#Subclavian vein

#Origin and course

• continuation of the axillary vein where it crosses anteriorly to, and at the lateral border of, the first rib
  • this occurs along the subclavian groove of the first rib
  • the cephalic vein inserts into the axillary vein before it becomes the subclavian vein
• it crosses posterior to the clavicle at the midclavicular line
• it is anterior to the subclavian artery, separated by the anterior scalene muscle which inserts into 1st/2nd rib
• drainage into superior vena cava (SVC)
  • the right subclavian vein drains directly into the SVC
  • the left subclavian vein drains into the innomminate vein which crosses the midline and before draining into the SVC
  • these occur posterior to the sternoclavicular joint at the medial border of anterior scalene

OpenStax AnatPhys fig.20.38 - Thoracic Upper Limb Veins CC BY 4.0 via Wikimedia Commons

#Tributaries

• external jugular vein
• lymphatic ducts
  • the right lymphatic duct drains into the right subclavian vein
    • it receives lymph from the right arm, right hemithorax, and right side of the head and neck; totalling 25% of total body lymph drainage
  • the thoracic duct drains into the left subclavian vein
    • it receives the lymph from the remaining 75% of the body
• dorsal scapular veins
• anterior jugular veins

OpenStax AnatPhys fig.21.4 - Lymphatic Trunks and Ducts System CC BY 4.0

#Relations

Anterior

• clavicle
• subclavius muscle
• pec major

Posterior

• subclavian artery (posterior and superior to vein)
• anterior scalene muscle
• 1st rib and intercostal space
• phrenic nerve
• lung apex and pleura

Superior

• subclavian artery (posterior and superior to vein)
• clavicle
• neck muscles and platysma

Medial

• trachea
• carotid sheath and its contents

Lateral

• axillary vein
• inferior trunk of brachial plexus

Anatomy of the thoracic inlet by Nadezdha D. Kiriyak CC BY 4.0 via Wikimedia Commons

#Surface anatomy

• the deltopectoral groove is palpated, found at the lateral third of the clavicle
• a needle directed towards the sternal notch, posterior to the clavicle, and with a shallow angle of attack will meet the subclavian vein where it crosses posterior to the clavicle at the midclavicular line
• the subclavian vein can also be cannulated using a supraclavicular approach