[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Chest](https://durgical.com/en/anatomy/region/chest/) › Superior vena cava [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Superior vena cava The superior vena cava is the large vein that returns oxygen-poor blood from the head, neck, arms and upper [chest](https://durgical.com/en/anatomy/region/chest/) to the right atrium. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=superior_vena_cava&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The large vein bringing blood from the head, neck and arms into the right atrium. ## What it does Returns oxygen-poor blood from the upper body. Pacemaker leads and central lines pass through it. ## Key points - The azygos vein arches over the right lung root and enters it from behind at the sternal angle level (T4–T5), just before the cava enters the [pericardium](https://durgical.com/en/anatomy/pericardium/) - Upper half in the superior mediastinum, lower half inside the fibrous pericardium in the middle mediastinum - Blockage above the azygos inflow lets blood bypass through the azygos to the cava; blockage below it forces flow down to the [inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/), with more marked collaterals - The sinoatrial node lies at its junction with the right atrium, at the top of the crista terminalis ## Key facts **Drains** Head, neck, upper limbs and chest wall, via both [brachiocephalic veins](https://durgical.com/en/anatomy/brachiocephalic-vein/) and azygos vein; formed behind right 1st costal cartilage **Into** Right atrium at level of right 3rd costal cartilage; valveless ## Relations **Course** Formed behind the right 1st [costal cartilage](https://durgical.com/en/anatomy/costal-cartilage/), it descends vertically along the right sternal border, receives the [azygos vein](https://durgical.com/en/anatomy/azygos-vein/) at the 2nd costal cartilage level and enters the [right atrium](https://durgical.com/en/anatomy/right-atrium/) at the 3rd **In front** Anterior margins of the right lung and [pleura](https://durgical.com/en/anatomy/pleura/), the thymic remnant, and the right 1st and 2nd costal cartilages and intercostal space **Behind** [Trachea](https://durgical.com/en/anatomy/trachea/) and right [vagus nerve](https://durgical.com/en/anatomy/vagus-nerve/) above; the right lung root ([right pulmonary artery](https://durgical.com/en/anatomy/right-pulmonary-artery/) and [right main bronchus](https://durgical.com/en/anatomy/right-main-bronchus/)) below **Medial** [Ascending aorta](https://durgical.com/en/anatomy/ascending-aorta/) and [brachiocephalic trunk](https://durgical.com/en/anatomy/brachiocephalic-trunk/) **Lateral** Right [phrenic nerve](https://durgical.com/en/anatomy/phrenic-nerve/) with the pericardiacophrenic vessels, then the mediastinal pleura and right lung ## How to find it Not palpable. Its line on the chest wall runs along the right edge of the [sternum](https://durgical.com/en/anatomy/sternum/), from behind the right 1st costal cartilage, where the two brachiocephalic veins join, down to the right 3rd costal cartilage, where it opens into the right atrium. ## On imaging On a frontal chest X-ray it forms the upper right mediastinal border. The carina is used as a landmark for central catheter tips, which are aimed at the lower cava or its junction with the right atrium. Contrast CT shows obstruction, thrombus and collateral veins. ## Common problems - Superior vena cava syndrome: blockage by a tumour or clot, causing swelling of the face and arms. ## Clinical notes - Superior vena cava syndrome is caused mostly by lung cancer and then lymphoma; clots around catheters and pacemaker leads are an increasing cause - Signs: swollen face and arms, distended neck and chest-wall veins, worse lying flat or bending forward; raising both arms can bring on facial plethora (Pemberton sign) - Route for central venous catheters, pacemaker and defibrillator leads and right heart catheterization from the neck or arm - Cannulated for cardiopulmonary bypass; stitches or clamps near the cavoatrial junction can damage the sinoatrial node ## Anatomical variants - Persistent left superior vena cava in about 0.3% of people (more often with congenital heart disease), usually draining into an enlarged [coronary sinus](https://durgical.com/en/anatomy/coronary-sinus/); rarely it opens into the [left atrium](https://durgical.com/en/anatomy/left-atrium/), a right-to-left shunt that can carry paradoxical emboli - Double superior vena cava (right and persistent left), with or without a bridging left brachiocephalic vein ## Development Forms from the right anterior cardinal vein and the right common cardinal vein; the left-sided equivalents normally regress, leaving the coronary sinus and the oblique vein of the left atrium. ## Related conditions - [Superior vena cava syndrome](https://durgical.com/en/conditions/superior-vena-cava-syndrome/) - [Hypovolaemic shock](https://durgical.com/en/conditions/hypovolaemic-shock/) - [Pneumothorax](https://durgical.com/en/conditions/pneumothorax/) - [Cardiac tamponade](https://durgical.com/en/conditions/cardiac-tamponade/) - [Lung cancer](https://durgical.com/en/conditions/lung-cancer/) ## Test yourself Think of the answer, then tap the question to see it. ## Where is the superior vena cava formed, and where does it enter the right atrium? It forms behind the right 1st costal cartilage and enters the right atrium at the level of the right 3rd costal cartilage. ## Which vein joins the superior vena cava from behind, and at what level? The azygos vein, arching over the right lung root at the sternal angle level (T4–T5). ## What are the main causes of superior vena cava syndrome? Mostly lung cancer, then lymphoma; clots around catheters and pacemaker leads are an increasing cause. ## What is the Pemberton sign in superior vena cava obstruction? Facial plethora brought on by raising both arms. ## Which conduction structure lies at the junction of the superior vena cava with the right atrium? The sinoatrial node, at the top of the crista terminalis; stitches or clamps near the cavoatrial junction can damage it. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/superior-vena-cava/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** vena cava superior TA2 4745 **Official Spanish (DeCS)** Vena cava superior DeCS D014683 **English (TA2)** Superior vena cava **Also called** vena cava cranialis ## Related - [Sinoatrial (SA) node](https://durgical.com/en/anatomy/sinuatrial-node/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=15085); [Anatomy, Thorax, Superior Vena Cava](https://www.ncbi.nlm.nih.gov/books/NBK545255/); Anatomy of the Human Body (20th ed.): Surface Markings of the Thorax (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain; Tratado de anatomía humana (9.ª ed.), tomo II, Libro IV Angiología, sección 4: Venas (sistemas de las venas cavas superior e inferior, vena porta, venas del raquis). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/superior-vena-cava/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/superior-vena-cava/