The right common carotid artery originates from the innominate (brachiocephalic) artery. The external landmark is the right sternoclavicular joint. The left common carotid artery originates directly from the aortic arch in the superior mediastinum.

The carotid sheath contains the common and internal carotid arteries, the internal jugular vein, and the vagus nerve. The internal jugular vein lies lateral and superficial to the common carotid artery and vagus nerve. The vagus nerve lies posteriorly, between the artery and the vein. On occasion the vagus nerve may be located anterior to the vessels.

Figure 8.1 Surface anatomy and key anatomical relationships of the carotid artery.

Figure 8.2 Carotid sheath contents. The carotid sheath contains the common carotid and internal carotid arteries medially, the internal jugular vein laterally, and the vagus nerve posteriorly between the vessels.

The carotid sheath and its contents are covered superficially by the platysma, anterior margin of the sternocleidomastoid muscle, and the omohyoid muscle. Deep to the vessels are the longus colli and longus capitis muscles. Medial to the carotid sheath is the esophagus and trachea.

At the level of the superior border of the thyroid cartilage, the common carotid artery bifurcates into the internal and external carotid arteries.

The facial vein crosses the carotid sheath superficially to enter the internal jugular vein at the level of the carotid bifurcation.

Figure 8.3 The facial vein is the anatomical landmark approximating the location of the carotid bifurcation deep to it. The facial vein is ligated and divided in order to mobilize the internal jugular vein laterally and provide exposure to the underlying carotid bifurcation.

The external carotid artery lies medial to the internal carotid artery for the majority of their course. The first branch of the external carotid artery is the superior thyroid artery located near the carotid bifurcation.

The internal carotid artery does not have any extracranial branches.

Figure 8.4 The external carotid lies medial to the internal carotid artery and gives several branches (the first branches are the superior thyroid and lingual arteries). The internal carotid artery has no extracranial branches. Note the hypoglossal nerve (yellow loop) crossing over the two arteries.

At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve (Cranial Nerve XII) and the posterior belly of the digastric muscle. The glossopharyngeal nerve (Cranial Nerve IX) passes in front of the internal carotid artery, above the hypoglossal nerve.

Figure 8.5 Distal carotid artery anatomy. At the angle of the mandible, the carotid arteries are crossed superficially by the hypoglossal nerve, the posterior belly of the digastric muscle, and the glossopharyngeal nerve.

The external carotid arteries terminate in the parotid gland, where they divide into the superficial temporal and maxillary arteries.

At the level of the skull base, the internal carotid arteries cross deep and medial to the external carotid arteries to enter the carotid canal behind the styloid process.

A preoperative neurologic examination should always be performed and documented.

Patients with neurologic deficits secondary to carotid artery injury have a poor prognosis. If the diagnosis is made early (within 4–6 hours) revascularization should be performed. Delayed revascularization can convert an ischemic infarct into a hemorrhagic infarct, leading to increased morbidity, and should therefore be avoided.

If technically possible, all common and internal carotid artery injuries should be repaired, as ligation is associated with a significant risk of stroke. Ligation may be considered in the comatose patient with delayed operation (>6 hours from injury) or if there is uncontrollable hemorrhage. Temporary shunt placement is a preferred method of damage control for these injuries.

Prophylactic shunting of the common or internal carotid arteries should be considered intraoperatively in patients requiring reconstruction with grafts.

Minor carotid injuries, such as small intimal tears, may be managed nonoperatively with antithrombotic therapy and imaging to document resolution.

Select patients with extremely proximal or distal carotid injuries may be best managed with angiographically placed stents.

The external carotid artery can be ligated without significant sequelae.

Systemic heparinization (100 u/kg) should be considered in patients with no other injuries. Alternatively, heparin saline solution (5,000 units in 100 mL normal saline) can be injected locally, both proximal and distal into the injured vessel.

Unilateral internal jugular vein injuries can be repaired if the patient’s condition allows, and there is no significant stenosis (<50%). However, unilateral ligation is well tolerated. If there are bilateral internal jugular vein injuries, at least one vein should be repaired.

Vascular repairs should be protected in the presence of tracheal or esophageal injuries with interposed tissue, usually the strap muscles.

Complete vascular tray, Fogarty catheters, a carotid shunt, and rummel tourniquets. As exposure of the mediastinal segment of the carotid arteries or internal jugular veins may be required, a chest tray, sternal saw, and sternal retractor should always be available. One percent of lidocaine should also be readily available for possible injection of the carotid body if necessary, as well as prosthetic graft materials (PTFE or Dacron) in the event that reconstruction requires a conduit.

Headlights and surgical loupes are strongly recommended.