Extensor Pollicis Longus

Posterior Interosseus Nerve, Radial Nerve, Posterior Cord, Posterior Division, Middle and Lower Trunk, C7, C8. 

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

The dorsal aspect of base of terminal phalanx of thumb. 

At mid-forearm insert needle electrode along radial border of ulnar. 

The electrode will travel through the extensor carpa ulnaris. 

---

Fig.l0.17a-f. Extensor tendons second and third compartments, a-c Transverse 15-7 MHz US images obtained distal to the Lister tubercle with d-f diagram correlation. From cranial (a) to caudal (c), US shows the extensor pollicis longus tendon as a thin fibrillar band (arrowheads) crossing the extensor carpi radialis brevis (ECRB) and longus (ECRL)... 

Fig. 10.33 a,b. Schematic drawings illustrate typical sites of overuse tendinopathies in the a dorsal and b ventral wrist, including Ay de Quervain tenosynovitis B, intersection syndrome C,extensor pollicis longus tenosynovitis, ),extensor carpi ulnaris tenosynovitis E, flexor carpi radialis tenosynovitis F, flexor digitorum superficialis and flexor digitorum profundus tenosynovitis Gy flexor carpi ulnaris tendinopathy... 

As already stated, the extensor pollicis longus tendon (third compartment of the extensor tendons) is a thin tendon that reflects over the medial aspert of the Lister tubercle before reaching the dorsum of the hand. Because of mechanical friction and its small size, the extensor poUicis longus is frequently affected by tenosynovitis that presents with local pain over the Lister tubercle and, less commonly, with local crepitus during thumb movements. This condition can be assodated with previous fractures of the distal radius... 

Denman 1979) and leads to considerable tendon weakness, partial and complete tears if untreated. In extensor pollicis longus tenosynovitis, the synovial sheath effusion is typically found just proximal to the Lister tuberde and after the tendon has crossed the extensor carpi radialis longus (Fig. 10.40). Due to the restricted space under the fasda, the synovial sheath of this tendon maybe distended with fluid in the area of the Lister tuberde and over the radial wrist extensors only wflien the amount of effusion is remarkable. 

De Flaviis L, Scaglione P,Nessi R et al (1988) Ultrasonography of the hand in rheumatoid arthritis. Acta Radiol 29 457-460 Denman EE (1979) Rupture of extensor pollicis longus a crush injury. Hand 11 295-298... 

If the needle electrode is inserted too radially it will be in the extensor pollicis longus and if inserted too proximally it will be in the... 

Dorsal surface of lower half of ulnar shaft below the origin of the extensor pollicis longus. 

---