Fig. 1

Focal cartilage thickening in the presence of an osteophyte and healthy metacarpal head cartilage. Legend. Ultrasound dorsal longitudinal scan of the hyaline cartilage of the 2nd metacarpal head moving the probe from the central force-bearing portion (A, D) to the proximal peripheral part of the metacarpal head (C, F) in a patient with hand osteoarthritis (A-C) and in a healthy control (D-F). Arrow: osteophyte, arrowheads: hyaline cartilage’s superficial margin, m: metacarpal head, p: proximal phalanx