After a blood clot forms, which arteries undergo vasospasm causing the death of osteoblasts outside of the original break zone?

After a blood clot forms, which arteries undergo vasospasm causing the death of osteoblasts outside of the original break zone?

• A. Haversian arteries
• B. Central arteries
• C. Volkmann's arteries
• D. Nutrient arteries

Answer: (A)

The blood supply inside cortical bone comes from the Haversian system, where central arteries run through the Haversian canals to nourish the osteoblasts and osteocytes in the surrounding lamellae. After a fracture, a clot forms and a vasospastic response can narrow these intramedullary cortical vessels. When the Haversian arteries go into spasm, perfusion to osteoblasts outside the immediate fracture line is reduced, leading to ischemic death of those cells. Since the cortical bone depends on this intralamellar vascular network for survival of osteoblasts, their loss outside the break zone impairs healing and can contribute to necrosis in those regions. The other arterial systems—perforating periosteal (Volkmann’s) vessels supplying the periosteum, and the nutrient arteries feeding the medullary cavity—play roles in bone nutrition as well, but the described pattern of osteoblast death distant from the fracture most directly reflects ischemia from the Haversian (central) arterial network.

The blood supply inside cortical bone comes from the Haversian system, where central arteries run through the Haversian canals to nourish the osteoblasts and osteocytes in the surrounding lamellae. After a fracture, a clot forms and a vasospastic response can narrow these intramedullary cortical vessels. When the Haversian arteries go into spasm, perfusion to osteoblasts outside the immediate fracture line is reduced, leading to ischemic death of those cells. Since the cortical bone depends on this intralamellar vascular network for survival of osteoblasts, their loss outside the break zone impairs healing and can contribute to necrosis in those regions. The other arterial systems—perforating periosteal (Volkmann’s) vessels supplying the periosteum, and the nutrient arteries feeding the medullary cavity—play roles in bone nutrition as well, but the described pattern of osteoblast death distant from the fracture most directly reflects ischemia from the Haversian (central) arterial network.