through the aortic hiatus. It ascends along the anterolateral surface of the thoracic vertebrae and arches ventrally to the right main bronchus at T5–T6, draining into the SVC.
What happens if the azygos vein is blocked?
Blockages below the azygos prevent any flow of blood to the heart via the SVC. However, in this case, blood will be redirected into the azygous vein and azygous system in a retrograde manner (Fig. 11).
Does everyone have an azygos vein?
Congenital defects To compensate for this congenital abnormality, the azygos vein dilates in order to accommodate for the increase in blood flow. It occurs in 0.3% of the population and is associated with congenital heart disease or asplenia syndromes (syndromes with an absence of normal spleen function).
What is the longest vein in the body?
Great Saphenous VeinWhat is the Longest Vein in the Body? Did you know that your Great Saphenous Vein is the longest vein in the human body? Extending from the top of your foot to the upper thigh and groin, THIS vein is the major culprit that causes Varicose Veins.
What does the azygos vein receive?
The azygos vein receives the lower eight right-sided posterior intercostal veins, as well as the bronchial veins from the right lung. It is joined by the right superior intercostal vein superiorly.
What veins drain directly into the azygos vein?
The major tributaries of the azygos vein are the right intercostal veins (excluding the right supreme (first) intercostal vein that drains into the right brachiocephalic vein), the right superior intercostal vein (usually formed by the union of the second to fourth intercostal veins), the right ascending lumbar and ...
How do you say azygos?
0:051:01How To Say Azygos - YouTubeYouTubeStart of suggested clipEnd of suggested clipInsiders 'insiders' 'insiders' e insights e insights insiders.MoreInsiders 'insiders' 'insiders' e insights e insights insiders.
Which veins are part of the azygos system quizlet?
What does the azygos system include? Azygos vein, hemiazygos vein and the accessory hemiazygos vein. Blood from the abdominal wall and thoracic cavity and delivers it to the superior vena cava. You just studied 12 terms!
What does the azygos vein drain dog?
The azygos vein is a vascular structure of extreme importance that drains blood from the posterior walls of the thorax and abdomen and unites the superior vena cava (SVC) to the inferior vena cava (IVC).
What veins drain directly into the azygos vein?
The major tributaries of the azygos vein are the right intercostal veins (excluding the right supreme (first) intercostal vein that drains into the right brachiocephalic vein), the right superior intercostal vein (usually formed by the union of the second to fourth intercostal veins), the right ascending lumbar and ...
Where is the Azygos vein?
The azygos vein is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood to the right atrium when either of the venae cavae is blocked.
Where does the Azygos vein originate?
The azygos vein generally begins at the level of the lumbar verte brae but may originate above the point in some cases. The lumbar aspect of the azygos vein can ascend anteriorly to the lumbar vertebrae and pass behind the right crus of the diaphragm or cross the aortic hiatus (where the aorta pierces the diaphragm) to the right of the cisterna chyli, a dilated lymph sac. The common trunk of the right ascending lumbar vein and the right subcostal vein join the azygos vein anterior to the body of T12. However, if the lumbar segment is absent, this trunk may form the azygos vein.
What veins form when the lumbar segment is absent?
However, if the lumbar segment is absent, this trunk may form the azygos vein. Structure and location of Azygos vein. It has been proposed that the azygos vein develops by originally draining to the posterior cardinal vein and then to the longitudinal venous channel.
How to diagnose azygos vein?
Azygos and hemiazygos continuation of the inferior vena cava (IVC) was not common in daily life. It is very hard to observe, particularly when it is not associated with congenital heart disease or deep venous thrombosis. Thus, it is crucial to diagnose the enlarged azygos vein at the confluence with the superior vena cava and in the retrocrural space to prevent misdiagnosis as a right-sided paratracheal mass. The loss of the intrahepatic segment of IVC with azygous and hemiazygos continuation happens in 0.6% of patients diagnosed for congenital heart disease and usually occurs simultaneously with situs inversus, asplenia, or polysplenia, persistent left superior vena cava (SVC), and congenital pulmonary venolobar syndrome. Azygos and hemiazygos continuation of the IVC is rare especially when it is not associated with congenital heart disease.
What is the name of the vein that drains the bronchial veins?
The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein. The anatomy of this blood vessel can be quite variable. In some rare variations, for example, it also drains thoracic veins, bronchial veins, and even gonadal veins. The vein is so named because it has no symmetrically equivalent vein on the left side of the body.
Why is the Azygos vein so named?
The vein is so named because it has no symmetrically equivalent vein on the left side of the body. The azygos system is considered to be the azygos vein located from rib number 2 to rib number 4, while on the left part of the body, the hemiazygos vein and the accessory hemiazygos vein together form the analogous venous system.
Which veins are left sided?
The azygos system of veins is considered to be the azygos vein, along with its left-sided counterparts, the hemiazygos vein and the accessory hemiazygos vein. It also creates a cavo-caval anastomosis by offering an alternative, collateral blood flow from the lower half of the body to the superior vena cava, bypassing the inferior vena cava. This can have clinical significance in any blood flow restriction of the inferior vena cava.
Where is the Azygos vein?
The azygos vein is a singular blood vessel of the torso that ascends on a course just to the right of the spine. It’s part of the system that drains blood from the mediastinum (the tissues between your lungs), as well as parts of the back and abdominal walls. Arising in the mid-low back, it bends around the hilum of the lungs and passes through the diaphragm before piercing the pericardium of the heart. 1
Which veins form a trunk before joining the Azygos vein?
The hemiazygos and accessory hemiazygos veins form a common trunk before joining the azygos vein.
What causes azygos vein to bleed?
Laceration (deep cut or tear) and bleeding of this internal vein is a clinical concern, and it can be affected by obstructions of surrounding veins, among other conditions. In very rare cases, congenital abnormalities affect the development of the azygos vein, something associated with some types of heart disease or asplenia (absence of the spleen). 1
What happens when the inferior vena cava is obstructed?
As a result, lesions can form in the vein, and an insufficient amount of blood is able to return to the heart. 3 Breathing problems, swelling, cognitive issues, and heart arrhythmia are among the symptoms.
How many tributaries does the Azygos vein have?
The azygos vein also has two tributaries (branches of the main vein): 1
What happens when blood flow from the superior vena cava to the right atrium of the heart is obst?
When blood flow from the superior vena cava to the right atrium of the heart is obstructed, an insufficient amount from the head and neck is drained. This can cause blood flow to reverse—to move away from the heart—leading to breathing problems, lightheadedness, and swelling. 3
Where is the accessory hemiazygos vein?
Accessory hemiazygos vein: Draining the superior left hemithorax as well as veins of the esophagus, the accessory hemiazygos vein descends to the left of the spinal column. It crosses over to join the azygos vein, or sometimes the hemiazygos vein, at the seventh vertebra.
Where is the Azygos vein located?
The azygos vein is a unilateral vessel that ascends in the thorax to the right of the vertebral column, carrying deoxygenated blood from the posterior chest and abdominal walls. It forms part of the azygos venous system.
Which vein drains into the azygos vein?
hemiazygos vein is a similar structure on the opposite side of the vertebral column and drains into the azygos vein. accessory hemiazy gos vein. posterior right intercostal veins. right superior phrenic vein. right superior intercostal vein.
What is the azygos arch?
This arch of the azygos vein ( arcus venae azygos) is an important anatomical landmark. Often there is a valve in the arch within 4 cm of its orifice in the SVC, which can be seen in about two-thirds of CT cases with reflux of contrast into the azygos arch 2.
What does "azygous" mean?
Azygous is a word in English meaning 'without pair', but in the context of anatomy, azygos vein is the sole correct spelling (see Terminologia Anatomica ).
Where does the Azygos vein enter the chest?
If originating at a lumbar level, the azygos vein typically enters the chest through the aortic hiatus (T12 vertebral level), although may enter by piercing the right crus of the diaphragm.
Which vein freely anastomoses with the vertebral venous plexus?
The azygos vein freely anastomoses with the vertebral venous plexus.
Overview
The azygos vein is a vein running up the right side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood to the right atrium when either of the venae cavae is blocked.
Structure
The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein.
It is formed by the union of the ascending lumbar veins with the right subcostal veins at the level of the 12th thoracic vertebra, ascending to the right of the descending aorta and thoracic duct, passing behind the right crus of diaphragm, anterior to the vertebral bodies of T12 to T5 and righ…
Function
The azygos system of veins is considered to be the azygos vein, along with its left-sided counterparts, the hemiazygos vein and the accessory hemiazygos vein. It also creates a cavo-caval anastomosis by offering an alternative, collateral blood flow from the lower half of the body to the superior vena cava, bypassing the inferior vena cava. This can have clinical significance in any blood flow restriction of the inferior vena cava.
Clinical significance
Azygos vein abnormalities can be suggested on chest radiograph by enlargement of the azygos shadow to greater than 1 cm. False positives can occur in heart failure causing increased pressures on the right side of the heart, or adjacent lymphadenopathy. Azygos and hemiazygos continuation of the inferior vena cava (IVC) was not common in daily life. It is very hard to observe, particularly when it is not associated with congenital heart disease or deep venous thro…
History
The Greek root zyg refers to a pair. 'A-' means not. Thus, azygos means unpaired. The azygos vein is unpaired in that there is only one in the body, mostly on the right side. While there is the hemiazygos vein and its accessory on the left side of the body, they are considered tributaries of the azygos vein rather than its left-side equivalent.
This terminology is only accurate in some species, such as the human, dog, and cat. Ruminants …
Additional images
• Diagram showing completion of development of the parietal veins.
• The venæ cavæ and azygos veins, with their tributaries.
• Mediastinal surface of right lung.
• Azygos vein
See also
• Hemiazygos vein
• Posterior intercostal veins
• Superior vena cava
• Chronic cerebrospinal venous insufficiency
External links
• Anatomy figure: 19:03-03 at Human Anatomy Online, SUNY Downstate Medical Center - "Right side of the mediastinum."
• Dissection at lumc.edu
• Radiology at umich.edu
• Function at Knowyourbody.net
Terminology
Gross Anatomy
- Along with the hemiazygos and accessory hemiazygos veins, the azygos vein is part of what’s called the azygos system. Primarily, this system is tasked with carrying blood from the walls of the upper abdomen as well as the upper portion of the lower back (the upper lumbar region) back to the heart. It also drains the mediastinum, the tissues between...
Radiographic Features
Variant Anatomy
History and Etymology
- The azygos vein is formed by the union of the right ascending lumbar veinand right subcostal veins at around the T12-L2 vertebral level. If originating at a lumbar level, the azygos vein typically enters the chest through the aortic hiatus (T12 vertebral level), although may enter by piercing the right crus of the diaphragm. It then ascends in the ...
Related Pathology
- It forms part of the normal cardiomediastinalcontouron chest x-rays and normally measures <7 mm (erect projection).