Figure 1

Ultrasound appearance of normal flexor tendon sheath and tenosynovitis. a, Normal appearance, longitudinal view. b, Normal appearance, transverse view. c, Flexor tenosynovitis, longitudinal view. d, Flexor tenosynovitis, transverse view. Arrows in c and d indicate tendon sheath thickening. MC: metacarpal; P: phalanx; FT: flexor tendon