Abstract
- For trauma purposes the neck is divided into three distinct anatomical zones.
- Zone 1: from the sternal notch to the cricoid cartilage.
- Zone 2: from the cricoid cartilage to the angle of the mandible.
- Zone 3: from the angle of the mandible to the base of the skull.
- Zone 1: from the sternal notch to the cricoid cartilage.
- Knowing the contents of each zone is important when considering possible injuries.
- Zone 1: the major vessels of the upper mediastinum, the lung apices, esophagus, trachea, thoracic duct, and thyroid gland.
- Zone 2: the carotid sheath and contents, vertebral arteries, esophagus, trachea, pharynx, and the recurrent laryngeal nerve.
- Zone 3: distal carotid and vertebral arteries, distal jugular veins.
- Zone 1: the major vessels of the upper mediastinum, the lung apices, esophagus, trachea, thoracic duct, and thyroid gland.
- At the level of the superior border of the thyroid cartilage the common carotid artery bifurcates into the internal and external carotid arteries.
- At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve and the posterior belly of the digastric muscle.
- The external landmark of the pharyngoesophageal and laryngotracheal junctions is the cricoid cartilage. On esophagoscopy, this is located 15 cm from the upper incisor teeth.
- The cricothyroid membrane is four fingerbreadths above the sternal notch.
Surface Anatomy
For trauma purposes the neck is divided into three distinct anatomical zones.
Zone 1: from the sternal notch to the cricoid cartilage.
Zone 2: from the cricoid cartilage to the angle of the mandible.
Zone 3: from the angle of the mandible to the base of the skull.
Knowing the contents of each zone is important when considering possible injuries.
Zone 1: the major vessels of the upper mediastinum, the lung apices, esophagus, trachea, thoracic duct, and thyroid gland.
Zone 2: the carotid sheath and contents, vertebral arteries, esophagus, trachea, pharynx, and the recurrent laryngeal nerve.
Zone 3: distal carotid and vertebral arteries, distal jugular veins.
At the level of the superior border of the thyroid cartilage the common carotid artery bifurcates into the internal and external carotid arteries.
At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve and the posterior belly of the digastric muscle.
The external landmark of the pharyngoesophageal and laryngotracheal junctions is the cricoid cartilage. On esophagoscopy, this is located 15 cm from the upper incisor teeth.
The cricothyroid membrane is four fingerbreadths above the sternal notch.
General Principles
Overall, approximately 1/3 of all gunshot wounds and 1/5 of stab wounds to the neck result in significant injuries to vital structures. Transcervical gunshot wounds are associated with the highest incidence of significant injuries.
The incidence of tracheal or esophageal injury is approximately 10% for gunshot wounds and 5% for stab wounds.
Cervical spine injuries after penetrating trauma are extremely rare.
Patients with hard signs of vascular injury (pulsatile bleeding, large or expanding hematoma, bruit or thrill, and shock) or aerodigestive tract injury (massive hemoptysis or hematemesis, air bubbling from a wound) should proceed directly to the OR.
All remaining patients with soft signs of vascular injury (small and nonexpanding hematoma or minor bleeding) or aerodigestive tract injury (hoarseness, minor hemoptysis, or hematemesis) should undergo CT Angiography. Treatment is then based on the CT results and trajectory. In the case of equivocal CT results, the selective use of catheter-based angiography, endoscopy, and bronchoscopy can be utilized to rule out an injury. CT Angiography is the optimal screening imaging modality; it will decrease the number of negative neck explorations and allow targeted treatment of injuries.
Asymptomatic patients can have their wounds closed and be observed.
About 10% of patients with penetrating neck trauma present with airway compromise due to direct trauma to the larynx or trachea, or due to external compression by a large hematoma.
Establishing an airway is a critical first step. This can be a difficult and potentially dangerous procedure. Fiberoptic intubation may increase success rates, and decrease the chance of worsening a partial injury. If possible, these patients should be taken to the operating room for airway management. Equipment for a cricothyroidotomy should be available, and the surgeon ready to perform a surgical airway.
Bleeding from a deep penetrating injury to the neck may be controlled by direct digital pressure in the wound, or placement of a Foley catheter into the wound and inflation of the balloon with sterile water. For some injuries, multiple Foley catheters may be needed to obtain hemostasis.
