A 28-year-old woman sustains a laceration over the dorsum of her hand during a motor vehicle accident. The wound is cleaned and sutured in the emergency department. Which of the following events occurs predominantly during the first 48–72 hours of wound healing?

Explanation

## Phases of Wound Healing Timeline Wound healing progresses through distinct overlapping phases with characteristic events at specific timepoints: ### Inflammatory Phase (0–72 hours) - **Hemostasis (0–10 minutes):** Platelet aggregation, fibrin clot formation - **Inflammatory response (hours 0–3 onwards):** Increased vascular permeability mediated by histamine, bradykinin, and prostaglandins - **Neutrophil infiltration (peak at 24–48 hours):** First responders to clear bacteria and debris; peak by 48–72 hours - **Macrophage recruitment (begins ~24 hours, peaks ~3–5 days):** Phagocytosis, growth factor secretion ### Proliferative Phase (3–21 days) - Fibroblast proliferation and collagen synthesis (begins ~day 3, peaks ~day 5–7) - Angiogenesis (begins ~day 3) - Epithelialization (begins within hours, continues through proliferative phase) ### Remodeling Phase (weeks 3–months/years) - Collagen cross-linking and maturation - Scar formation **Key Point:** The **first 48–72 hours** is dominated by the inflammatory phase, characterized by **increased vascular permeability** (allowing fluid and cell extravasation) and **neutrophil infiltration** (the hallmark of acute inflammation). This is the correct answer. **Clinical Pearl:** Neutrophils are the predominant cell type in the first 48 hours; macrophages become more prominent after 48–72 hours and persist longer.