Ultrasound guided steroid injection of the inter-phalangeal joints. a. The joint space (*) is seen as a gap between the proximal (P1) and distal (P2) phalanx. It should be clearly differentiated from the growth plates (G) of these bones. b. Simulated inter-phalangeal joint injection in a mannequin showing the advancement of the needle using an “out-of-plane” approach. c. The needle (arrow) is seen being advanced into this small joint space.