The Tear Trough Is a Ligament Story
Cadaveric work established that the tear trough deformity has a discrete anatomical basis: a true osteocutaneous ligament arising from the maxilla and inserting into skin, sitting between the palpebral and orbital parts of orbicularis oculi. The groove patients point to is the surface mark of that attachment — which is why it deepens with age as surrounding fat deflates around a fixed tether.
The correction logic follows directly. Filler does not erase a ligament; it disguises the transition around it, usually from the deep plane beneath the muscle. Understanding the trough as an attachment rather than a hollow explains both why superficial correction so often produces irregularity and why small deep volumes can achieve what larger superficial ones cannot.
The Fat Compartments Around the Trough
Deep to orbicularis lies the sub-orbicularis oculi fat, and below it the deep medial cheek fat — the compartment whose deflation drives much of midface ageing and whose supraperiosteal augmentation underpins modern cheek technique. Superficially, the malar fat contributes the cheek's visible volume. These compartments age at different rates, which is why midface correction is compartment strategy rather than general volumisation.
The pyriform region deserves its own mention: deep injection beside the nasal base lifts the ala and softens the nasolabial shadow, but the space is crossed by the angular artery's territory, making it one of the midface's highest-consequence deep pockets.
The Vessels: Infraorbital Bundle and Angular Artery
Two named structures organise vascular safety here. The infraorbital bundle exits its foramen roughly in line with the medial limbus a centimetre below the rim, fanning into the midface — a fixed exit point every deep injection in the region must respect. The angular artery runs near the medial canthus at the trough's medial end, where the facial artery's terminal course meets the orbit's own circulation.
The angular territory is also an anastomotic junction with the dorsal nasal system — a direct connection into the internal-carotid map that places medial tear-trough and pyriform injections on the routes described in the visual-loss literature. Depth and pressure discipline earn their keep at exactly these points.
Plane Logic, Cannulas and Newer Indications
The regional consensus is plane-based: deep, supraperiosteal placement beneath orbicularis for structural correction, typically cannula-delivered from lateral entry points that keep the tip away from the foramen and the angular territory; restraint above the muscle, where product shows and lymphatics congest. The thin periorbital skin forgives nothing placed too superficially.
Newer periorbital indications — polynucleotides and skin boosters beneath the eye — inherit the same anatomy with a different target layer: intradermal or immediately subdermal, above the vascular planes the structural work must respect. The products differ; the map does not. A clinician who can name the layer each product belongs to can move between indications without moving the risk.
As everywhere in the midface, the anatomy is learned most convincingly where it can be seen in depth: the trough's ligament, the SOOF, the foramen and the angular course are structures a dissection displays in true relationship — and dye in the deep plane shows precisely the space a cannula is meant to fill.