Anaes · Applied anatomy

Neck anatomy and central venous access

Also known as Neck anatomy · Carotid sheath · Internal jugular vein · Central venous access · Subclavian vein · CVC insertion

The neck carries the great vessels that the anaesthetist cannulates for central venous access and arterial monitoring, the central airway that is the target of intubation and tracheostomy, and the nerves of regional blocks. The framework rests on six exam-critical ideas. First, the neck is divided by the sternocleidomastoid muscle into an anterior triangle (containing the carotid sheath, thyroid, larynx and trachea) and a posterior triangle (containing the brachial plexus and the subclavian vessels); the carotid sheath is the key structure for central venous access. Second, the CAROTID SHEATH contains, from medial to lateral/posterior, the common and internal carotid arteries, the internal jugular vein (lateral), and the vagus nerve (between and posterior); the deep cervical chain of lymph nodes lies along the sheath and the ansa cervicalis is embedded in its anterior wall. Third, the INTERNAL JUGULAR VEIN runs deep to the sternocleidomastoid from the jugular foramen to join the subclavian vein behind the sternoclavicular joint to form the brachiocephalic vein; it lies lateral to the carotid artery with the vagus nerve between them, and is the workhorse of ultrasound-guided central access. Fourth, the SUBCLAVIAN VEIN runs just below the clavicle (its curve makes it a 'safe' route away from the chest wall), anterior to the anterior scalene muscle which separates it from the subclavian ARTERY behind; the dome of the pleura and the apical lung lie behind and above both, the anatomical basis of pneumothorax. Fifth, the right INTERNAL JUGULAR and right SUBCLAVIAN routes are preferred because the right brachiocephalic vein is short and vertical (a straight path to the SVC) and the right thoracic duct is absent (the main thoracic duct drains on the LEFT); a LEFT internal-jugular or subclavian line risks injuring the thoracic duct and causing chylothorax. Sixth, the complications of central access are all anatomical — arterial puncture (the carotid or subclavian artery), pneumothorax (the apical pleura), nerve injury (the vagus, phrenic or brachial plexus), chylothorax (the thoracic duct on the left), air embolism (a negative-pressure vein entraining air), and catheter misplacement or malposition — which is why real-time ultrasound guidance and careful technique are now standard. Built on the ultrasound-guided IJV-cannulation study (Amatya 2025), the cervical-plexus-block study (Shrestha 2025), the thoracic-duct-and-brachial-plexus study (de Oliveira 2026), the bedside-tracheostomy study (Locatello 2026), the external-jugular-vein-absence case report (Hamasaki 2026), the carotid-artery-variation study (Lee 2026), the IJV-collapsibility study (Arora 2026), and the cerebral-air-embolism case report (Rundblad 2026), the IJV-variation cannulation study (Lorchirachoonkul 2012), and the cervical-vagus-variation ultrasound study (Randhawa 2025).