Which statement about fracture callus features is true?

• A. Intertrabecular spaces are highly cellular
• B. Atypical mitoses are common
• C. Fracture callus shows reactive osteoblasts with abundant cytoplasm and mild anisokaryosis; no marked pleomorphism
• D. Osteoclasts are absent

Answer: (C)

During fracture healing, the callus forms a reparative, benign tissue where osteoblasts at the margins are actively producing osteoid and laying down new woven bone. These reactive osteoblasts have abundant cytoplasm from intense synthetic activity, and their nuclei may show mild variation in size (anisokaryosis) but should not have marked pleomorphism or atypical mitoses. This pattern reflects normal reparative growth rather than malignancy. Osteoclasts are part of the remodeling process, resorbing and reshaping the callus, so saying they are absent would not fit the healing scenario. Descriptions of very high cellularity in intertrabecular spaces or frequent atypical mitoses would point away from typical fracture repair and toward other pathologies. So the true statement is that fracture callus shows reactive osteoblasts with abundant cytoplasm and mild anisokaryosis, with no marked pleomorphism.