Contribution of lumbrical muscle activity to the paradoxical extension phenomenon induced by injuries to the finger flexor tendons

Toshio Kajiwara, Keiko Onogi, Hiroyuki Shimizu

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The "Extensor habitus" phenomenon occurs in finger flexor tendon injuries and consists of a paradoxical extension of the interphalangeal joints after an attempt to flex the finger. The mechanism of extension is considered to be a contraction of the flexor digitorum profundus that is then transmitted via the lumbrical muscle structure to the extensor expansion. Using electromyography, we recorded the lumbrical muscle activity during the paradoxical extension phenomenon to determine whether the lumbrical muscle contributed to this event. Two patterns of electromyographical activity of the lumbrical muscle were observed. Group I (6 fingers) displayed electrical activities in the lumbrical muscle during flexion tasks, while group II (12 fingers) did not. In group I, the lesions were mainly located in zone V, and the response to range of motion exercises was satisfactory. In group II, nearly all of the lesion were located in zone II, and half of the cases required additional surgical interventions. Group II appeared to exhibit the "Extensor habitus" phenomenon, while group I exhibited an "Extensor habitus-like phenomenon." To distinguish between these two phenomena, an electromyographical examination of the lumbrical muscle must be performed.

Original languageEnglish
Pages (from-to)175-178
Number of pages4
JournalKeio Journal of Medicine
Volume48
Issue number4
DOIs
Publication statusPublished - 1999

All Science Journal Classification (ASJC) codes

  • Medicine(all)

Fingerprint Dive into the research topics of 'Contribution of lumbrical muscle activity to the paradoxical extension phenomenon induced by injuries to the finger flexor tendons'. Together they form a unique fingerprint.

Cite this