Tissue type shapes how healing proceeds because different tissues have different cell sources and extracellular matrices that govern regenerative capacity and repair pathways. Epithelial tissues recover quickly through re-epithelialization: basal cells proliferate and migrate across the wound bed to restore the barrier, often with minimal scar and rapid closure. Connective tissues heal more slowly and mainly through fibroblast-driven deposition of collagen and extracellular matrix, forming scar tissue that gradually remodels to restore structure but not the exact original architecture. Bone healing is more complex and organized: after an initial inflammatory response, a soft callus forms with fibrocartilage, then a hard callus of woven bone bridges the fracture, and remodeling converts it to stronger lamellar bone over time. The other statements don’t fit because healing is not identical across tissues, and nervous or muscle tissues have more limited or different regenerative capacities than suggested. Nervous tissue has limited regeneration in the central nervous system, and skeletal muscle does have substantial regenerative potential through satellite cells, though it can be impaired by fibrosis.

Myositis ossificans is the infection—wait, not infection—that bone forming within muscle after a blunt muscle contusion. This happens when the initial bleeding and inflammation in the injured muscle trigger cells to differentiate into bone-forming cells, leading to heterotopic ossification. As this bone develops, it creates a firm mass, limits range of motion, and can cause persistent pain and functional loss. It’s considered a serious complication because it changes normal muscle tissue into bone and can require long-term management, sometimes even surgical removal after maturation if it severely restricts movement. Tendinopathy, by contrast, is a tendon disorder usually from overuse or degeneration, not a direct result of a single contusion. Muscle fatigue refers to temporary decline in performance from energy depletion. Nerve entrapment is a nerve compression issue and isn’t the classic direct complication of a muscle contusion.

Angiogenesis—the growth of new blood vessels—is central to building the tissue foundation needed for repair. It occurs most prominently during the proliferative (reparative) phase, when granulation tissue forms. In this phase endothelial cells proliferate and sprout to create new capillaries that permeate the wound bed, driven by signals such as VEGF in response to hypoxia. Those new vessels supply oxygen and nutrients to fuel fibroblast activity, collagen deposition, and epithelialization, all key features of this phase. Inflammation focuses on clearing debris and fighting infection, with blood vessels mainly delivering immune cells and plasma proteins. Remodeling then shifts toward reorganizing and strengthening the new tissue, with collagen maturation and scar refinement; vessels become less prominent as the wound gains strength. So while some vascular activity can occur earlier, the production of new blood vessels is a defining part of the proliferative phase.

Yellow flags are psychosocial factors that can impede recovery from pain. They reflect beliefs, emotions, and social influences that shape how a person experiences pain and sticks with treatment. Because these factors can foster fear, catastrophizing, avoidance, or poor coping, they are associated with a higher risk of persistent pain and disability if not addressed. This is why the true statement is that yellow flags denote psychosocial risk factors that hinder recovery. They are not indicators of pathology in the body, and they are distinct from red flags, which signal possible serious underlying disease. They don’t predict improved outcomes; rather, they help explain why recovery may be slower or less complete. Clinically, identifying yellow flags early guides interventions such as education, reassurance, graded activity, and psychological approaches to improve coping and adherence.