Sono‐Anatomy and Histology of the Deep Fasciae in the Lower Limb

The deep fasciae of the lower limb represent a highly specialized network essential for efficient force transmission, segmental stability and coordinated mechanics of locomotion. Its collagen‐dense architecture forms a resilient and adaptive continuum that varies in thickness, fiber orientation and anchoring patterns from the thigh to the foot. Recently, the use of high‐resolution ultrasonography, supported by anatomical and histological evidence, revealed more intricate organization than traditionally illustrated. This is particularly true in the distal leg and ankle, where lattice‐like fiber arrangements, retinacular thickenings and deep anchoring bands form a dynamically integrated support system. These features confirm the functional continuity of fascial layers throughout the limb and their relevance in maintaining tendon alignment—modulating load transfer and stabilizing the ankle/foot complex. This paper provides a concise and systematic guide to the sono‐anatomy of lower‐limb deep fasciae. By integrating anatomical, histological and ultrasonographic perspectives, it highlights the clinical importance of fascia assessment.