Upper face injection anatomy: forehead, glabella, temple
Forehead, glabella and temple: the region with the most predictable muscles and the most dangerous arteries.
The upper face is the paradox of injectable practice. For botulinum toxin it is the most predictable region on the face. For filler it is among the most dangerous.
Muscles
Frontalis elevates the brow. It is the sole elevator, which is the fact that governs everything about treating it. Corrugator supercilii draws the brows medially and downward. Procerus pulls the medial brow down. Orbicularis oculi closes the eye; its lateral fibres produce crow’s feet.
Because there is no second brow elevator, over-treating frontalis drops the brow with nothing available to compensate. The result is a heavy, hooded look that cannot be corrected except by waiting.
The corrugator complex sits close to the levator palpebrae superioris, and diffusion across that short distance is the mechanism of post-treatment ptosis. This is why glabellar technique specifies distance from the orbital rim rather than leaving placement to judgement, and why dilution matters here more than almost anywhere.
Arteries
The supratrochlear and supraorbital arteries emerge at the superior orbital rim and ascend into the forehead. They are terminal branches of the ophthalmic artery — internal carotid territory, in direct continuity with the retinal supply.
This is why the glabella and forehead together account for roughly half of all reported cases of filler-induced blindness. The vessels are small, which means a very small volume can fill them; the supratrochlear artery from glabella to orbital apex holds about 0.085 mL.
Depth offers less protection than commonly assumed. The supratrochlear artery becomes more superficial as it ascends, but its course at the rim is deep, and it varies between individuals and between sides.
The temple
Anatomically layered and genuinely hazardous. The superficial temporal artery and the zygomatico-orbital artery are implicated in reported blindness; the middle temporal vein has been associated with pulmonary embolism. Imaging studies of the region recommend ultrasound guidance, careful plane selection and individualised planning rather than generic landmarks.
Practical implications
- Toxin here is predictable but unforgiving of over-treatment; frontalis has no backup.
- Filler here demands small aliquots, low pressure and a clear reason for choosing the region.
- Cannula in preference to needle where the technique permits.
- Hyaluronidase available before starting, without exception.
