The retroauricular artery usually arises from the external carotid artery (in 93% of cases) and runs relatively deep,
passing through the parotid gland. It emerges in front of the anterior surface of the mastoid process behind the auricle. Because this artery lies 3 cm beneath the skin near the mastoid process, one might anticipate problems when preparing it for transfer. Inasmuch as the external diameter of this artery near the mastoid process is about 1.2 mm, however, we found that preparation was not difficult. Furthermore, the retroauricular artery rises upward abruptly at the mastoid process to a position 1 cm below the skin surface in the central portion of the posterior aspect of the auricle. It is therefore possible to expose this artery through careful dissection. It should be kept in mind that in 7% of cases, the retroauricular artery also arises from the occipital artery (Fig. 63.1A) (2, 3).

The retroauricular artery distributes some branches behind the auricle and supplies the flap area. The artery runs lateral and slightly posterior to the facial nerve trunk. Thus, with care, injury to this nerve during preparation of the flap can be avoided.

The relationship of the artery to the greater auricular nerve is not uniform. The retroauricular vein does not always accompany the artery. It courses in a more superficial zone, usually 1.5 cm below the skin surface of the mastoid region and 0.3 cm below the surface behind the auricle. The mean external diameter of the vein behind the auricle is 1.4 mm; it appears abruptly as it ascends above the auricle. The vein is situated in a posterosuperior position to the artery.