Abductor Pollicis Longus

Type B and C fractures are Salter-Harris II injuries. Type B injuries are the more common, and have the metaphyseal spur on the medial side, and apex lateral angulation due to the pull of abductor pollicis longus (Fig. 19.29). Type C fractures have the opposite pattern, i.e. the spur is lateral and the angulation is apex medial (Figs. 19.30,19.31). Angulated Type C fractures are more difficult to treat by closed reduction than type B, but both are problematic. 

Fig. 10.11 a—c. Extensor tendons first compartment, a Short-axis 15-7 MHz US image obtained over the first compartment of the extensor tendons with b diagram correlation demonstrates the abductor poUicis longus (APL) and extensor pollicis brevis (EPB) tendons which appear closely apposed and retained over the radial styloid by the retinaculum (arrowheads). The radial artery (RA) is seen on the lateral aspect of the abductor pollicis longus. c Probe positioning and field-of-view of the US image relative to the dorsal wrist structures... 

Fig. 10.14a-d. Radial nerve, a Photograph of the lateral aspect of the wrist showing the relationship of the superficial cutaneous branch of the radial nerve (white dashed line) with the extensor tendons of the first (I) and third (111) compartment, b-d Transverse 15-7 MHzUS images over the first compartment of the extensor tendons obtained at the levels (horizontal black bars) indicated in a show the radial nerve (arrow) as it crosses the abductor pollicis longus (APL) and extensor pollicis brevis tendons (EPB) to reach the dorsal aspect of the hand. At the wrist, the radial nerve is very small and can be depicted as a tiny hypoechoic image only when very high-frequency transducers are used... 

Fig. 10.38 a-c. Wartenberg syndrome. a,b Short-axis and c long-axis 15-7 MHz US images over the radial nerve at the wrist in a patient with symptoms of superficial radial neuropathy after intravenous infusion in the cephalic vein, a Proximal to the level of injury, a normal-appearing nerve (arrow) is seen adjacent to an occluded cephalic vein (arrowhead). b,c At the level of puncture, a fusiform hypoechoic thickening of the nerve (arrow) with loss of the fascicular echotexture can be appreciated as a result of trauma. Note the position of the nerve relative to the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons... 

The flexor pollicis longus tendon traverses the thenar eminence between the superficial and deep bellies of the flexor pollicis brevis muscle. It then enters the osteofibrous canal of the thumb to insert at the volar aspect of the base of the distal phalanx. At the metacarpal head level, this tendon courses between two sesamoid bones, one (lateral) included in the combined tendon of the flexor pollicis brevis and abductor pollicis longus, the other (medial) in the adductor pollicis tendon. 

Dorsal surface of radial shaft below abductor pollicis longus and in the interosseus membrane. 

The dorsal surface of the middle third of ulnar shaft below the abductor pollicis longus. 

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