Dorsal transverse scan of the wrist
The patient sits, hand pronated, arm supported, with the probe placed transversely over the distal end of the radius. Lister’s tubercle on the distal radius is identified. Extensor pollicis longus lies on the ulnar side of the tubercle and extensor carpi radialis brevis on the radial side. Movement of the thumb identifies extensor pollicis longus.
The probe is moved to identify extensor carpi radialis brevis and extensor carpi radialis longus.
The probe is moved radially to identify the first compartment of the extensor tendons. This compartment contains the abductor pollicis and extensor pollicis brevis tendons. Movement of the thumb helps identify these tendons within the first compartment.
The probe now moves towards the ulnar side to identify the extensor digitorum and extensor indicis tendons in the fourth compartment. The fifth compartment contains the extensor digiti minimi tendon located above the radioulnar joint. Movement of the fingers identifies these tendons clearly.
The probe is now moved medially. Extensor carpi ulnaris is identified in the groove in the medial aspect of the ulna.