Table 1.

Anatomical definitions of zones of penetrating neck injury and anatomical structures at risk

Zone	Anatomical boundaries	Anatomical structures at risk
3	Superior boundary: skull base Inferior boundary: angle of the mandible	Pharynx Carotid arteries Internal jugular veins Cranial nerves Sympathetic chain Parotid gland
2	Superior boundary: angle of the mandible Inferior boundary: cricoid cartilage	Laryngotracheal complex Pharynx Oesophagus Carotid artery Jugular veins Vertebral arteries Spinal cord Vagus and phrenic nerves
1	Superior boundary: cricoid cartilage Inferior boundary: clavicles	Trachea Oesophagus Carotid artery Jugular veins Thoracic duct Spinal cord Cranial nerves Vertebral arteries