When injecting the depressor anguli oris (DAO), depth isn’t just important — it’s protective. The depressor labii inferioris muscle lies beneath the DAO, attaching to the bone. If your injection is too deep and low, you risk hitting the wrong muscle — a common cause of lower lip ptosis. ❌ ✅ The safer, more effective approach? Injecting more superiorly and superficially, keeping your toxin in the correct plane and away from the DLI. Understanding the anatomical layering here helps you avoid compl

The depressor labii inferioris (DLI) is a small muscle with a big impact on smile dynamics. 🔎 What injectors need to know: Function: pulls the lower lip outward. Clinical sign: in patients with a strong DLI, the smile can expose all lower teeth (think “wide lateral pull”). Treatment: precise toxin placement can balance lip movement, soften excessive lower tooth show, and harmonize smile aesthetics. 💡 Injector tip: Always assess smile patterns before treating the DLI, over-relaxation risks asym