Course of the STA : It begins deep within the parotid gland (the largest of the salivary glands), originating behind the mandibular neck. It gives off a branch to the parotid gland, and immediately afterward gives rise to the transverse facial artery, which supplies blood to part of the muscles and skin of the cheeks. It then passes behind the temporo-mandibular joint, crosses the zygomatic arch (the bony bridge between the zygomatic bone in front, which forms the cheekbones, and the temporal bone behind) and 3 to 5 cm above the zygomatic arch it becomes superficial. It is at this level, halfway up in front of the ear, that one can begin to feel its pulse beneath the skin. Its course then ascends toward the temples, where it divides into two terminal branches : an anterior frontal branch, which supplies blood to the forehead, eyelids, and supraorbital ridges, and a posterior parietal branch, which supplies blood to the skin of the skull anteriorly and laterally. It communicates with numerous other arteries of the face and skull, which can supplement its blood supply in the event of a deficit and vice versa. The portion that may be operated on for cosmetic reasons should involve only the very final part of its ascending subcutaneous course and its terminal branches. Its underlying course must always be preserved.
Cases in which this artery (STA) can be used surgically
- 1. This artery can be used by neurosurgeons to supply blood to the brain in patients with so-called “giant” intracranial aneurysms. It is estimated that approximately 4% of the general population has an aneurysm in a cerebral artery, of which 10% to 15% (dilatation > 7 mm) may rupture, leading to death or neurological sequelae, or no serious consequences in 20% of cases. Preventive treatment to eliminate these small aneurysms does not require the use of the STA.
“Giant” aneurysms (width equal to or greater than 25 mm) account for only 5% of all intracranial aneurysms. They have a high probability of fatal rupture. The preventive (high-risk) surgery involves clipping the aneurysm and temporarily occluding certain arteries that supply the brain. The STA is then used as a bypass to maintain proper blood flow to the brain. - 2. This artery can also be used by plastic surgeons to repair severe and/or serious cosmetic defects of the face (major trauma, extensive tumor resection, extensive burns, congenital deformities, etc.). In this context, the STA provides blood supply to skin flaps that cover the disfigured areas.
- 3. Moyamoya (“cloud of smoke” in Japanese) is a rare disease of the cerebral blood vessels caused by a slowly progressive narrowing or blockage of the carotid artery in the neck and its main branches. It affects children and young adults (<40 years old). In this context, STA can serve as a bridge between the healthy carotid artery (upstream of the blockage) and the arteries of the brain.
Cases where this artery is inflamed : Horton’s disease
It is an inflammation of the walls of large and medium-sized arteries, of unknown origin, which primarily affects people over 50 (average age 70) and is more common in women than in men. The STA is indurated on palpation. It is accompanied by a wide variety of possible symptoms, the most common of which are headaches localized to the temples, severe fatigue, weight loss, fever, and night sweats. Pain while chewing, though not always present, is characteristic. Without urgent treatment, this disease may lead to serious complications : blindness, stroke, and sometimes death.
Long-term corticosteroid therapy (prednisone) quickly brings the condition under control and protects patients from these complications. A biopsy involving the removal of a three-centimeter section of the artery at the temple confirms the diagnosis by revealing the presence in the arterial wall of characteristic giant cells.
