Wolff's Law states that bone remodels in response to mechanical stress. The cellular mechanism mediating this mechanotransduction is best attributed to:

• A Osteoclasts detecting piezoelectric signals in compressed cortical bone
• B Osteocytes acting as mechanosensors, transmitting signals via lacunar-canalicular network to regulate osteoblast/osteoclast balance ✓
• C Periosteal fibroblasts releasing BMPs in response to tension
• D Woven bone produced by the marrow in response to cyclic loading

Explanation

Osteocytes (mature osteoblasts embedded in lacunae) are the primary mechanosensors of bone. Their long cytoplasmic processes form an interconnected lacunar-canalicular network that detects fluid shear stress from mechanical loading. Stimulated osteocytes modulate the RANK-RANKL-OPG axis and release sclerostin (an inhibitor of Wnt signalling) — unloaded osteocytes upregulate sclerostin, inhibiting bone formation, while loaded osteocytes suppress sclerostin, promoting osteoblastogenesis. This explains why immobilization causes disuse osteoporosis and loading stimulates bone formation. Piezoelectric signals in bone collagen and hydroxyapatite do occur but are sensed by osteocytes.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.