Abbreviations: POST: Posterior; AX: Axial; LAT: Lateral; CEN: Central; MED: Medial The transducer positions used for axial posterior imaging acquisition of the elbow joint at the level L1 are shown. The positions of the transducer placed laterally (B), centrally (C) and medially (D) in relation to the central position of the joint are illustrated with accompanying sonographic images in a healthy volunteer. The distal humerus (*) has been marked. The transducer position used for axial posterior imaging acquisition of the elbow joint at the level L3 is shown. The positions of the transducer placed laterally (E) in relation to the central position of the joint is illustrated with accompanying sonographic images in a healthy volunteer. The radial head (***) has been marked.

Figure 5: The locations delineated with gel in supine position represent the positions of the transducer for acquisition of axial posterior ultrasound images. The levels shown are L1, AX, POST, LAT; L1, AX, POST, CEN; L1, AX, POST, MED; L3, AX, POST, LAT.