Anatomic variations of the superficial temporal artery

The superficial temporal artery (STA) is a terminal branch of the external carotid artery. It is commonly described as coursing posterior to the mandibular condyle and over the posterior zygomatic root (PZR) and then dividing terminally into parietal and frontal branches. However, possible variations of the main trunk of the STA have seemingly been overlooked. This study retrospectively examined the archived head tomography angiograms of 43 patients to determine the morphology and topography of the STA prior to its terminal bifurcation. In 79% of patients, the STA topography related to the mandibular condyle was bilaterally symmetrical, either retrocondylar (65.1%) or laterocondylar (13.6%). The parietal branch was sometimes absent unilaterally (16.3%) or bilaterally (9.3%). In 2/43 cases, the frontal branch of the STA was unilaterally absent. When both terminal branches were present, the bifurcation was retrocondylar or immediately above the PZR when on the PZR, or the terminal division of the STA was high above the PZR. In 88.4% of the STAs, different patterns of kinking and coiling were documented, including retrocondylar kinks (27.9%), laterocondylar kinks (20.9%), kinks placed on the PZR (81.4%) and variably oriented suprazygomatic kinks (32.6%). Five of the 86 STAs were coiled, one retrocondylar, one laterocondylar, and three other placed on the PZR. Two cases showed unilateral pseudoaneurysms of the STA, one above the PZR and the other on the temporomandibular joint. The STA is surgically important; therefore, the number of anatomical studies of the STA should increase.