The Anatomy of a Safer Injection: A Story of Three Arteries and the Art of the Cheek
There is a deep wisdom in knowing the landscape of the face before you ever pick up a needle or a cannula. The most profound insight any injector can develop is this: the face is not a blank canvas, but a map of rivers and valleys. Three major arteries—the transverse facial, the facial, and the infraorbital—all rise from the great carotid, and to navigate them safely is to master both technique and reverence.
Let us begin with the transverse facial artery. You can find its origin by drawing a line straight down from the lateral canthus of the eye. This artery branches off the major carotid, passing under the gonial angle, rising over the parotid gland, and then weaving beneath the zygomatic bone. Here is the first piece of good news: in this region, the smaller branches arborize with veins. If you inadvertently inject into them, you may cause only minor bruising—no real damage. This is a safer zone.
Now, how best to inject the cheek in this area? The safer technique is not always the one you might assume. Many advanced practitioners advocate using a cannula swept from one direction or another. But let me share a truth born from experience: for true safety here, I would use a needle placed directly at a 90-degree angle onto the bone. Why? Because as long as you stay on the bone, you are not in line with the transverse facial artery. A cannula, surprisingly, does not guarantee safety. In fact, studies over the last three years have shown that most new cases of necrosis or blindness on the face are caused by cannulas. If you must use a cannula, ensure it is 25 gauge or thicker. But for this zone, a needle at 90 degrees minimizes bruising and maximizes safety.
Now, we turn to the facial artery, which also branches from the carotid and rises to the jawline. How do you find it with confidence? Ask your model to clench their jaw—the prominent muscle is your master muscle. Directly in front of it, you will feel a notch right on the bone. That notch is carved by the pulse of this artery since birth. It is deep and bound tightly to the bone. And this artery, from its origin to about this location, remains deep. Watch its path: it is always tortuous, winding like a river. Why? So that when we open our mouth, the artery can stretch without pinching. If it were straight, every movement would risk blanching. So this winding is a stroke of evolutionary protection.
Here is a critical landmark: two muscles lie over this deep facial artery—the risorius and the zygomaticus major. They rest on top of the artery, creating a safe superficial zone. As long as you stay in the superficial layer in this region, you are safe. But the zygomaticus minor muscle, which aligns just to the edge of the bone down to the mouth, is crossed by the artery—sometimes over, sometimes under. That is my cutoff point. If I must inject anywhere medial to that line, I switch to superficial approach. Everywhere else, I change my line of fire.
Let me teach you a simple marking: take a marker, start from under the zygomatic bone, and draw a line straight down to the lateral iris of the eye. That line is your safety boundary. Everything lateral to it? Stay deep. Everything medial? You must stay superficial. Now, consider the nasolabial fold. The facial artery often runs right along that fold. So when you are anywhere medial from the lateral iris, you are in a zone where the artery runs superficially. The rule reverses: here, to avoid it, you must stay deep. So the landmark teaches you: this area deep, that area superficial, and you avoid major complications.
And finally, the infraorbital artery. It runs just under the inner iris. To pinpoint it: find the inner iris, drop down to the orbital rim, and then go 8 to 11 millimeters below. It lies parallel to the supraorbital artery, which you can feel as another notch. This infraorbital artery runs deep and then angles upward at 45 degrees. There is a groove that directs everything toward it. So what do I strongly advise? Never inject from below with a needle or cannula to deposit product here—that groove will guide your needle straight into the artery. The good news: a bony hub protects the artery from above. So if you come in from a lateral angle—starting just outside that safety line, staying deep—you are protected. Even if you touch the facial artery (which at this point becomes the angular artery), it always stays superficial. So by staying deep, you avoid it, and the bony hub protects the infraorbital. Come in laterally, stay deep, deposit, and you are fine.
I often hear the question: "How do I avoid hitting the facial artery when injecting the jawline?" Many use a cannula going in one direction or another. The safest method: find that notch at the jaw, pinch the skin up, make your mark superficially, enter at an angle, then move your cannula away from the danger zone. Same going backwards. Enter, move away, and you will not hit that artery.
Finally, the premaxilla—the A-line. As we mature, the center of the face protrudes, creating retrusion. To restore volume balance, we often need to add volume at the A-line. But the facial artery runs right up to that line. What to do? You can go through the artery with a fine needle safely—there is no danger if you simply pass through. The real risk is depositing into the lumen. So go down to the bone at a 45-degree angle facing the corner of the mouth, and you will be fine.
Let us recap by drawing the map once more: this region: deep. This region: superficial. This region: deep. And this entry point: superficial, then lay deep, going that way. That entry: the same. Follow these boundaries, respect the rivers, and your art will be both beautiful and safe.