Ann Rehabil Med.  2013 Feb;37(1):151-155. 10.5535/arm.2013.37.1.151.

Anomalous Course of the Extensor Pollicis Longus With Multiple Absences of Thumb Muscles

• Hong J
• Kim DK
• Kang SH
• Seo KM

• KMID: 2266666
• DOI: http://doi.org/10.5535/arm.2013.37.1.151

Abstract

We report a rare case of a 10-year-old girl with anomalous course of extensor pollicis longus (EPL) muscle, which exists with absence of thenar muscles and muscles in the 1st extensor compartment. Her chief complaint was severe atrophy on the right thenar eminence. On physical examination, there was no obvious functional abnormality on her right thumb. On magnetic resonance imaging, we found that the abductor pollicis brevis, opponens pollicis, abductor pollicis longus, and extensor pollicis brevis muscles were absent. The tendon of the EPL muscle was found, but it had abnormal insertion on the radial side of the proximal phalanx, not on the distal phalanx. This variation was thought to have played a major role in compensating for impaired abduction of the thumb, which is usually accompanied by agenesis of major abductors of the thumb.

Keyword

Congenital abnormalities; Thumb; Anomalous insertion

MeSH Terms

Atrophy
Congenital Abnormalities
Magnetic Resonance Imaging
Muscles
Physical Examination
Tendons
Thumb

Figure

• 

  Fig. 1 (A) Thenar eminence of the right hand showed severe atrophy compared with that of the left hand. (B) Interphalangeal joint of the right thumb was not fully extended.

• 

  Fig. 2 Proton density-weighted axial image of right wrist magnetic resonance imaging. (A) At trapeziometacarpal joint level, the flexor pollicis longus tendon (*), flexor pollicis brevis muscle (**), adductor pollicis muscle (◊), and radial artery (arrow) were observed normally, but abductor pollicis brevis, opponens pollicis (white ellipse is a location where abductor pollicis brevis, opponens pollicis were observed in normal subject) were not. (B) At wrist joint level, the 1st extensor compartment (black ellipse) is empty.

• 

  Fig. 3 Proton density-weighted coronal image of right wrist magnetic resonance imaging. (A) At the metacarpal bone level, the extensor pollicis longus tendon was running in the 1st compartment area (arrow). (B) The extensor pollicis longus was inserted onto the proximal phalanx base of thumb (arrow).

Reference

1. Shiraishi N, Matsumura G. Anatomical variations of the extensor pollicis brevis tendon and abductor pollicis longus tendon: relation to tenosynovectomy. Okajimas Folia Anat Jpn. 2005; 82:25–29. PMID: 15934601.

2. Fernandez D, Gupta S, Fallon P. Congenital thenar hypoplasia with absent radial artery: a case report. Eur J Paediatr Neurol. 2009; 13:277–279. PMID: 18571945.

3. Su CT, Hoopes JE, Daniel R. Congenital absence of the thenar muscles innervated by the median nerve: report of a case. J Bone Joint Surg Am. 1972; 54:1087–1090. PMID: 5057104.

4. Jackson WT, Viegas SF, Coon TM, Stimpson KD, Frogameni AD, Simpson JM. Anatomical variations in the first extensor compartment of the wrist: a clinical and anatomical study. J Bone Joint Surg Am. 1986; 68:923–926. PMID: 3733780.

5. Yoshida Y. Anatomical study on the extensor digitorum profundus muscle in the Japanese. Okajimas Folia Anat Jpn. 1990; 66:339–353. PMID: 2336244.

6. Rubin G, Wolovelsky A, Rinott M, Rozen N. Anomalous course of the extensor pollicis longus: clinical relevance. Ann Plast Surg. 2011; 67:489–492. PMID: 21407056.

7. Gupta S, Michelsen-Jost H. Anatomy and function of the thenar muscles. Hand Clin. 2012; 28:1–7. PMID: 22117918.

8. Ogino T, Ishii S. Opponensplasty by abductor digiti minimi for hypoplastic thumb. Orthop Traumatol. 1995; 4:29–36.

9. Neviaser RJ. Congenital hypoplasia of the thumb with absence of the extrinsic extensors, abductor pollicis longus, and thenar muscles. J Hand Surg Am. 1979; 4:301–303. PMID: 469205.

10. Tay SC, Moran SL, Shin AY, Cooney WP 3rd. The hypoplastic thumb. J Am Acad Orthop Surg. 2006; 14:354–366. PMID: 16757675.