Anomalous course of the cervical carotid arteries. (Imaging Clinic).

An anomalous course of the carotid arteries in the neck is uncommon. When such an aberration does occur, the proximity of the arteries to the midline of the posterior portion of the pharynx can pose a risk during pharyngeal surgery. The case described here is that of a 26-year-old woman in whom an anomalous course of the carotid arteries in the retropharyngeal area was identified as an incidental finding.

Embryologically, the carotid arteries originate in the third aortic arch and the dorsal aorta. Normally, the dorsal aortic root descends into the chest by the 8th week of development, thereby straightening the course of the internal carotid artery. (1) It has been postulated that an incomplete straightening of the carotid vessels enables the embryonic angulation to persist. This leads to the formation of tortuous or aberrant internal carotid arteries in the retropharyngeal space. Anatomic descriptions of tortuous internal carotid arteries in the otolaryngology literature range from mild kinking to complete circular loops. As patients age, the development of atherosclerosis or hypertension can cause these malformations to become morepronounced, especially in the elderly. (1) These changes can also result in a widening of the prevertebral retropharyngeal soft tissues, which can be seen on plain radiographs of the cervical spine. (2)

An aberrant position and course of the carotid arteries can be clearly demonstrated on computed tomography (CT) (figure 1), digital angiography (figure 2), and magnetic resonance angiography. (3,4)

References

(1.) Shanley DJ. Bilateral aberrant cervical internal carotid arteries. Neuroradiology 1992;35:55-6.

(2.) Fix TJ, Daffner RH, Deeb ZL. Carotid transposition: Another cause of wide retropharyngeal soft tissues. AJR Am J Roentgenol 1996;167:1305-7.

(3.) Walsh DW, Ho YB, Borke RC, Rovira MJ. Anomalous course of the common carotid arteries: CT and MRA illustration--a case report. Angiology 1998;49:235-8.

(4.) Collazo-Ornes P, Figueroa RE, Escobar W. Anatomia y patologia de Ia region infrahioidea. In: Rodriguez-Carbajal J, Palacios E, Figueroa RE, eds. Neurorradiologia: Cabeza y Cuello. Philadelphia: Lippincott Williams & Wilkins, 1999:555-71.

From the Department of Radiology (Dr. Rojas and Dr. Palacios) and the Department of Otolaryngology (Dr. Hunt), Louisiana State University Health Science Center, New Orleans.